Note: Descriptions are shown in the official language in which they were submitted.
--1--
EMULSIONS AND PHOTOGRAPHIC ELEMENTS CONTAINING SILVER
~ALIDE GRAINS HAVI~G ICOSITETRAHEDRAL CRYSTAL FACES
Field of the Invention
This invention relates to photography. More
specifically, this invention is directed to
photographic emulsions containing silver halide grains
and to photographic elements containing these
emulsions.
Brief Description ~ the Drawing~
Figure 1 is an isometric view of a regular
cubic silver halide grain;
Figure 2 is a æchematic diagram of the atomic
arrangement at a silver bromide cubic crystal surface;
Figure 3 is an isometric view of a regular
octahedral silver halide grain;
Figure 4 is a schematic diagram of the atomic
arrangement at a silver bromide octahedral crystal
surface;
Figure 5 is an isometric view of a re~ular
rhombic dodecahedron;
Figure 6 is a schematic diagram of the atomic
arrangement at a silver bromide rhombic dodecahedral
crystal surface;
Figure 7 is an isometric view of a regular
cubic silver halide grain, a regular octahedral silver
halide grain, and intermediate cubo-octahedral silver
halide grains.
Figures 8 and 9 are front and rear isometric
views of a regular {211} icositetrahedron;
Figures 10 and 11 are schematic diagrams of
theorized atomic arrangements at silver bromide
icositetrahedral crystal surfaces of Miller indices of
{211} and {533}, respectively;
Figures 12 through 27 and 31B are electron
35 micrographs of icositetrahedral silver halide grains;
Figures 28, 29B, 29C, 30C, 30D, and 31A are
electron micrographæ of silver halide grains having
8~ 7
--2--
icositetrahedral protrusions on host grains;
Figures 29A, 30A, and 30B are electron
mlcrographs of tabular grain emul6ions without
icositetrahedral protrusions;
Figures 32A and 32B are plots of image
density versus wavelength of exposure; and
Figures 29A, 30A, and 30B are electron
micrographs of tabular grain emulsions without
icoæitetrahedral protrusions.
Ba~ground of ~h~ Invention
Silver halide photography has been practiced
for more than a century. The radiation sensitive
silver halide compositions initially employed for
imaging were termed emulsions, since it was not
originally appreciated that a solid phase was
present. The term "photographic emulsion" has
remained in use, although it has long been known that
the radiation sensitive component is present in the
form of dispersed microcrystals, typically referred to
as grains.
Over the years silver halide grains have been
the eubject of intense investigation. Although high
iodide silver halide grains, those containing at least
90 mole percent iodide, based on silver, are known and
have been suggested for photographic applications, in
practice photographic emulsions almost always contain
silver halide grains comprised of bromide, chloride,
or mixtures of chloride and bromide optionally
containing minor amounts of iodide. Up to about 40
mole percent iodide, based on silver, can be
accommodated in a silver bromide crystal structure
without observation of a separate silver iodide
phase. However, in practice silver halide emulsions
rarely contain more than about 15 mole percent iodide,
with iodide well below 10 mole percent being most
common.
1~81'~'~7
--3--
All silver halide grains, except high iodide
silver halide grains, exhibit cubic crystal lattice
~tructures. However, grains of cubic crystal lattice
structures can differ markedly in ~ppearance.
In one form silver halide grains when
microscopically observed are cubic in appearance. A
cubic grain 1 is shown in Figure 1. The cubic grain
is bounded by six identical crystal faces. In the
photographic literature these crystal faces are
10 usually referred to as {100} crystal faces,
referring to the Miller index employed for designating
crystal faces. While the ~100} crystal face
designation is most commonly employed in connection
with silver halide grains, these same crystal faces
are sometimes also referred to as {200} crystal
faces, the difference in designation resulting from a
difference in the definition of the basic unit of the
crystal structure. Although the cubic crystal shape
is readily visually identified in regular grains, in
irregular grains cubic crystal faces are not always
square. In grains of more complex shapes the presence
of cubic crystal faces can be verified by a
combination of vi6ual inspection and the 90 angle of
intersection formed by adjacent cubic crystal faces.
The practical importance of the {lO0}
crystal faces i8 that they present a unique surface
arrangement of silver and halide ions, which in turn
influences the grain surface reactions and adsorptions
typically encountered in photographic applications.
This unique surface arrangement of ions as theore-
tically hypothesized is schematically illustrated by
Figure 2, wherein the smaller spheres 2 represent
silver ions while the larger spheres 3 designate
bromine ions. Although on an enlarged scale, the
relative size and position of the silver and bromide
ions is accurately represented. When chloride ions
1~31Z;~7
-4-
are substituted for bromide ions, the relative
arrangement would remain the same, although the
chloride ions are smaller than the bromide ionæ. It
can be seen that a plurality of parallel rows,
indicated by lineæ 4, are present, each formed by
alternating silver and bromine ions. In Figure 2 a
portion of the next tier of ions lying below the
æurface tier is shown to illuætrate their relationship
to the surface tier of ions.
In another form silver halide grains when
microscopically observed are octahedral in appear-
ance. An octahedral grain 5 is shown in Figure 3.
The octahedral grain is bounded by eight identical
crystal faceæ. These crystal faces are referred to as
~111} crystal faces. Although the octahedral
crystal shape is readily visually identified in
regular grains, in irregular grains octahedral crystal
faces are not always triangular. In grains of more
complex shapes the presence of octahedral crystal
faces can be verified by a combination of visual
inspection and the 109.5 angle of intersection formed
by adjacent octahedral crystal faces.
Ignoring possible ion adsorptions, octahedral
crystal faces differ from cubic crystal faces in that
the surface tier of ions can be theoretically
hypothesized to consist entirely of silver ions or
halide ions. Figure 4 i8 a schematic illustration of
a {111} crystal face, analogous to Figure 2,
wherein the smaller sp~ere~ 2 represent ~ilver ions
while the larger spheres 3 designate bromine ions.
Although silver ions are shown at the surface in every
available lattice position, it has been suggested that
having silver ions in only every other available
lattice position in the surface tier of atoms would be
more compatible with surface charge neutrality.
Instead of a surface tier of silver ions, the surface
. . ..
~ ~ 81~7
tier of ions could alternatively be bromide ions. The
tier of ions immediately below the surface silver ions
consists of bromide ions.
In comparing Figures 1 and 2 with Figures 3
and 4 it is important to bear in mind that both the
cubic and octahedral grains ha~e e~actly the same
cubic crystal lattice ~tructure and thus exactly the
same internal relationship of silver and halide ions.
The two grains differ only in their surface crystal
faces. Note that in the cubic cry~tal face of Figure
2 each surface silver ion lies immediately adjacent
five halide ions, whereas in Figure 4 the silver ions
at the octahedral crystal faces each lie immediately
adjacent only three halide ions.
Much less common than either cubic or
octrahedral silver halide grains are rhombic
dodecahedral silver halide grains. A rhombic
dodecahedral grain 7 is shown in Figure 5. The
rhombic dodecahedral grain is bounded by twelve
identical crystal faces. These crystal faces are
referred to as {110} (or, less commonly in
reference to silver halide grains, {220}) crystal
faces. Although the rhombic dodecahedral crystal
shape is readily vieually identified in regular
grains, in irregular grains rhombic dodecahedral
crystal faces can vary in shape. In grains of more
complex shapes the presence of rhombic dodecahedral
crystal faces can be verified by a combination of
visual inspection and measurement of the angle of
intersection formed by adjacent crystal faces.
Rhombic dodecahedral crystal faces can be
theoretically hypothesized to consist of alternate
rows of silver ions and halide ions. Figure 6 is a
schematic illustration analogous to Figures 2 and 4,
wherein it can be seen that the surface tier of ions
is formed by repeating pairs of silver and bromide ion
A
lX~ 7
-6-
parallel rows, indicated by lines 8a and 8b,
respectively. In Figure S a portion of the ne~t tier
of ions lying below the surface tier is æhown to
illustrate their relationship to the surface tier of
ions. Note that each surface silver ion lies
immediately adjacent four halide ions.
Although photographic silver halide emulsions
containing cubic crystal lattice structure grains are
known which contain only regular cubic grains, such as
the grain shown in Figure 1, regular octahedral
grains, such as the grain shown in Figure 3, or, in
rare instances, regular rhombic dodecahedral grains,
such as the grain shown in Figure 5, in practice many
other varied grain shapes are also observed. For
example, silver halide grains can be cubo-octa-
hedral -that is, formed of a combination of cubic and
octahedral crystal faces. This is illustrated in
Figure 7, wherein cubo-octahedral grains 9 and 10 are
shown along with cubic grain 1 and octahedral grain
5. The cubo-octahedral grains have fourteen crystal
faces, six cubic crystal faces and eight octahedral
crystal faces. Analogous combinations of cubic and/or
octahedral crystal faces and rhombic dodecahedral
crystal faces are possible, though rarely encoun-
tered. Other grain shapes, such as tabular grains androds, can be attributed to internal crystal
irregularities, such as twin planes and ~crew
dislocations. In most instances some corner or edge
rounding due to solvent action is observed, and in
some instances rounding is so pronounced that the
grains are described as spherical.
It is known that for cubic crystal lattice
structures crystal faces can take any one of seven
possible distinct crystallographic forms. However,
for cubic crystal lattice structure silver halides
only grains having {100} (cubic), {lll}
~`~
~'~
--7--
(octahedral), or, rarely, {110} (rhombic
dodecahedral) crystal faces, individually or in
combination, have been identified.
It is thus apparent that the photographic art
ha3 been limited in the crystal faces pre~ented by
silver halide grains of cubic crystal lattice
structure. As a result the art has been limited in
modifying photographic properties to the choice of
surface sensitizers and adsorbed addenda that are
10 workable with available crystal faces, in most
instances cubic and octahedral crystal faces. This
has placed restrictions on the combinations of
materials that can be employed for optimum photo-
graphic performance or dictated accepting less than
optimum performance.
F. C. Phillips, An Int~oduction tQ
CrystallQgraphy, 4th Ed., John Wiley ~ Sons, 1971, is
relied upon as authority for the basic precepts and
terminology of crystallography herein presented.
James, The Theory of the Photographic
Pr~cess, 4th Ed., Macmillan, New York, 1977, pp. 98
through 100, is corroborative of the background of the
invention described above. In addition, James at page
98 in reference to silver halide grains states that
high Miller index faces are not found.
Berry, "Surface Structure and Reactivity of
AgBr Dodecahedra", ~LQ~ogra~hic Scie~ce a~
~gineering, Vol. 19, No. 3, May/June 1975, pp. 171
and 172, illustrates silver bromide emulsions
containing {110} crystal faces.
Klein et al, "Formation of Twins of AgBr and
AgCl Crystals in Photographic Emulsions", Photogr -
phische Korrespondenz, Vol. 99, No. 7, pp. 99-102
(1963) describes a variety of singly and doubly
twinned silver halide crystals having {100}
,.
~L~8~ 7
--8--
(cubic) and {lll} (octahedral) crystal faces.
Klein et al is of interest in illustrating the variety
of shapes which twinned æilver halide grains can
assume while still exhibiting only {111} or
{100} crystal faces.
A. P. ~. Trivelli and S. E. Sheppard, The
Silver Bromide Grain of Photo~raphic Emul~ions, Van
Nostrand, Chapters VI and VIII, 1921, is cited for
historical interest. Magnifications of 2500X and
lower temper the value of these observations. Much
higher resolutions of grain features are obtainable
with modern electron microscopy.
W. Reinders, ~Studies of Photohalide
Crystals~, Kolloid-Zeitschrift, Vol. 9, pp. 10-14
(1911); W. Reinders, ~Study of Photohalides III
Absorption of Dyes, Proteins and Other Organic
Compounds in Crystalline Silver Chloride", Zeit~chrift
~ hy~ Li~hQ ~h~i~. Vol. 77, pp. 677-699 (1911~;
Hirata et al, "Crystal Habit of Photographic Emulsion
20 Grains~, 1 Photog. ~Q~. of Japan, Vol. 36, pp.
359-363 (1973); Locker U.S. Patent 4,183,756; and
Locker et al U.S. Patent 4,225,666 illustrate
teachings of modifying silver halide grain shapes
through the presence of various materials present
during silver halide grain formation.
~ummary of ~ Inven~LQ~
In one aspect this invention is directed to a
silver halide photographic emulsion comprised of
radiation sensitive silver halide grains of a cubic
crystal lattice structure comprised of icositetra-
hedral crystal faces.
In another aspect this invention is directed
to a photographic element containing at least one
emulsion of the type previously described.
The invention presents to the art for the
first time the opportunity to realize the unique
1~:8~X7
_g_
surface configuration of icositetrahedral crystalfaces in photographic silver halide emulsions. The
invention thereby renders accessible for the first
time a new choice of crystal faces for modifying
photographic characteristics and improving interac-
tions with sensitizers and adsorbed photographic
addenda.
Descri~tion of Preferred Embodiments
The present invention relates to silver
halide photographic emulsions comprised of radiation
sensitive silver halide grains of a cubic crystal
lattice structure comprised of icositetrahedral
crystal faces and to photographic elements containing
these emulsions.
In one form the silver halide grains can take
the form of regular icositetrahedra. A regular
icositetrahedron 11 ls shown in Figures 8 and 9, which
are front and back views of the same regular
icositetrahedron. An icositetrahedron has twenty-four
identical faces. Al~hou~h any grouping of faces is
entirely arbitrary, the icositetrahedron can be
visualized as six separate clusters of crystal faces,
each cluster containing four separate faces. In
Figure 8 faces 12a, 12b, 12c, and 12d can be
visualized as members of a first cluster of faces. In
Figure 9 faces 13a, 13b, 13c, and 13d can be
visualized as members of a second cluster of faces.
The remaining four clusters of faces each have two
faces visible in Figure 8 and two faces visible in
Figure 9. Faces 14a and 14b, shown in Figure 8, and
faces 14c and 14d, shown in Figure 9, represent the
four faces of a third cluster of four faces.
Similarly, faces 15a and 15b, shown in Figure 8, and
faces 15c and 15d, shown in Figure 9, represent the
four faces of a fourth cluster of four faces. Faces
16a and 16b, shown in Fi~ure 8, and faces 16c and
1;~81'~7
-10-
15d, shown :Ln Flgure 9, represent the four faces of a
fifth cluster of four faces while 16a, 16b, and 16c,
shown ln Flgure 8, snd face 16d, shown in Figure 9,
complete a ~i.fth cluster of fsce.~ while face.n 17a and
17b, ~ho~n Ln Fi~ure 8, and fsces 17c and 17d, ~hown
Ln Figure 9, repre~ent the four faces of a sixth
cl.uster of four faces.
Looking at the icositetrahedron it can be
seen th~t there Are four intersections of ad~ecent
faces wLthin each cluster, and there are two face
lntersections of eac}l cluster with each of the four
clus~ers ad~¢ to lt for a tot~l of forty-eight
face edge .LntersRction3. The relative angles formed
by lnte~sect.Lng fRces have only two different
values. Al.l i.ntersections of a face from one cluster
wlth a face from another cluster sre identical,
torming a fJ.rst relatlve angle. Looking at Figure 8,
the relative anKle o adjecent fsces 12a and 14a, 12a
and 15a, 12b and 15d, 12b and 17a, 12c and 16b, 12c
and 17b, 12d snd 16a, and 12d and 14b are all at the
Ldent1cal fi.rst relative angl.e. All adJacent face~
within each cluster intersect at the same relative
angle, whi.ch is di~ferent from the relative angle of
Lntersection of faces in d~fferent clusters. Looking
at one cl.uster i.n wh1.ch all faces are fully vl~ible,
the .intersecti.ons between faces 12a and 12b, 12b and
12c, 12c and 12d, and 12d and 12a sre all at the same
relative angle, referred to as a second relative
angle. Whlle the regular icositetrahedron has a
distLnct.Lve appearance thst can be recogni~ed by
visual lnspecti.on, tt shoul.d be appreciated that
measurement of any one of the two relative angles
provldeg A corroboratl.on o~ ad~acent hexoctahedral
crystal faces.
In crystallography measurement of relative
angles ol` adJacent crystal. faces is employed for
posLtLve crystal face identification. Such tech-
~ 8~ 7
nlques are de~crt.bed, for ex~mple, by Phillips, cited
ahove. These technlques can be combined with
technlques for the mlcroscoplc examination of silver
halide grains to identLfy positively the icositetra-
hedral crystQI. faces of ~ilver halide grain~.Technlques for preparing electron micrographs of
~il.ver halide grai.ns are ~enerally well known in the
art, as lllustrated by B.M. Spinell and C.F. O~ter,
"Photographic Materlals", The EncYcloPedia of
MicroscoPv and M~crotechnique, P. Gray, ed., Van
No~trand, N.Y., 1973, pp.427-434, note particularly
the section dealing with carbon replica electron
mlcro~copy on papJes 429 and 430. Employing tech-
niques well known J.n el.ectron microscopy, carbon
replicas of sllver halide p,rains are flrst prepared~
The carbon replicas reproduce the grain shRpe while
avo.idi.ng shape alterlng sl.lver print-out th~t is
known to result from empl.oytng the silver halide
eralns wlthout carbon shel.ls. An electron scanning
beam rather than llght is employed for imaging to
permit hlgher ran~es of magnification to be realized
than when l:leht ls employed. When the grains sre
sufflciently spread apart thst adjacent grains are
not lmpi.ngtng, the grai.n~ lie flat on one crystal
face rather than on a co1.~n (i.e., a polnt)~ By
tLlting the sample being viewed relative to the
electron beam a selected grain can be oriented so
th~t the l.ine of slght is sub~tantially parallel to
both the line of lntersection of two ad~acent crystal
faces, seen ~9 a point, and each of the two inter-
sectlng crystal faces, seen as edges. When the grain
faces are parallel to the i.msging electron beam, the
two Go~re~pondine e~ges of the gr~in which they
def:lne wlll appeer sharper than when the faces are
merely close to belng parallel. Once the deqired
graln orlentati.on wlth two intersectlng crystal faces
present:lng a parallel edge to the electron be~m is
8~ 7
-12-
obt~ined, the angle of intersection can be measured
from an electron micro~raph of the oriented grain.
In thls way adJacent lcosl.tetralledral crystal f~ce
can be ldentlfi.ed. Relative ~ngles of icositetr~he-
S dral and adJacent cryqt~ ces of other Millerindice~ can ~190 be determined in the ssme w~y.
Again, the unique relative angle allow3 a positive
ldenttflcati.on of the cryAtal faceq. While relative
angle measurements can ~e definitive, in many, if not
most, ~nstances vLAual. lnspection of grains by
electron microscopy a110ws immediate identification
of Lco~itetrshedr~l crystal face~.
ReferrLng to the mutu~lly perpendiculsr x,
y, Hnd z axes of a cubLc crystal lattice, it is well
recognized ln the art that cubic crystal faces are
parallel to two of the axes and intersect the third,
thus tSle {100~ MLller lndex ssslgnment; octshe-
dral crystal. faces intersect each of the three axes
at an equal interv~l, thu~ the {111} Miller index
~ss~nment; and rhom~:i.c dodecahedral crystal faces
I.ntersect two of the three sxes at sn equal interv~l
and sre parallel to the third axis, thus the
{110~ Mlller index ~slgnment. For a given
deflnit{on of the baslc cryatal unit, there i8 one
and only one Mlller lndex asslgnment for each of
cublc, octahedral, and rhomhLc dodecshedral crystal
f~ces.
IcosLtetrahedral crystal faces include a
family of crystal f~ces that can have differing
Miller index values. Ico~itetrahedral cryst~l faces
~re generical.ly des.lgnated as {hQQ} crystal
faces, wherein h and Q sre different integers each
greater th~n zero and h ls 8re~ter than ~. The
regular i.co~Ltetrahedron 11 shown in Figures 8 ~nd 9
consist~ of ~ crystal faces, which corre-
sponds to the lowe~t value th~t h and Q can each
represent. A regulQr icosLtetrshedron having
Z~
-13-
{311}, {322}, {411}, {433},
~511}, {5~}, {533}, or {544} crystal
faces would sppe~r simil~r to the lcositetrshedron ,
ll, but the h:l.gher Mlller indices would result in
changes ln the ~ngles of intersection. Although
there i9 no theoret.lc~l li.mit on the msximum values
of the integers h snd Q, lcositetrshedrsl crystal
~sces havlng 8 v~lue of h of 5 or lesq are more
essily genersted. For this ree30n, silver halide
grsins hsvlng icos.ttetrahedral crystal fsces of the
exemplary Mlller index vslue~ identified sbove sre
preferred. Wlth practice one icositetrshedr~l
crystal face csn often be distinguished visually from
snother of a d:lfferent Mll.ler index value. Measure-
ment of relstive sngles permits positive corrobors-
tJ.on of the specific Mi.ller index value icositetrahe-
dral cryst~l fsces present.
In one form the emulsions of this invention
contain sllver hsllde grsins which sre bounded
entLrely by icositetrshedrsJ. crystsl fsces, thereby
formlng bssicslly ~ep,ulsr lcositetrahedra. In
pract).ce slthoueh some edge roundinp, of the grsins is
ususlly pre~ent., the unrounded residual flst
icosltetrahedral. f.aces permlt pos~tive identifica-
tlon, since a sharp intersecting ed8e i9 unnecessary
to estsbllshlng the relative angle of ad~scent
lcosltetr~hedral. cryst~l. faces. Sighting to orient
the gralns is still possible employing the residual
flat crystal face portlonq.
The radtation sensitive silver halide grains
present ln the emulslons of this invention sre not
confined to those ~n whlch the icositetr~hedrsl
cryst~l fsce~ sre the only flst crystsl faceq
present. Juqt ss cubo-octahedrsl silver halide
grslns, such ss 9 and 10, exhibit both cubic snd
octahedr~l crystal fsces and 8erry, cited sbove,
reports grslns hRvJ.ng cublc, octshedrsl, ~nd rhombic
~28~X'~
--14
dodecahedrsl crystal faces in a single grain, the
rsdiation sensitive grains herein contemplated can be
formed by icositetrahedrAl crystal faceQ in comb1na-
tion with any one or combination of the other types
of crystal faces po~sible with a silver halide cubic
crystal lattice structure. For example, if conven-
tional silver halide grains having cubic, octahedral,
and/or rhombic dodecahedral crystal faces are
employed as host grains for the preparation of silver
halide grains having icositetrahedral crystal faces,
stopping silver halide deposition onto the host
grains before the original crystal faces have been
entirely overgrown by silver halide under conditions
favoring icositetrahedral crystal face formation
results in both icositetrahedral crystal faces and
residual crystal faces corresponding to those of the
original host grain being present.
In another variant form deposition of silver
halide onto host &rains under conditions which favor
icositetrahedral crystal faces can initially result
in ruffling of the grain surfaces. Under close
examination it has been observed that the ruffles are
provided by protrusions from the host grain ~urface.
Protrusions in the form of ridges have been observed,
but protrusions, when present, are more typically in
the form of pyramids. Pyramids pre~enting ico~ite-
trahedral crystal f~ces on host grains initially
presenting {lO0} crystal faces have four surface
faces~ These correspond to the four faces of any one
of the 12, 13, 14, 15, 16, or 17 series clusters
described above in connection with the icositetrahe-
dron 11. When the host grains initially present
~111) crystal faces, pyramids bounded by three
surface faces are formed. Turning to F~gure 8, the
apex of the pyramid correspond~2 to the coign formed
faces 12b, 15d, and 17a. The protrusions, whether in
~81~;~7
5--
the form of ridges or pyramids, can with~n a short
time of initiating precipitation onto the host grains
substan~ially cover the original host grain surface.
If silver halide deposition is continued after the
S entire grain surface 1~ bounded by icositetrahedral
crystal faces, the protrusions become progressively
larger snd eventually the grains lose their ruffled
appearsnce as they present larger and larger
icositetrahedral crystal faces. It is possible to
grow a regular icositetrahedron from a ruffled grain
by continuing silver halide deposition.
Even when the grains are not ruffled and
bounded entirely by icositetrahedral crystal faces,
the grains can take overall shapes differing from
regular icositetrahedrons. This can result, for
example, from irregularities, such as twin planes,
present in the host grains prior to growth of the
icositetrahedral crystal faces or introduced during
growth of the icositetrahedral crystal faces.
The important feature to note is that if any
crystal face of a silver halide grain is an icosi-
tetrahedral crystal face, the resulting grain
presents a unique arrangement of surface silver and
halide ions that differs from that presented by all
other possible crystal faces for cubic crystal
lattice structure silver halides. ThiQ unique
surface arrangement of ions as theoretically
hypothesized is schematically illustrated by Figure
10, wherein a {211) lcositetrahedral crystal face
is shown formed by silver ions 2 and bromide ions 3.
Comparing Figure 10 with Figures 2, 4~ and 6, it is
apparent that the surface positioning of silver and
bromide ions in each figure is distinctive. The
{211} icositetrahedral crystal face presents an
ordered, but more varied arrangement of surface
silver and bromide ions than is presented at the
~ 2~7
-16-
cubic, octahedral, or rhombic dodecahedral silver
bromide crystal faces. This is the result of the
tiering that occurs at the {211} icositetrahedral
crystal fsce. Icositetrahedral crystal faces with
differing Miller indices also exhlbit tiering. The
differing Miller indices result in analogous, but
nevertheless unique urface arrangements of silver
snd halide ions. The difference between icositetra-
hedral crystal faces of differing Miller indices is
illustrated by comparing Figure 10, which is a
hypothetical schematic diagram of a {211} crystal
face, and Figure 11, which is a corresponding diagram
of a {533} crystal face.
While Figures 2, 4, 6, 10, and 11 all
contain bromide ions as the sole halide ions, it is
appreciated that the same observations as to
differences in the crystal faces obtain when each
wholly or partially contains chloride ions instead.
Although chloride ions are substantially smaller in
effective diameter than bromide ions, an icositetra-
hedral crystal surface presented by silver chloride
ions would be similar to the corresponding sllver and
bromide ion surfaces.
The cubic crystal lattice structure silver
halide grains containing icositetrahedral crystal
faces can contain minor amounts of iodide ions,
similarly ~IS conventional silver halide grai~s.
Iodide ions have an effective diameter substantially
larger than that of bromide ions. As is well known
in silver h~lide crystallography, this has a somewhat
disruptive effect on the order of the crystal
structure, which can be accommodated and actually
employed photographically to advantage, provided the
iodide ions are limited in concentration. Preferably
iodide ion concentrstion~ below 15 mole percent and
optimally below lO mole percent, based on silver, are
1;~8~7
-17-
employed in the practice of this invention. Iodide
ion concentrations of up to 40 mole percent, based on
silver, can be present in silver bromide cry~tals.
Since iodide ions as the sole halide ion~ in silver
halide do not form a cubic crystal lattice structure,
their use slone hss no applicability to this
invention.
It is appreciated that the larger the
proportion of the total silver halide grain surface
area accounted for by icositetrahedral crystal faces
the more distinctive the silver halide grains
become. In most instances the icositetrahedral
crystal faces account for at least 50 percent of the
total surface area of the silver halide grains.
Where the grains are regular, the icositetrahedral
crystal faces can account for all of the flat crystal
faces observable, the only remaining grain surfaces
being attributable to edge rounding. In other words t
silver halide grains having icositetrahedral crystal
faces accounting for at least 90 percent of the total
grain sur~ace area are contemplated.
It is, however, appreciated that distinctive
photogr~phic effects may be realized even when the
icositetrahedral crystfll faces are limited in areal
extent. For example, where in an emulsion cont~lnlng
the silver hal~de grains a photographic addendum is
present thut shows a marked adsorption preference for
an icositetrahedral crystal face, only a limited
percentage of the total grain surface may be required
to produce a distinctive photographic effect.
Generally, if any icositetrahedral crystal f~ce is
observable on a silver halide grain, it accounts for
a sufficient proportion of the total surface area of
the silver halide grain to be capable of influencing
photographic performance. Stated another way, by the
time an icositetrahedral crystal face becomes large
8 ~ ~7
-18-
enough to be identified by its relative angle to
ad~acent crystal faces, it is already large enough to
be capable of influencing photographic perfor~ance.
Thus, the min~mum proportion of total grain surface
S area accounted for by icositetrahedrAl crystal faces
is limited only by the observer's ability to detect
the presence of icositetrahedral crystal faces.
The successful formation of icositetrahedral
crystal faces on silver halide grains of a cubic
crystal lattice structure depends on identifying
silver halide grain growth conditions that retard the
surface growth rate on icositetrahedral crystal
planes. It is generslly recognized in silver halide
crystallography that the predominant crystal faces of
a silver halide grain are determined by choosing
grain growth conditions that are least f&vorable for
the growth of that crystal face. For example,
regular cubic silver halide grains, such as grain 1,
are produced under grain growth conditions that favor
more rapid deposition of silver and halide ions on
all other available crystal faces than on the cubic
cry~tal faces. Referring to Figure 7, if an
octahedral grain, such as regulsr octahedral grain 5
i8 sub~ected to growth under conditions that least
favor deposltion of silver and halide ions onto cubic
crystal faces, grain 5 during continued silver halide
precipitation will progress through the intermediate
cubo-octahedral grain forms 9 and 10 before reaching
the final cubic grain configuration 1. Once only
cubic crystal faces remain, then ~ilver and halide
ions deposit isotropically on these surfaces. In
other words, the grain shape remains cubic, and the
cubic grains merely grow larger as additional silver
and halide ions sre precipitated.
By analogy, grains having icositetrahedrsl
crystal faces have been prepared by introducing into
-19-
a silver halide precipit~tion reaction vessel host
grains of conventional crystal faces, such as cubic
gr~ins, while maintaining growth conditions to favor
retarding silver hal~de deposition along lcositetr&-
S hedral crystal face~. As silver halide precipitationcontinue~ icositetr~hedral crystal faces first become
identifiable and then expand in area until eventual-
lyt if precipitation is continued, they account for
all of the crystal fsces of the silver halide grains
being grown. Since icositetrahedral crystal faces
accept additional silver halide deposition at a slow
rate, renucleation can occur, creating a second grain
population. Precipitation conditions can be ad~usted
by techniques generslly known in the art to favor
lS either continued grain growth or renucleation.
Failure of the art to observe icositetrahe-
dral crystfll faces for silver halide grains over
decades of intense inve~tigation as evidenced by
published silver halide crystallographic studies
suggests that there is not an extensive r~nge of
conditions that favor the selective retarding of
silver halide deposition slong icositetrahedral
crystal faces. It has been discovered that growth
modifiers can be employed to retard silver halide
deposition ~electively at icositetrahedral crystal
faces, thereby producing these ico~itetrahedral
crystal faces a5 the external surface~ of the silver
halide graLns being formed. The growth modifiers
which have been identified are organlc compounds.
They are believed to be effective by reason ~f
showing an adsorption preference for a icositetrahe-
dral crystal face by reason of its unique arrangement
of silver and halide ions. Growth modifiers that
have been empirically proven to be effective in
producing icositetrahedral crystal faces are
described in the examples, below.
-20-
These ~rowth modifiers are effective under
the conditions of their use in the examples. From
empirical screening of a variety of candidate growth
modifiers under differing conditions of sllver halide
precipitation it has been concluded that mult~ple
parameters must be satisfied to achieve lcositetrahe-
dral crystal faces, including not only the proper
choice of a growth modifier, but also proper choice
of other precipitation parameters identified in the
examples. Failures to achieve icositetrahedral
crystal faces with compounds shown to be effective as
growth modifiers for producing icositetrahedral
crystal faces have been observed when accompanying
conditions for silver halide precipitation have been
varied. However, it is appreciated that having
demonstrated success in the preparations of silver
halide emulsions containing grains with icositetrahe-
dral crystal faces, routine empirical studies
systematically varying parameterq are likely to lead
to additional useful preparation techniques.
Once silver halide grain growth conditions
are satisfied that selectively retard silver halide
deposition at icositetrahedral crystal faces,
continued grsin growth usually results in icositetra-
hedral crystal faces appearing on all the grainspresent in the silver halide precipitation reaction
vessel. It does not follow, however, that all of the
radiation sensitive silver halide grains in the
emulsions of the present invention must have
icositetrahedral crystal faces. For example, silver
halide ~rains having icositetrahedral crystal faces
can be blended with any other conventional silver
halide grain population to produce the final
emulsion. While silver halide emulsions containing
any identifiable icositetrahedral crystal face grain
surface are considered within the scope of this
-21-
invention, in most applications the grains having at
least one identifiable icositetrahedral crystal face
sccount for at least 10 percent of the total grain
population and usually these grains will account for
greater than 50 percent of the total gre~n population.
The emulsions of this invention can be
substituted for conventional emulsions to sstisfy
known photographic applications. In addition, the
emulsions of this invention can lead to unexpected
photographic advantages.
For example, when a growth modifier is
pre~ent adsorbed to the icositetrahedral crystal
faces of the grains and has a known photographic
utility that ~s enhanced by adsorption to a grain
surface, either because of the more intimate
assoclation with the grain surface or because of the
reduced mobility of the growth modifier, improved
photographic performance can be expected. The reason
for this is that for the growth modifier to produce a
icositetrahedral crystal face it must exhibit an
adsorption preference for the icositetrahedral
crystal face that is greater than that exhibited for
any other possible crystal fffce. This can be
appreciated by considering growth in the presence of
an adsorbed growth modifier of a silver halide graln
having both cublc and lco~itetrahedral crystal
faces. If the growth modlfier shows an adsorption
preference for the icositetrahedral crystal faces
over the cubic crystal faces, deposition of silver
and halide ions onto the icositetrahedral crystal
faces is retarded to a greater extent than along the
cubic crystal faces, and grain growth results in the
elimination of the cubic crystal faces in favor of
icositetrahedral crystal faces. From the foregoing
it is apparent that growth modifiers which produce
icositetrahedral crystal faces are more tightly
~ 7
-22-
adsorbed to these grain surfaces than to other silver
halide grain surfaces during grsin growth, and this
enhanced sdsorption carries over to the completed
emulsion.
To provide an exemplery photographic
application, Locker U.S. Patent 3,989,527 describes
improving the speed of a photographic element by
employing an emulsion containing radiation sensitive
silver halide grains having a spectral sensitizing
dye adsorbed to the grain surfaces in combination
with silver halide grsins free of spectral sensitiz-
ing dye having sn average dismeter chosen to maximize
light scattering, typically in the 0.15 to 0.8 ~m
range. Upon imagewise exposure radlation striking
the undyed grains is scsttered rather than being
absorbed. This results in an increased amount of
exposing radiation striking the radiation sensitive
imaging grains having a spectral sensitizing dye
adsorbed to their surfaces.
A disadvantage encountered with this
approach has been that spectral sensitizing dyes can
migrate in the emulsion, so that to some extent the
initially undyed grains adsorb spectral sensitizlng
dye which has migrated from the initially spectrally
sen~itized grains. To the extent that the initially
spectrally senaitized grains were optimally sensi-
tized, dye migration away from their surfaces reduces
sensitization. At the same time, adsorption of dye
on the grains intended to scatter imaging radiation
reduces their scettering efficiency.
In the examples below it is to be noted that
a specific spectral sensitizing dye has been
identified as a growth modifier useful in forming
~ilver halide grains having icositetrahedral crystal
faces. When radiation sensitive silver halide grains
having icositetrahedral crystal faces and a growth
~ 7
-23-
modifier spectrsl sensitizing dye adsorbed to the
icositetrahedral crystal fsces are substituted for
the spectrslly sensitized silver halide grains
employed by Locker, the diqadvantageous migration of
dye from the icositetrahedral crystal faces to the
silver halide grains intended to scstter light is
reduced or eliminated. Thus, an improvement in
photographic efficiency can be realizPd.
To illustrate another advantageous photo-
graphic application, the layer structure of a
multicolor photographic element which introduces dye
image providing materials, such as couplers, during
processing can be simplified. An emulsion intended
to record green exposures can be prepared using a
growth modifier that is a green spectral sensitizing
dye while an emulsion intended to record red
exposures can be prepared using a growth modifier
that is a red spectral sensitizing dye. Since the
growth modifiers are tightly adsorbed to the grains
~nd non-wandering, instead of coating the green and
red emulsions in separate color forming layer units,
as is conventional practice, the two emulsions can be
blended and coated as a single color forming layer
unit. The blue recording layer can take any
conventional form, and a conventional yellow filter
layer can be employed to protect the blended green
and red recording emulsions from blue light expo-
sure. Except for blending the green and red
recording emulsions in a single layer or group of
layers di~fering in speed in a single color forming
layer unit, the structure and processing of the
photographic element is unaltered. If silver
chloride emulsions are employed, the approach
described above can be extended to blending in a
single color forming layer unit blue, green, and red
recording emulsions, and the yellow filter layer can
~'~81~;~7
-24-
be elimi~ated. The advantage in either case is a
reduction in the number of emuls~on layers required
AS compared to a corresponding conventional multi-
color photogrsphic element.
In more general applications, the substitu-
tion of an emulsion according to the invention
containing a growth modifier spectral sensitizing dye
should produce A more invariant emulsion in term~ of
spectral propertles than a corresponding emulsion
conta~ning silver halide grains lacking icositetrahe-
dral crystal faces. Where the growth modifier is
capable of inhibiting fog, such as 2-methyl-5-nitro-
l-H-benzimidazole, 2-mercaptoimidazole, or 7-ethoxy-
carbonyl-6-methyl-2-methylthio-4-oxo-1,3,3a,7-tetra-
azaindene, shown to be effective growth modifiers inthe exsmples, more effective fog inhibition flt lower
concentrations may be expected. It is recognized
that a variety of photographic effects, such as
photographic sensitivity, minimum background density
levels, latent imsge stability, nucleation, develop--
ability, image tone, absorption, and reflectivity,
are influenced by gr~in surface interactions with
other components. By employing components, ~uch as
peptizers, silver halide solvents, sensitizers or
desensitizers, s~persensit$zers, halogen acceptors,
dyes, antifoggants, stabilizers, latent image keeping
agents, nucleatlng sgents, tone modifiers, develop-
ment accelerators or inhibitors, development
restrainers, developing agents, and other addenda
that are uniquely matched to the icositetrahedrsl
crystal surface, distinct advantages in photographic
performance over that which can be realized with
silver halide grains of differing crystal faces are
possible.
~5 The silver halide grains having icositetra-
hedral crystal faces can be varied in their proper-
~81'~7
-25-
ties to satisfy varied known photographic applications
as desired. Generally the techniques for producing
surface latent image forming grains, internal latent
image forming grains, internally fogged grains,
surface fogged grains, and blends of differing grains
described in Research Disclosure, Vol. 176, December
1978, Item 17643, Section I, can be applied to the
preparation of emulsions according to this invention.
Research Disclosur~ is published by Kenneth Mason
Publications, Ltd., Emsworth, Hampshire P010 7DD,
England. The silver halide grains having hexocta-
hedral crystal faces can have silver salt deposits on
their surfaces, if desired. Selective site silver
salt deposits on host silver halide grains are taught
by Maskasky U.S. Patents 4,463,087 and 4,471,050.
The growth modifier used to form the
hexoctahedral crystal faces of the silver halide
grains can be retained in the emulsion, adsorbed to
the grain faces or displaced from the grain faces.
For example, where, as noted above, the growth
modifier is also capable of acting as a spectral
sensitizing dye or performing some other useful
function, it is advantageous to retain the growth
modifier in the emulsion. Where the growth modifier
is not relied upon to perform an additional useful
photographic function, its presence in the emulsion
can be reduced or eliminated, i~ desired, once its
intended function is performed This approach is
advantageous where the growth modifier is at all
disadvantageous in the environment of use. The growth
modifier can itself be modified by chemical
interactions, such as oxidation, hydrolysis, or
addition reactions, accomplished with reagents such as
bromine water, base, or acid - e.g., nitric,
hydrochloric, or sulfuric acid.
-26-
Apart from the novel ~r&in ~tructures
identi~`ied ahove, the radiat{on ~ensitive silver
halide emulsions and the photographic elements in
which they are incorporated of thi~ invention csn
take any convenient conventional form. The emulsions
can be washed a~ described in Re~esrch Disclosure,
Item l-/643, cl.ted above, Section II.
The radLatlon sensitlve ~ilver halide grsins
of the emul~ions can be surface chemically ~ensi-
t.lzed. Noble metal (e.g., gold), middle chalcogen(e.g., sulfur, selenlum, or tel.lurium), and reduction
~ensltlzer~, employed i.ndividually or in combination
are speclficall.y contempl.ated. Typical chemical
sensitizers are listed in Research Di~closure, Item
17643, clted above, Section III. From comparisons of
surface halide and silver ion srran~ements in general
the chemical ~ensitIzation response of silver halide
RraLns havin~ tcositetrshedral crystal faces should
be analogou~, but not identical, to that of cubic and
octehedrel ~ilver halide grains. That ob~ervatlon
can be extended to emulsion addenda generally which
adsorb to 8rain ~urfaces.
The si.lver halide emulsion~ can be qpectral-
ly sensitlzed with dyes from fl v~riety of cl~ses,
includlnp, the polymethlne dye class, which includes
the cysnlnes, merocyanlnes, complex cyanine~ and
merocyanlne~ (i.e., tri-, tetra-, and polynuclear
cyanl.nes and merocyanines), oxonols, hemioxonols,
styryls, merostyryls, and ~treptocyanines. Illustra-
tlve spectral sen~itl.zin~ dyes are disclosed in_searc}l _I.sclosure, Item 17643, cited above, Section
IV.
The ~.llver halide emulsions AS well as'other
layers of the photographic elements of thi~ invention
can contain as vehicle~ hydrophilic colloids,
employed alone or in combinstion with other polymeric
materlals (e.g., latt.ices). Suitable hydrophilic
~.2~3~Z~7
materisls include both natur*lly occurring ubstances
such as protelns, protein derivstives, cellulose
derlvatives -e.g., cellulose esters, gelstin -e.g.,
alkali treated gelatin (cattle, bone, or hide
eelatin) or acid treated gelatin (pigskin gelatin),
gelQtin derivatives -e.g., acetylated gelstin,
phth~lated gelatln, and the like, polysaccharides
such as dextrsn, gum srablc, zein, ca~ein, pectin,
collagen derJ.vatives, collodlon, sgar-sgar, arrow-
root, and slbum:l.n. It ls speci.ficslly contemplatedto employ hydrop}ll.llc colloids whi.ch contain a low
proportlon dlvalent sulfur atoms. The proportion of
divalent sulfur stoms can be reduced by treatin8 the
hydrophLl.ic colloid wlth a strong oxidizing agent,
such as hydrogen peroxi.de. Among preferred
hydrophil.lc col.lolds for u~e as peptizers for the
emul.sions of thi.s lnvention sre gelatino-peptizers
which contain less than 30 micromoles of methionine
per gram. The vehicles can be hardened by
conventional procedures. Further details of the
vehicles and hardeners are provided in Research
Dlsclosure, Item 1764~, cited above, Sections IX and
X.
The sil.ver halide photo~raphic elements of
thls invention csn contain other sddends conventional
in the pht)togrsphic art. Useful addenda are
descrJ.bed~ for example, In Research Disclosure, Item
17643, c:lted sbove. Other conventional useful
addentia Include antifoggants and stabilizers,
couplers (such ss dye forming couplers, masking
couplers and DIR coupl.ers) DIR compounds, ant~-stain
~gents, lmage dye stabi.lizers, absorbing materials
such as filter dyes and UV absorbers, light scatter-
i.ng materlals, antistatic agents, coating sids, snd
plasticizers ~nd lubricants.
The photographic elements of the present
inventlon can be si.mpl.e black-and-white or monochrome
~a~
-28-
elements comprising B support bearing a layer of the
silver halide emul~ion, or they csn be multil~yer
and/or multicolor element~. The photographic
elements produce lmagea r~nging from low contrQRt to
very hig}l contra~t, such as those employed for
producine half tone imsges ln grsphic arts, They can
be de~lgned for proce~Ring with ~epar~te solutions or
for in-camera proce~ing. In the latter instRnce the
photographLc elemen~s can include conventional imsge
tran~fer features, such as those illustrated by
Research ~lRclosure, Item 17643, cited sbove, Section
XXIII. Multi.color elements contain dye image forming
unlts sen~:Ltlve to esch of the three primary regions
of the spectrum. Each unit c~n be comprised of ~
single emulslon l~yer or of multiple emulsion layers
sensltlve to a gLven re~i.on of the qpectrum. The
layers ot' the element, lncl.uding the layers of the
imap,e forming units, c~n be arranged in various
orders as known in the a~t, In an alternative
format, the emulsion or emulsions c~n be dispo~ed as
one or more ~eemented layers, e.g., QS by the use of
mi.crovessels or microcells, QS de~cribed in Whitmore
U.S. Psten~ 4,387,154.
A preferred multicolor photo~r~phic element
sccording to this invent10n containing incorporated
dye imaRe provldi.ng m~teri.als comprlses a support
be~r.lng ~t least one blue sensl.tlve sllver hallde
emulsJ.on layer havlne associated therewlth ~ yellow
dye formlng coupler, at lea~t one green sensitive
sl.lver halLde emul.si.on layer havlng associated
therewith a magenta dye formi.ng coupler, and &t least
one red sensltlve sllver halide emulslon layer havlng
assoclsted therewith a cyan dye forming coupler, at
least one of the sllver halide emulsion lsyers
contalning grains having icosLtetrahedral crystal
faceR as previou~ly described,
8~ 7
-29-
The e].e~ents of the present invention can
contsin sddltlonal layers conventional in photo-
graphic elements, such as overco~t layers, spAcer
layers, fllter layers, antihalation layers, and
scavenger layers. The support can be any suitable
support used wlth photograph~c elements. Typ~cal
supports 3.nclude polymerlc films, paper (including
polymer-coated paper), glass, and metsl supports.
Details re~srdi.n~ supports and other layers of the
photo~raphic elements of this invention are contained
in Rese rch Dlsclosure, Item 17643, cited ~bove,
Section XVII.
The photoF,raphic elements can be im&gewise
exposed wi.th var:Lous forms of energy, which encompass
the ultravlolet, vlslble, and infra~ed re~ions of the
el.ectromap,netlc spectrum as weJ.l as electron beam and
beta rAdlat:lon, gamma ray, X rsy, alpha particle,
neutron rsdiati.on, and other forms of corpuscular and
wave-like radiant ener~y in either noncoherent
(random phase) forms or coherent (in phase) forms, as
produced by lasers. When the photographic elements
are intended to be exposed by X rays, they can
include ~eatures found in conventional radiogr~phic
elements, ~uch ~s those illustrated by Research
Dlsclosure, Vol 184, Au~ust 1979, Item 18431.
Processing of the imagewise exposed
photo~rsphlc el~ments can be ~ccomplished in any
convenient conventional manner. Processing proced-
ures, developirlg a~ents, and development modifiers
sre lllustrated by Research Dlsclosure, Item 17643,
cLted ahove, Secti.ons XIX, XX, and XXI, respectively.
ExamPles
The :I.nventlon c~n be better appreciated by
reference to the foll.owine specific examples. In
each of the examples the term "percent" means percent
by weJ.F,ht, unless otherwise indicated, and all
solutlons, unl.ess otherwise indicated, are aqueous
~'~ 8
-30-
solut1Ons. Dllute nitric acid or dilute sodlum
hydroxlde was employed for pH ad~ustment, ~9 required.
ExamPle
This example illustr~tes the preparation of an
icositetrshedral ~5.1.ver bromide emulsion having the
Mlller tndex {21.1), beginning with a cubic host
emulsion and usLng as erowth modifier Compound I.
~3=~ T - CH2CH
\-=-/ \S--~
c~3 S
Compound I
To a resction vessel. supplied with a stlrrer
wss sdded 0.05 mole of a cublc ~ilver bromide
emulsl.on of mean p,r~.n size 0.8~m, containing Rbout
10 g/Ag mole of gelstln. Wster was edded to mske the
total we:L~ht 50 8- To the emulsi.on st 40C was added
2.0 mill1mole/Ln1tL~l Ae mol.e o~ compound I dissolved
in 2 mL. of methanol and 2 drops of triethylamine.
The emuls~.on wss then held for lS min. ~t 40C. The
pH was adJusted to 6.0 at 40C. The temperature W8S
rsi.sed to 60C, snd the PAe sdJusted to 8.5 at 60C
wLth KBr and mslntslned st thst value during the
preclpttstLon. A 2.5M sol.ution of AgNO~ wa~
lntroduced at a constant rste over R period of 125
mtn. wh.lle a 2.5M sol.utlon of KBr wss sdded 8S needed
to ho1.d the pA~ constsnt. A total of 0.0625 mole Ag
WQS added.
A csrbon replS.cs el.ectron microgr~ph (Figure
12) shows Emulsion l to have 5.cos~tetrshedral faces.
The Mill.er lndex of the lcosttetrahedral faces was
determi.ned by measurement of the relative angle
between two sdJacent Lcosltetr~hedral crystal faces.
From th:l.s snp,le, the suppJ.ement of the relstive
angle, whlch is the angle between their respective
crysta].lographic vectors, ~, coul.d be obtained, ~nd
the Mlller index of the sdjscent icositetrshedral
~8~ 7
-31-
crystal f~ces was ldentlfied by comparison of this
sngle ~ wlth the theoretical intersecting angle
between [hlQlQl~ and rh2Q2Q23
vectors. The sngle ~ W8S cslculsted as described
by Phlllips, clted above, at psges 218 and 219.
To obtsin the sngle ~, a carbon replics of
the crystal qsmple WR4 rotated on the stsge of ~n
electron microscope until, for ~ chosen cryst~l, the
angle of observation ws4 directly slong the line of
intersectLon of the two sd~acent crystal faces of
lnterest. An e1ectron mi.crogrsph was then msde, ~nd
the relst:lve angle was me~sured on the microgrQph
wtth a protr~ctor. The supplement of the measured
relstive sngle was the angle ~ between vectors.
Compsrl40n of ~ wlth ~ enabled the crystal fAces
to be asslgned. If the experiment~lly determined
sngle wa~ nearl.y mid-w~y between two theoretical
sngles, the one sssocl.ated wlth the lower Miller
~ndex was used for the assi~nment. The re~ults for
Emulslon 1 sre summarized i.n Table I. The number of
measurements msde ls given in psrentheses. Theoreti-
cal vsl.ues for vectors up to {544} were
considered.
ExsmPle 2
Ttli4 example il.lustrAtes the prep~r~tion of
sn ico~itetrahedrsl silver bromide emulsion hsving
the Mller lndex ~211}, beginning wlth a cubic
host emulsion, and usin~ Compound II ss a growth
modifier.
H2~ T--Et
CH~
Compound II
Th:ls emuls10n was prepared ss described for
Exsmple 1, except that the growth modifier w~s 2.0
~2~7
-32-
ml.lllmole/Ag mole of Compound II, dls~olved in 3 mL.
N,N-dlmethylformamlde. The preci.pitstion was carried
out for 100 mLn., consumine 0.05 moles Ag. An
electron mlcro~raph of the resulting ico~tetrshedral
S emulston gralns ~s shown In Figure 13. The Miller
Index was determS.ned to be j211} by the me~Qure~
ment~ ted ln ~able I, using the method described
for Example l.
ExsmPle 3
Thi.s example Lllustrates the preparation of
sn icositetrshedrsl sllver bromide emulsion having
the Miller index {211}, beginning with a cubic
host emu1.s~on and using 4-hydroxy-6-methyl-2-methyl-
mercapto-1,3,3a,/-tetrazaindene (Compound III) a5 a
growth modifier.
To a resctlon vessel. supplied with a stirrer
wsq sdded 0.4 g of de.lonized bone gelatin dissolved
in 24 g o~` water. To thi~ was added 0.04 mole of a
cublc si.lver bromlde emuls3.on of mean grain size
0.8~m, containlng 10 e/Ag mole gelatin and having a
total weight of 15.7 e. The mixture was heated to
40C, and 6 millLmoles/Ag mole of Compound III were
added, dissolved in 3 ml,. water and 3 drops triethyl-
amine. The resultlng mtxture was held for 15 min. st
40C. The pl~ wss ad~usted to 6.0 at 40C. The
emulsion wa9 then heated to 60C, the pAB sd~usted to
8.S at 60DC with KBr, and maintained at that value
durlng the preciplt~ton. A 2M solution of AgN03
was lntroduced over a perlod of 100 min. at a
constant rste, whlle a 2M solution of KBr wss added
as needed to hold the PAR con~tant. A total of 0.04
mol.e Ag wa~ added.
An elect~on m.l.crograph of the resultin~
Lcositetrahedra1. emulsion gralns is shown in Figure
J.4. The Mlller index was determined to be {2111
by v:i.Qus1. comparl~on with an accurate model of a
{211} lcositetrshedron.
8 ~ 7
-33-
ExamPle 4
Thl~ exsmple .I.I.lust~te~ the prepar~tlon of
an Lco~ltetr~hedrsl ai.lver bromIde emulAion hsving
the M.Lller index {211~, beglnning with a cubic
host emut~ton and u~ing Compoun~ IV as 8 growth
modifier.
i~ \[/ \ ~ CH2CH2503H
Compound IV
The emulsLon was prepsred ss de~cribed for
Exsmple 1, except thst the growth modifier was 2.0
mllllmole/Ag mol.e of Compound IV, di~solved in 6 mL.
ot` N,N - dimethylformsmlde, 1.5 mL. of wster, ~nd 3
drops of trlethylsmlne. The precipitstion was
carried out for 100 mi.n., consuming 0.05 mole Ag.
An electron mlcrogrsph of the re~ultin~
lcosltetrahedrsl emulsion 8rsins is 3hown in Figure
lS. The Miller :Index wa~ determined to be ~211~
by the me~urements lI~ted ln Tsble I, using the
methods descri.bed for Example 1.
ExamPle 5
Thls example lll.ustrste~ the prepsr~tion of
an icosltetrshedral. si.lver bromlde emulsion hsving
the Mlller lndex ~211~, beginning with a cubic
ho~t emulsion, snd usi.ng Compound V as a growth
modifier.
.~ \./S \ ~ -Et
I! /'=-\ !
Et
Compound V
Emul~ion Exsmple S w~ prepared aq de~cribed
for Exsmple 1, except for the following changes: The
.~81ZZ7
-34-
growth modifier was 2.0 mi.llimole/Ag mole of Compound
V, dissolved in 3 ml.. of N,N-dimethylform~mlde. The
prec.LpitstLon was carried out usLng 2.OM AgN03 and
2.0M KBr, :In two stages. In the first stage, the
AgN03 sol.utl.on w~s sdded over 8 period of 75 min.,
consumi.ng 0.03 mole Ag. In the second stsge the
AgN03 addltlon rate wss hslved, so thRt Rn
Rddltional 0.01 mole Ag was added over a period of 50
min. The pAg was maintRined at 8.5 throughout by
addi~ion of the KBr solutlon as described for Ex~mple
1.
An electron micrograph of the resulting
icositetrRhedral emul.sion gralns is shown in Figure
16. The Mtller ~ndex W8S determined to be {2ll~
by the measurements 11.sted in Table I, using the
method described for Example l.
Exsmple 6
Th.Is example illustrates the preparation of
an .i.cosltetrshedral sil.ver bromide emul~ion having
t}~e Mi3.1er index {21l~, be8inning with ~n
octahed~al host emulslon and using 2-methyl-5-nitro-
lH-ben~imldazole (Compound VI) as the growth modifier.
The emulsIon was ~repared as described for
Example l, except ~or the fol.lowing changes: The
host emu].s1.on was 0.05 mole of an oct~hedral silver
bromlde emulsion of mean grQl.n slze O.8~m. The
growth modifler was 6.0 millimole/initial Ag mole of
Compound VI disso1.ved in 3 mL. methanol. The
precipitatton was over a period of lOO minutes
consuming 0.05 moles Ag.
An electron microgr~ph of the resulting
icosltetrahedral emulsion grains is shown in Figure
l~. The Miller 1.ndex W8S determined to be ~2ll)
by tSIe measurements ].isted in Table I, using the
metS1od described for Example l.
Example 7
This example il.lustrates the preparation of
an i.cosItetrahedral sllver bromide emulsion having
1'~81'~7
-35-
the Miller index {211~, beginning wi~h a cubic
ho~t emul.si.on, using a~ growth modifier Compound VII,
and wlth ammoni.~ pre~ent durLng the shell precipi-
tstion.
0 ,H
H03SCH2--C112~ \C6H5
Compound VlI
To a reactlon ves~el supplled with a stirrer
wa~ added 1.0 g of deionlzed bone gelatin dissolved
in 27 S g of wster. To this w~s ~dded 0.05 mole of a
cubic sllver bromlde emulsion of mesn grsin size
0.8~m, containing sbout 10 g/Ag mole of gelstin snd
having A totsl weight of 21.6 8- The emulsion was
hested to 40C, snd 2.0 mlllimole/initisl A8 mole of
Compound VII were sdded, di~solved in a 2.5 mL.
portion of a 301vent prepsred from 18 mL. N,N-di-
methylformamLde, 2 ml. wster ~nd 1 drop of triethyl-
~mlne. The mlxture wss hel.d st 40C for 15 min.
Just prior to begi.nning the precipitstion3.'~ mllllmoles of sn AqueOU3 (NH4)2SO4 qolution
(1.0 ml.), contslninP~ ~lso 0.25 mlllimoles of KBr, was
added, followed hy 25.9 millimoles of ammonlum
hydroxlde (~..0 mL). The PAe wss messured ss 9.2 st
40~C, and was ms.Lntsined through the precipi-
tst:l.on. At 40C a ~..5M solutlon of AgN03 was sdded
st a constsnt flow rste slonp, with 8 2.5M solution of
KBr 8~ necesssry to msintsin the pAg. THe precipit~-
tion consumed 0.05 mole A~ over 8 period of 100 min.The pH WAS then slowly AdJusted to 5.5.
An electron micro~rsph of the resulting
icositetrahedrsl emulsion grains i~ ~hown in Figure
18. The Mil.ler index wa~ determined to be ~211}
by the measurement~ liqted in Tsble I, u~ing the
method de~cribed for Exsmple 1.
~;~ 8~
-36-
ExamPle 8
This example Lllustrates the preparation of
an ico~itetr~hed~al silver bromide emulsion using a
cubic host emul~ion ~nd Compound VII 89 growth
modifier, as in Example ~, but in the sbsence of
ammoni.s durtng the preclpitstion of the outer portion
(l.e,, shell) of the grai.ns. The resulting grains
showed 8 M.Lller lndex of {311} 8S compared to the
{211~ .Lndex of the grains prepared in the
presence of ammonia.
To a resctlon ve~sel supplied with Q stirrer
wss sdded 0.04 mol.e of a cubic silver bromide
emu1.sion of mean graln slze 1.8~m, contsining ~bout
lOg/Ag mole gelatin. The emulsion wss diluted with
distlJ.led wster to a tota1. weight of 40 grams. KBr
solutlon (0.5 ml.) wss sdded to bring the bromide
concentrstion of the emulsion tn the resction vessel
-3
to 5 x 10 M. The emul.sion W8S heated to 40C, snd
l.5 millimoles/Ag mole of Compound VII were sdded,
dlsso1ved in 1 mL. of a solvent prepared from l3 mL.
N,N-dimethylformamide, 2 mL. wster, and 2 drops of
trlethylamine. The mixture was held for 15 min. at
40C. The pH W8S ad~usted to 6.0 st 40C. The
emulsion was then heated to 60C. The pAg was
sdJusted to 8.5 at 60C with KBr and msintained at
thst v~1ue durlnp, the prec1.pitatlon. A 2M solution
of AgN03 wss lntroduced over a period of 123 min.
at a constsnt ~ste, while 8 2M solution of KBr WRS
added as needed to hold the pAg constant. A totsl of
0.02 mole Ag was added.
Two scsnnlng electron microgrsphY of the
resultlng icositetrshedr~l emulslon grains are shown
in Fi.gures 19A snd l9B. The Miller index was
determined to be {311~ by the measurements listed
in Tsble I, uslng the method described for Exsmple 1.
_8mP 1 e 9
Thi.s emulsion illustrates the preparstion of
sn icositetrahedra1. silver bromide emulsion having
-37-
the Mil1.er index l311}. beginning with a cubic
lloRt emulsion, using Compound VIII R~ the growth
mod.Lfier, ~nd w~th ~mmoni~ present during the
preclpitstlon of the outer portion of the grain.
Th IQ emu].si.on w~s prepared a3 described for
Example 7, but with the followi.ng differences: The
deionlzed bone gel~tin w~s omitted from the starting
solution. The growth modifler was 3.0 millimole/Ag
mole of Compound VIII dl~qolved i.n 3 mL methsnol and
2 drops of triethyl~mine. The pAg prior to the
preclp.ltat~.on was messured as 9.4 ~t 40C end
ma.i.nt~lned ~t thst vRlue durl.ng the precipitation.
~-\ /O \ ~ CH-co2H
I ll =CH-CH= \S T
~./ \ ~ ~S 3
C2H5
Compound VIII
An electron m~crogr~ph of the resulting
LcositetrQhedr~l emul.qion gr~ins is shown in Figure
20. By visu~1. comp~rison of the mlcrogrsphs with ~n
sccur~te model, the Miller index was determined to be
{311}.
Example lO
~hls ex~mple i.1.1uQtr~tes the prep~r~tion of
~n lcosltetrshed~l silver bromide emulsion h~ving
the Mlller lndex {311}, begi.nning with a cubic
host emulslon and using Compound IX ~s the growth
modifier.
`? S T
CH2CH2CH3
Compound IX
Thls emulsion W8S prepared ~s described for
Ex~mple 1, but using 2.0 millimole/A~ mole of
-38-
Compound IX as ~ growth modifier, dissolved in 3 mL.
N,N-~lmethyl.form~mide. The precipitation time was
l00 min., consuming 0.05 mole Ag.
An electron micrograph of the resulting
ico~itetrahedral. emu1.sion grains is shown in Figure
21. The Mil.ler index W8S determined to be ~3ll~
by the messurement~ listed in Table I, using the
method descr~bed for Example l.
Example ll
This emulsion illu~trates the prepsrQtion of
silver bromide icositetr~hedral emulsion hAving a
{311~ Mll1.er index by the Ostwald ripening of ~
~msll ersl.n slze AgBr emu1.sion onto a mixture of
cubic snd octahedrsl host gralns in the presence of
Compound X actlng ag a growth modifier.
C02C2H
~C I 5
~ i/ \ ~ \ -SCH
0
Compound X
To a reaction vessel were added 32.5 8 (7-5
millimole) of a fre~hly prepsred AgBr Llppmann
emul.slon of mean grain size 6pproxim~tely 0.02~m
contalnlng 167 g/Ae mole of gelatin. At 35C, 0.09
milJ.imole of Compound X wa9 added, dissolved in l mL
methanol ~nd l mlJ N,N-dtmethylformsmide. Then 3.0
ml., 7.5 ml1.llmo1.e of AgBr consistlng of a m1xture of
two emulsLons cont~lning approximately equal numbers
3 ol: cubes (0.8llm mean grain size; l0 gtAg mole
~elat.l.n) snd octahedrs (0.81lm mean grain size; l0
g/A~ mole gelstin) were added. The pH was ~d~usted
to 6.0 at 40C, and the pAg to 9.3 with KBr solu-
tion. The mlxture was then he~ted to 60C, ~nd
~llowed to stir ~t thst temperature for l9 hrs.
Figure 22 ls an el.ectron micrograph of the
resulting emulsion, show.5.ng the cryst~ls to have an
8~Z'~7
-39-
icositR~rahedr~l. habit. The Miller index W8S
determined to be ~311] by vi~ual comp~ri~on with
an accurate model of a regular {311} ico~i-
tetrahedron.
S ExamPle 12
Thl~ example lllustrates the preparation of
a ~ilver bromide icositetrahedral emulsion having
{533~ Miller index crystal. faces, using a cubic
host emul3lon and Compound XI, 2-mercsptoimidazole as
0 8 growth modifier.
The emul.si.on was prepared 85 described for
Example l, but using 6.0 mllllmolelAg mole of
Compoun~ XI as growth modtfier, dissolved in 3 mL.
methanol. The preclpltatlon time was 100 min.,
consumlnR O.OS mole Ag.
An electron micrograph of the resulting
icosi.tetrahedral emuls:lon grains iq shown in Figure
23. The Miller J.ndex was determined to be ~533}
by the measurement~ llsted in Tsble I, using the
method de~cribed for Example 1.
ExamPle 13
This example lllustrate~ the preparation of
an icosltetrahedral silver chloride emulsion having
{21l~ Mil.ler lndex c~ystal faces, using a cubic
si.lver chloride host emulsion and Compound VI as the
growth modi.~ier. It is to be noted that the same
Mi.ll.er lndex c~ystal faces were obtained when this
p~rowth modlfier was used to prepare the silver
bromi.de emulsion of Exsmple 6.
To a reaction vessel qupplied with a stirrer
wsq added 0.05 mole of a cubic silver chloride
emulslon of mean g~ai.n si7e 0.65~m contsining 40
g/Ag mole gelatin. Water was added to make the total
weJ.ght 48 g. To the emulsion at 40C were added 6.0
milll.mole/Ag mole of Compound VI dlssolved in 3 mL.
methanol. The emulsion wa~ held 15 min. at 40C.
The temperature was then raised to 50C. The pH w~s
-40-
adJu~ted to 5.93 at 50~C and m&lntained ~t sbout thi~
value dur.lnK the precipitation. The pAg wa~ ad~usted
to 7.7 at 50C wittl NaCl ~olut$on and m~intained at
that v~lue dur.l.ng the precipitation. A 2.5M solution
S of AgNO3 ws~ Introduced at a constsnt rate over a
period of 125 min., whlle a 2.7M ~olution of NaCl was
added as needed to hold the pAg constant. A total of
0.0625 mole Ag was added.
An electron micrograph of the resulting
ico~itetrahedra1. emulsion grains is shown in Figure
24. The Mll.ler index was determined to be {211}
by the meQsurements ll.~ted ln Table I, using the
method descri.bed for Example 1.
ExamPle 14
This example ill.ustrates the preparation of
an .Lcosltetrahedral sllver chl.oride emul9ion havin8
the Mlller lndex {522}, making use of Compound I
a9 the g~owth mod:l.f.ler. It Is noted that the use of
Compound I ~esulted ~n an index of {211} in the
c&se of the ~llver hromide emulsion of ~xample 1.
The emulsi.on was prepared by a procedure
simllar to that descrlbed in Example 13, but with the
following change~: The 8rowth modifier was 2.0
mllli.moles/Ae mole of Compound I, dissolved in 2 mL.
methanol and 2 drops of trLethylamine. The pH was
mai.ntained at 5.92 at 50C, and the pAg was main-
ta~ned ~t 7.9 during the precipitation.
An electron mlcrograph of the resulting
icositetrAhedral emulsion grains is ~hown in Figure
25. The Mll~.er index was determined to be 1522}
by the measurement3 l~ted in Table I, using the
method described for Example 1.
ExamPle 15
Thls example tllustrates the preparation of
an lcos1tetr~hedrsl ~ilver bromoi.odide (3 mole
I.odi.de~ emulsion havl.ng the Ml.ller index {211~,
employLne a cubic ABB~I host emulsion and Compound VI
as growth modifier.
l ~lZ'~7
-41-
To a reactlon ve~el supplied with a stirrer
was added 0.05 mole (50 B) of a cubic ilver
bromoiodlde emulsion, of mean grain 3ize 0.6~m,
cont,alnLng 3 mole % lodide and 30g/Ag mole gelatin.
To the emulsion at ~0C were added 6.0 millimole~/Ag
mole of Compound VI dissolved in 3 mL. methanol, The
emul~lon was held 15 min. at 40C. The temperature
was then raised to 60C. The pH was ad~u ted to 6.0
at 60C and malntained at that value. The pAg was
adJusted to ~.5 wit,h K~r and maintsined st 8.5
throughout the ~recipitation. A 2.5M solution of
AgNO3 W8S Lntroduced at a constant rate over a
period of 250 min., while 8 solutlon which was 2.43M
In KBr and 0.0/M in KI W89 sdded as needed to hold
the pAg constant. A total of 0.0625 mole Ag was
added.
An electron mlcrograph of the resulting
Icositetrahedral emul31On 8rain~ i~ shown in Figure
26. The Mlller Lndex W8S determined to be {211}
by visual compsrI30n w~th an accurate model of a
reRular {211~ icositetrahedron.
Example 16
This example illustrates the preparation of
an icositetrahedral sIlver bromoiodide (3 mole %
lodlde) emu1sion having the Miller index {211~,
employlne a cublc Ae8rI host emulsion and Compound I
a9 a growth modifier.
This emu1sLon was prepared by the procedure
described for Example 15, but using 3.0 millimoles/Ag
mole o~ Compound I as a growth modifier, dissolved in
3 mL. methanol and 3 drops of triethylamine. The pH
was maintained at 5.87 at 60C.
An elect~on micrograph of the resulting
icosltetrahedral emul~ion grains is shown in Figure
2/. The Miller Index was determined to be {211}
by comparlson with an sccurate model of a regular
{2111 lcositetrahedron.
8~ 7
-42-
TABLE I
An~le Measurement Data
Type An~le Between Vectors
Theoretlc~l ~211~ 33.6 48.2
" {311~ 50.5 35.1
" {322l 19.~ 58.0
" {411) 60.0 27.3
" {433} 13.9 61.9
" {511} ~6.0~ 22.2
~ {522~ 43 3 40.8
" {533~ 24.9~ 54.5
" {544~ 10.8 64.0
TABLE I (cont'd)
AnKle Mes~urement Data
15 Exam~ rowth Angle
TY~e ~lide Modl~ier Between Vectors
1 {211} AgB~ I29.2~1.0(3) 51.3+0.8(3)
2 1211} AgBr II33.7~1.3(7) 48.5+0.8(8)
3 {211}* AgBr III
4 {2~} AgBr IV47.4+1.1(5)
{211~ A~Br V50.0+1.4(4)
6 {211} ARBr VI31.0~0.8(4) 49.5+2.6(6)
/ {211~ AgBr VII34.8+1.9(6) 47.2+1.3(9)
8 (3117 ARBr VII48.2+3.5(4) 35.4+1.3(8)
25 9 {3Jl}* AgBr VIII
{311} AgBr IX49.6~0.5(5) 36.0+0.9(8)
11 t3117~ AgBr X - -
t2 {s33? AgBr XI24.0+2.0(4) 53.8+1.8(8)
13 {2111 AeCl VI34.8+1.3(4) 47.2+0.9(6)
30 14 {5227 AgCl I45.8+2.7(5) 38.3+2.4(6)
{21l7* A~BrI VI
16 {211~* AgBrI
* Determinefl by visual comparison with an sccur~te
model of ~ regular icositetrahe~ron of the same
Mlller index
-43-
ExsmPle 17
Thlq example llluqtr~tes addition~l growth
modifiers capsble of producing icositetrahedrsl
c~y~tal fRces and llsts potential growth modifiers
:i.nvestiKat0d, but not obse~ved to produce icositetrs-
hedral crystal faces.
The graln growth procedure~ employed were of
three different types:
A. The fi.~st grain growth procedure was 8S
follows: To a reactlon vessel supplied with a
sti.rrer was added 0.5 g of bone gelatin dissolved in
28.5 g of water. To this was added 0.05 mole of
silver bromide host graln emulsion of mean 8rain ~ize
0.8~m, contalning about lOg/Ag mole gelatin, and
hav.1.ng a total. wetght of 21.6 g. The emulsion was
heated to 40C, ~nd 6.0 millimoles/Ag mole of
dissolved growth modifier were sdded. The mixture
W8S hel.d for 15 min. at 40C. The pH w~s ad~uqted
to 6.0 at 40C. The emulsion wa~ then heated to
60C, and the pAg was ad~usted to 8.5 at 60C with
KBr and maintained at th~t value during the precipi-
tst.lon. The pH, which shifted to 5.92 at 60C, was
held At th~t value thereafter. A 2.5M solution of
AaNO3 and a 2.5M solution of KBr were then
introduced w.lth 8 constant sll.ver addition rate over
a perlod of 125 min., consumtne 0.0625 mole Ag.
B. The second grain growth procedure was
as followq: To 8 reaction vessel supplied with a
stlrrer wes added 27.5 mL of water. To this was
add~d 0.05 mole of a si.lver bromide host grain
emulslon of mean graln size 0.8 ~m, containing
about 10 g/Ag mole of gel~tin and having a totsl
weight o~ 21.6 g. The emulsion was heated to 40C,
and 3.0 mil~.imole/initial Ag mole of dis~olved growth
modifter was added. The mixture wa~ held at 40C for
15 mi.n. Just prlor to beginninB the precipitation
3.4 mll.limoles of an a~ueous (NH4)2SO4 ~olution
:
8~ ~7
-44-
(1.0 mL), contslning ~lso 0.25 millimole of KBr, w~s
~dded, followed by 25.9 mill.imoles of smmonium
hydroxlde (2.0 ml.). The pAg was messured as 9.3 st
40C and was mal.ntalned ~t that level throughout the
precipLtatlon. At ~0C a 2.5M solution of AgN03
was added at R constsnt flow r~te Rlon~ with ~ 2.5M
so1.ution of KBr, the latter being added at the rate
necesssry to ma.lntaln the pAg. The preclpit~tion
con~umed 0.05 mole Ae over 8 perlod of lO0 min. The
pH wa~ then ~lowly ad~u~ted to 5.5.
In the first snd second procedures cubic or
octshedral host graIns were employed hS noted in
Table I. Smsl1. samples of emulsion were withdrawn st
intervsls durlnp, the precipitation for electron
mlcroscope examination, sny tetrAhexAhedrsl crystal
faces revealed ln such ssmp1.es are reported in Tsble
I.
C. The third grain growth procedure
employed 7.5 mi.111moles of ~ freshly prepared very
fine graln (approxJ.mately 0.02 ~m) A8Br emulsion to
which was added 0.09 mllll.mo1.e of growth modifier.
In this process the~e very fine AgBr grains were
d:lssolved and repreclpitated onto the host grains.
The host grsln emulsion contsined 0.8 ~m AgBr
grains. A 7.5 mill.lmole porti.on o~ the host grain
emu1.slon W~9 ~dded to the very eine grRln emulsion.
pH of 6.0 snd pAg of 9.3 st 40 C was employed.
The mlxture was stirred st 60 C for sbout 19 hours.
The crysts1. fsces presented by the host
grslns are as noted i.n Table I. Where both octahe-
drsl and cubic host erains are! noted using the same
growth mod.lfier, a mixture of 5.0 millimoles cubic
gralns of 0.8 llm and 2.5 millimoles of octahedral
grglns of 0.3 llm wss employed giving approximately
the same number of cublc and octahedral host grsins.
In looki.ng st the grsi.ns produced by ripening, those
produced by ripening onto the cubic grsins were
8~2'~7
-45-
resdlly visua11y dl~tinguished, since they were
1arger. Thus, it was pos31b1e in one ripen1ng
process to determine the cryst~1 faces produced using
both cubic and octahedra1 host grain~.
Differences 1.n i.ndtvidual procedure~ ~re
lndlcated by footnote. The {hQQ~ surface column
of Tsb1e II refers to those surface~ which sstisfy
the def:l.nltion above for icositetr~hedr~1 crysts1
faces.
.
1.2~ 7
-46 -
T A B L E II
lhQ~ Host
Growth Modifier Surfaces Grains Method
1 5-Nitro-o-phenyl-
eneguanidine
nitrate None cublc C
2 Citrlc acid, tri-
sodium salt None cubic C
3 5-Nitroindazole None cubic C
None oct~hedral C
4 1-Phenyl-5-mercap-
totetrazoleNone octahedrsl
(1)(2) A
5 5-Bromo-1,2,3-ben- None cubic A
zotriazole None octahedral C
6 6-Chloro-4-nitro-
1,2,3-benzo- None cubic C
triazole None octahedral C
7 5-Chloro-1,2,3-ben- None cubic C
zotriazole None octahedral C
8 5-Chloro-6-nitro-
1,Z,3-benzo-
triazole None cub~c C
9 3-Methyl-1,3-benzo-
thla.zolium ~-
toluene3ul- None cubic C
fonate None oct~hedral C
10 4-Hydroxy-6--methyl-
1,3,3a,7-tetra-
azaindene,
sodlum salt None octahedral C
11 4-Hydroxy-6-methyl-
2-methylmercapto-
1,3,3a,7-tetra-
azaindene 1211} cubic A
~81~27
-47-
T A B L E II (continued)
{hQQ) Host
Growth Modifier Surfaces Grains Method
12 2,6,8-Trichloro- None cubic C
purine None octahedral C
13 2-Mercapto-l-phenyl- None cubic C
benzimidazole None octahedral C
14 3,6-Dimethyl-4-hy-
droxy-1,2,3a,7- None cubic C
tetraazaindene None octahedral C
15 5-Csrboxy-4-hydroxy-
1,3,3s,7-tetra- None cubic C
azaindene None octahedral C
16 5-Cflrbethoxy-4-hy-
droxy-1,3,3a,7-
tetraazaindene None cubic A
17 5-Imlno-3-thiour- None cubic C
azole None octahedral C
18 2-Formamidinothio-
methyl-4-hydroxy-
6-methyl-1,3,3a,7- None cubic C
tetraazaindene None octahedral C
19 4-~ydroxy-2-B-hy-
droxyethyl-6-
methyl-1,3,3a,7- None cubic C
tetraazaindene None octahedral C
20 6-Methyl-4-phenyl-
mercapto 1,3,3a,7- None cubic C
tetraazaindene None octahedral C
30 21 2-Mercapto-5-phenyl- None cubic C
1,3,4-oxadiazole None octahedral C
22 l,10-Dithia-
4,7,13,16-tetra- None cubic C
oxacyclooctadecane None octahedral C
23 2-Mercapto-1,3- None cublc C
benzothiazole None octahedral C
24 6-Nitrobenzimidazole None cubic (3) A
~X8~2Z'7
-48 -
T A B L E II ~continued)
{hQQ} Host
Growth ModifierSurfsce~ Grains Method
25 5-Methyl-1,2,3- None cubic C
benzotriazoleNone octahedral C
26 Vrazole None cubic C
None octahedral C
27 4,5-Dicarboxy-
1,2,3-triazole,None cubic C
monopotassium salt None octahedral C
28 3-Mercapto-1,2,4- None cubic C
triazole None octahedral C
29 2-Mercapto-1,3- None cubic C
benzoxazole None octahedral C
6,7-Dihydro-4-
methyl-6-oxo-
1,3,3a,7-tetra-None cubic C
azaindene None oct&hedral C
31 1,8-Dihydroxy-3,6- None cubic C
dithiaoctane None octahedral C
32 5-Ethyl-5-methyl-4-
thiohydantoinNone cubic A
33 EthylenethioureaNone cubic A
None octahedral A
25 34 2-Carboxy-4-hydroXY-
6-met;hyl-1,3,3a,7-~ None cublc C
tetraazaindeneNone octahedral C
35 Dithi.ourazole None cubic C
None octahedral C
36 2-Mercaptoimidazole {533} cubic A
37 5-Carbethoxy-3-(3-
carboxypropyl)-4-
methyl-4-thia- None cubic C
zoline-2-thioneNone octahedral C
38 Dithiourazole-
methyl vinyl None cubic C
ketone monoadduct None octahedral C
28~ 7
-49 -
T A B L E II (continued)
{hQ~} Host
Growth Modifier Surface~ Gr~ins Method
39 1,3,4-Thiadiazoli- None cubic C
5dine-2,5-dithione None octahedral C
40 4-Carboxymethyl-
4-thiazoline- None cublc C
2-thione None octahedr~l C
41 1-Phenyl-5-selenol-
tetrszole, octahedral
pota~sium salt None (1)(2) A
42 1-Carboxymethyl-5H-
4-thiocyclopenta- None octahedral C
(d~uracil None cubic C
43 5-Bromo-4-hydroxy-
6-methyl-1,3,3a,7-
tetraazaindene None cubic A
44 2-Carboxymethyl-
thio-4-hydroxy-6-
methyl-1,3,3a,7-
tetraazaindene None cubic C
45 1-(3-Acetamido-
phenyl)-5-mercap-
totetrazole,
~odium salt None octahedral C
46 5-Carboxy-6-hydroxy-
4-methyl-2-methyl-
thio--1,3,3a,7-
tetraazaindene None octahedral C
47 5-Carboxy-4-hy-
droxy-6-methyl-
2-methylthio-
1,3,3a,7-
tetraazaindene None cubic A
35 48 -Thiocaprolactam None cubic (1) A
~2 8~7
-50-
T A B L E II (continued)
{hQQ} Ho~t
Growth Modifier Surfsces Grains Method
49 4-Hydroxy-2-methyl-
thio-1,3,3a,7-
tetraszaindene None cubic A
50 4-Hydroxy-2,6-di-
methyl-1,3,3a,7- octahedral
tetraazsindene None ~4) A
10 51 Pyridine-2-thiol None octahedral
(8) A
52 4-Hydroxy-6-methyl-
1,2,3a,7-tetrs- octahedral
azaindene None (4) A
15 53 7-Ethoxycarbonyl-
6-methyl-2-meth-
ylthio-4-oxo-
1,3,3a,7-tetra-
azaindene 1311} cubic C
54 1-(4-Nitrophenyl) -5- octahedral
mercaptotetrazole None (1)(2) A
55 4-Hydroxy-1,3,3a,7- octahedral
tetraazaindene None (4) A
56 2-Methyl-5-nitro-lH-
benz:lmidazole {211} octahedral A
57 Benzenethiol None octahedral
(1)(8) A
58 Melamine None cubic C
None octahedral C
3059 1-(3-Nitrophenyl)-5- None cubic C
mercaptotetrazole None octahedral C
60 Pyridine-4-thiol None octahedral
(1) A
61 4-Hydroxy-6-methyl-
3-methylthio-
1,2,3a,7-tetra-
azaindene None cubic A
8~ 7
-51-
T A B L E II (continued3
{hQQ} Host
Growth Modi~ierSurfaces Grains Method
62 4-Methoxy-6-methyl-
1,3,3a,7-tetra-
az~indene None octahedral A
63 4-Amino-6-methyl-
1,3,3a,7-tetr~
azaindene None octahedral A
64 4-Methoxy-6-methyl-
2-methylthio-
1,3,3a,7-tetra-
azaindene None cubic A
65 4-Hydroxy-6-methyl-
1,2,3,3a,7-penta-
azaindene None octahedral A
66 3-Carboxymethyl-
rhodanine None cubic (1) A
67 lH-Benzimidazole None octahedral A
68 4-Nitro-lH-benz-
imidazole None octshedral A
69 3-Ethyl-5-[(3-ethyl-
2-benzoxszolinyli-
dene)ethylidene]-
4-phenyl-2-thioxo-
3-thlazoliniumNone cubic C
iodicle None octahedral C
30 i ll \ =CH-CH= / ~ Ie
/ \N/ \S/ ~S
Et
lX~
-52-
T A B L E II (continued)
{hQQ} Host
Growth Modlfier Sur~aces Grains Method
70 3-Ethyl-5-(4-methyl-
2-thioxo-3-thia-
zolin-5-ylidene- None cubic C
methyl)rhod~nine None oct~hedr~l C
0 Me
Et- ~ S/
71 3-I~opropyl-[~3-
ethyl-2-benzothi~-
zolidinylidene)-
ethylidene]rho-
dsnine None cubic B
o
I~ il ~ =CH-CH=-/ ~ -C
Et
72 3,3'-D:Lethylthia-
cyanine P-tolllene
sulfonate None cubic (5) A
I il ~ -CH=-/ Ij ~1
Et Et pts9
73 3-Ethyl-5-(3-ethyl-
2-benzothi~zolin-
ylidene)rhodanine {211} cubic (5) A
o
S ll
.~ \./ \ / \~-Et
~-/ \N/ \S/ ~S
Et
~ 7
T A B L E II (continued)
{hQQ} Host
Growth ModifierSurfaces Grains Method
74 3-Ethyl-5-(3-ethyl-
2-benzothiazo-
linylidene)-2-
thio-2,4-oxazoli-
dinedione None cubic (5) A
o
11
îf \il/S\.=. / ~ -Et
Et
15 75 5-(3-Ethyl-2-benzo-
thiazollnylidene)--
1,3-diphenyl-2- None cubic C
thiohydantoin None octahedr~l C
o
i~/il/\N/-=-~
Et
25 76 3-Ethyl-5-(3-ethyl-
2-benzoxazollnyl-
idene)rhodanine None cublc (5) A
o
I~ 'D' \.=./ ~ - Et
La~ 7
~54~
T A B L E II (continued)
~hQQ~ Host
Growth Modifier Surfaces Grains Method
77 3-Methyl-4-[~1,3,3-
trimethyl-l(H~-2-
indolylidene)-
ethylidene]-l-
phenyl-2-pyrazo- None cubic C
lin-5-one None octahedral C
Me
Me
78 5-(1,3-Dithiolan-2-
ylidene)-3-ethyl--
rhodanine 1322} cubic (5) A
o
~2 1 \.=~/ ~ Et
79 5-(5-Methyl-3-pro-
pyl-2-thiazolinyl-
idene)-3-propyl-
rhodanine {311} cubic (5) A
o
M~./ \ / \y- CH2-CH2-Me
~ \ S/ ~S
C~H2
C~H2
Me
-55-
T A B L E II (continued)
.
{hQQ} Host
Growth Modifier Surfaces Gr~ins Method
80 3-Carboxymethyl-5-
[(3-ethyl-2-benz-
oxazolinylidene)-
ethylidene]rhoda- None cubic C
nine None octahedral C
o
10 o ii
t~ / \ =cH_cH=~/ Y CH2 C 2
~ / \N/ \S/ ~S
Et
15 81 5-(3-Ethyl-2-benzo-
thi~zolinylidene)-
3-B-sulfoethyl-
rhodanine {211~ cubic (5) A
o
CH2-CH2-S03H
Et
82 5-Anllinomethylene-
3-(2-sulfoethyl)-
rhodanine {311~ cubic (6) A
O
30 HS03-CH2-CH2- ~ \ =CH-
S~ \S
-56-
T A B L E II ~continued)
{h~Q} Host
Growth ModifierSurface~ Grains Method
83 3~ Carboxyethyl)-
5-[(3-ethyl-2-
benzox~zolinyli-
dene3ethylidene]-
rhodanine {311} cubic B
o
0 ll CH-Me
I ll ~ =CH-CH=-\ ~ C02H
Et
5 84 3-(1-Carboxyethyl)-
5-[(3-ethyl-2-ben-
zothiazolinyli-
dene)ethylidene]-
rhodanine None cubic B
0
.~ \./S\ /l! ~ CH-Me
!~ I! ~ =CH CH \ /.~ C02H
Et
3-(3-C~lrboxypropyl)-
5-[(3-ethyl-2-ben--
zoxazol~nylidene)-
ethylidene]rhoda-
nine Yeq cubic B
o
~ ,o l!
T il . =CH-CH=./ Y CH2-CH2-CH2-CO2H
~/\~ \S/~S
Et
~81~27
-57-
T A B L E II (continued)
{hQQ} Host
Growth ModifierSurfaces Gr~ins Method
86 3-(2-Carboxyethyl)-
5-[(3-ethyl-2-ben-
zothiazolinyli-
dene)ethylidene]- None cublc C
rhodanine None octahedr~l C
o
S 11
t~ \./ \ / \~ -CH -CH C0 H
I! ,-=CH-CH=-~ 2 2 2
/ W ~S/ ~S
Et
87 3-Csrboxymekhyl-5-
[(3-methyl-2-thia-
zolidinylidene)-
isopropylidene]-
rhodanine None cubic B
O
~~ H22-1 ~ =CH-C-. \ ~ CHZCO2H
Me
88 3-C~rboxymethyl-5-
[(3-methyl-2-thi-
azolidinylidene)-
ethylidene]rhoda- ~
nine None cubic B
o
S
H2--' \ -CH CH- / ~ CH2C2
H-! - - _.
Me
-58-
T A B L E II (continued)
{hQQ} Host
Growth ModifierSurfaces Grain~ Method
89 3-Carboxymethyl-5-
{[3-(2-carboxy-
ethyl)-2 th~azoli-
dinylidene]ethyl-
idene~rhodanineNone cubic B
o
H2_i ~ =CH-CH=- / ~- CH2C2H
( CH2 ) 2C02H
3-(-Carboxy-
benzyl)-5-[(3-
ethyl-2-benzoxazo-
linylidene)ethyl-
idene]rhodanine None cubic B
O
t 11 =CH-CH=-/ ~-CHC02H
~ / \~ \S/ ~S
I
Et
91 3-(-Carboxyben-
zyl)--5-[(3-methyl-
2-thiazolidinyli-
dene)ethylidene]-
rhodanine None cubic B
O q>
HH2_1 ~ =CH-C=- / ~ CHC02H
Me
. ,
27
-5~ -
T A B L E _ II (continued)
~hQQ} Host
Growth Modifier Surf~ces Grains Method
92 1-Ethyl-4-(1-ethyl-
4-pyridinylidene~-
3-phenyl-2-thio- None cubic C
hydantoin None octahedr~l C
o
o Et--N/ \.=. / \~--Et
\ N/ ~S
93 Anhydro-3-ethyl-9-
methyl-3'-(3-sul-
fobutyl)-thia-
carbocyanlne None cubic C
hydroxide None octahedral C
Me
~ ll +\ -CH=C-CH=./ It t
/ \ ~ \ N/ \.
Et cHH22
CH -S03
Me
94 3-Ethyl-5-[1-(4-sul-
fobutyl)-4-pyri-
dinylidene]rhoda-
nine, piperidine ~one cubic C
~alt None octahedral C
o
3 2 4 N~ _ / \ / -
I + I
H~ ~H
8~ ~7
-60-
T a B L E II (continued)
{hQQ} Host
Growth Modifier Surfaces Grains Method
95 5-(3-Ethyl-2-benzo-
5thiazolinylidene)-
l-methoxycarbonyl-
methyl-3-phenyl- None cubic
2-thiohydantoin None octahedral C
o
10 ~Ss\5~
Et CH2
C=O
OCH3
96 1,1',3,3'-Tetraeth-
ylimidazo(4,5-b)-
quinoxalinocar-
bocyanine ~-tolu-
enesulfonateNone cubic B
Et Et
N \ ~ \ 4
t il i =CH-CH=CH - + ~
25 ~./ \ ~ \ ~ ~ ~N/ \-f
Et pt~Et
97 3-(2-Carboxyethyl)-
5-(1-ethyl~4-
pyridinylidene)- cubic
rhodanine ~311} (1)(2) A
o
Et- ~ CH2-cH2co2H
-61-
T A B L E II (continued)
{hQ~] Host
Growth ModifierSurfaces Grains Method
98 3-Carboxymethyl-5-
{[3-(3-sulfopro-
pyl)-2-thiazoli-
dinylidene]ethyl-
idene}rhoda-
nine, sodium salt None cubic (1) A
o
Il
H2-l\ ~ =CH-CH=./ ~ _CH2-C02H
(CH2)3Soe Na+
99 3--(1-Carboxyethyl)-
5-{[3-(3-s~lfo-
propyl)-2-thiazol-
idinylidene]ethyl-
idene~rhoda-
nine, ~odium salt None cubic B
1l CH3
H2_i ~ =CH-CH=.~ ; ~- CH-co2H
e
(CH2)3S03 Na
-62-
T A B L E II (continued)
{hQQ} Host
Growth ModifierSurfaces Grains Method
100 3-(3-C~rboxypropyl)-
5-{[3-(3- ulfo-
propyl)-2-thiazol-
idinylidene}ethyl-
idene}rhoda-
nine, sodium selt None cubic l7) A
o
Il
H2_i\ ~ =CH-CH= \ ; ~ CH2)3C2H
(CH2)3S0~ Na
101 3-(2-Carboxyethyl)-
5-~[3-(3-~ulfo--
propyl)-2-thi~zol-
idinylidene~ethyl-
idene}rhoda- None cubic C
nine, sodium salt None octahedral C
o
s l!
H2-i =CH-CH=./ ~- CH2-CH2C02H
2 \N/ \ S/ ~S
(CH2)31503 Na
~281~7
-63-
T A B L E II (continued~
{hQQ} Host
Growth ModifierSurfaces Grains Method
102 3-Carboxymethyl-5-
(2-pyrrolino-1-
cyclopenten-l-yl-
methylene)rhoda-
nine, sodium salt {211} octahedral A
302C--CH2 1I N/
~ \ =CH- I~ \
15 103 3-Ethyl-5-(3-methyl-
2-thiazolidinyli-
dene)rhodanine {2111 cubic (5) A
o
H2-j/ \ _./ \~- Et
H - /
Me
104 5-(4-Sulfophenyl-
azo)--2-thiobarbi-
turic acid, None cubic C
sodium salt None octahedral C
o
o3S--f ~.-N=N-./ \yH
N + ~ S
a H
~X81~27
-64-
T A B L E II ~continued)
{hQQ} Host
Growth Modifler Surfaces_ Gra~ns Method
105 3-Carboxymethyl-5-
(2,6-dimethyl-
4(H)-pyran-4-yli-
dene)rhodanine {211} cubic (5) A
o
10 ~< \, = . / \~1--CH2 C02H
106 Anhydro-1,3'-bis(3-
~ulfopropyl)naph-
tho[l,2-d]-thia-
zolothiacyanine
hydroxide, tri-
ethylamine salt None cubic (5) A
(CH2)3
S03~ S03e HNEt3
107 3-Ethyl-5-[3-(3-sul-
fopropyl)-2-benzo-
thiazolinylidene]-
rhodanine, trieth-
ylemine salt {211} cubic (5) A
0
~ /S\ / ~ _ Et
~-/ \N/ \S/ ~S
(CH2)3
SOe HNEt3
-65-
T A B L E II (continued)
~hQQ} Host
Growth Modifi.er Surf~ces Gr~ins Method
108 3-Ethyl-5-[3-(3-sul-
fopropyl)-2-benz-
oxazolinylidene]-
rhodanlne, potss- None cubic C
slum salt None octahedral C
o
0 11
T~ \tl/ \.=./ \9J-- Et
~ / ~ \S/ ~S
(CH2)3S33 K+
(l) 3 mmoles of growth modifier/Ag mole of
host gr~i.n emulsion was employed
(2) a pBr of 1.6 was employed
(3) 9 mmoles of erowth modifier/Ag mole of
ho~t g~fiin emulsi.on was employed, added
in two portions
(4) 50C was emp].oyed ir.stead of 60~C
(5) 2 mmoles of growth modifier/Ag mole of
host eraln emulsion was employed
(6) l.5 mmole~ of growth modifier/Ag mole
of host grain emulsion was employed
(/) 4 mmol.es of growth modifier/A~ mole of
host ~rstn emulsion was employed
(8) a p~r of 2.3 w~s employed
ComP~rstive Example 18
The purpose of thi~ comparative example is
to report, the result of sdding 6-nitrobenzimid~zole
to a re~ction vessel prior to the precipit~tion of
~i.lver bromide, as su~eested by Wulff et al U.S.
Patent l,696,830.
A rescti.on vessel. equipped with a 3tirr~r
waa charged wlth 0,75 g of delonized bone ~elatin
made up to 50 ~ wi.th water. 6-Nttrobenzimid~zole,
z~
-66-
16.2 mg (0.3 wei~ht % hased on the Ag used),
di3solved in lmL of methanol, wa~ sdded, followed by
0.055 mole of KBr. At 70~C 0.05 mole of a 2M
sol.ution o~ A~NO3 wa~ added at ~ uniform rate over
5 8 period of 25 mi.n. The grai.ns formed were relative-
ly thi.ck tabtets 3howing {111} crystal fsces.
There was no indicati.on of the novel icositetrahedral
crystsl faces of the invention.
Comparative Example 19
The purpo~e of this comparative example i5
to report the result of employing 4-hydroxy-6-methyl-
1,3,3a,7-tetr~azai.ndene, sodium salt during grain
precipitati.on, as suggested by Smith Particle Growth
and SusPension, clted above.
To 100 mL of a 3% bone gelatin solution were
added sl.mul.taneousl.y 10 mL of 1.96 M AgNO3 and lOmL
of 1..96 M KBr at 50DC with stirring over a period of
about 20 sec. The A~r di.spersion was aged for 1 min
at 50C, then dl1.uted to 500 mL. The dispersion was
ad~usted to p~r 3 with KBr.
_amples 19a and l9b.
To 80mL of lX10 M KBr containing 0.4
mmole/Q of 4-hydroxy-6-methyl-1,3,3a,7-tetraaza-
~.ndene, sodi.um salt and 0.6 mmole/Q of l-dodecyl-
qui.nol.ini.um bromide was ~dded 20 mL of the ~bovedtsper~ion, whi.ch was then stirred at 23~C. Samples
were removed ~fter 15 min (Sample l9a) and 60 min
(Sample l9b).
SamPles l9c and l9d
SQmples 19c and l9d were prepared similarly
as Samples 19a and 19b, respectively, except that 0.8
mmole/Q of 4-hydroxy-6-methyl-1,3,3a,7-tetrQazain-
dene and 0.6 mmol.e/Q of l-dodecylquinolinium
bromide were used.
~xaml.nation of the grains of each of thP
samples revealed rounded cublc grains. No icosi-
tetrsheArsl. crysta1. faces were observed.
lX~ 27
-67-
Exam2le 20
Emulsi.on ~xample 20 illu~trates the
preparation of ~ ruffled tsbul.ar grsin silver bromide
emulsion us1.ng ~9 a growth modlfler Compound 81,
5-~3-ethyl-2-benzothi.azolinylidene)-3-~-sulfo-
ethyl rhodanl.ne, which is known to be useful as a
blue spectral sensitizing dye.
To a reactlon vessel suppl~ed with a stirrer
was added 0.04 mole of a thln and high aspect ratio
tsbular grain AB~r emul.~ion of mean grain 3ize 5.6
~m, thicknes~ 0.10 ~m containin~ about 20 g/Ag
moJ.e gelati.n. Water was ~dded to make the total
we.i.ght 40 g. To the emul.sion at 40~C was sdded 4
mill.i.mole/i.nl.tial. Ae mole of Compound 81 dissolved in
7mL of N,N-dimethy1.formam5.de, 3mL water, and 2 drops
of triethy~.amlne. The emulsion was then held for 15
min at 40C. The pH was sd~usted to 6.0 at 40C.
The temperature W8S raised to 60C, snd the pAg
ad~u~ted to 8.5 at 60C with KBr and msintained at
that value during the preci.pitation. A 2.OM solution
of AgN03 was introduced at a constant rste over a
pe~lod of 2.0 min whi.le a ~M soluti.on of KBr was &dded
es needed to hold the pA~ constant. A total of 0.02
mole Ag wss added.
An electron ml.crograph of the resulting
emulsion grain~ i.s shown in F.tgure 28. The grsin
faces were uni.forml.y covered with closely arranged,
sharp, small pyrami.dal ruffles. This was consi~tent
w.l.th the [2.11~ icositetrahedral cry~tal faces
expected from i.nvesti.~ation of the same growth
modi.fier empl.oyin~ a nontabular host grain emulsion.
Example 21
Example 21. illustrates the preparation of
ruffled tabulsr ~rain silver bromoiodide emulsions
us1.n~ Compound 81 a~ the growth modifier. Example
21A i.s a control showing that no ruffles are formed
i.f t;he growth modi.fier is added following, rather
-6B-
than preceding, the silYer halide precipitat~on on
the host emulslon.
To a reaction ves~el ~upplied with 8 gtirrer
WAS added 0.05 mole of a thin and high aspect ratio
tabul&r grain sllver bromoiodide emul~ion (6 mole
I) of mean 8rain size 5.3 ~m, thickness 0.07 ~m,
and containi.ng about 40 g/Ag mole gelatin. Water was
added to make the total weight 50 g. To the emulsion
at 40C prepared accordinp, to the lnvention was added
Compound 81 d5.ssolved i.n 12mL of N,N'-dimethyl-
formamlde-water-triethylQmJ.ne mixture similar to that
de~cri.bed i.n the previous example. In the control
the introducti.on of Compound 81 was delayed until
after preci.pitation. The emulsion was then held for
15 mtn. at 40~C. The pH was ad~usted to 6.0 at
40C. The temperature was raised to 60C, and the
pAg ad~usted to 8.5 at 60~C with KBr and maintained
at that vsl.ue during the precipitation. A 2.OM
so~.ution of AF~N03 was i.ntroduced at a constant rste
over a peri.od of 74 mi.n. while a ~olution that was
1.88M J.n KBr and 0.12M i.n KI was added a9 needed to
hold the pA~ constant. A total of 0.015 mole Ag W8S
added. The deta5.1s of the three experiments are
shown in Table III.
TABLE III
Exam~l.e 21 PreclPitatlons
Cpd. 81
Figure mmole/
Example No Ap~ mole Comments
21A 29A 3.0 Control - Cpd. 81 added
after precipitation
21.B 29B 3.0 Invention
21C 29C 4.5 Invention
Fi.gures 29A, B, and C show electron
mJ.crogr~phs of the resultin~ grAins. In Example 21A,
aAdlti.on of the growth modi.fier after the precipita-
ti.on resulted .Ln no growth of ruffle~ on the host
-69-
emulsion grslns. Ex~mple 21B, with the same amount
of growth modi.fi.er added prior to the precipitstion,
produced uniform, closely ~rrsnged, smsll ruffles.
Exsmple 21C, with a hi.gher level of growth modifier,
produced a si.mllsr re~ul.t, but with slightly better
defined ruffles (pyrsmids).
Measurement was msde of the interf~cisl
snele o 8 ruffle on an electron micrograph of
ExPmple 6C l.n order to determine the crystsllogr~phic
form. The ~ngle between the f~ce vectors w~s found
to be 35. The theoreticsl. sngle between [211]
vectorq i.s 33.6. The form wss therefore {211}
I.cosltetrshedral. Thi.s is consistent with other
observsti.ons of {211~ icositetrshedrs being
formed st~rtl.ng wlth nontsbul~r host grsins ~nd
employi.ng Compound 81 as a growth modifier.
Example 22
Example 22 sgai.n illustrstes the preparation
of ruffled tabul.sr grsin silver bromoiodide emulsions
using Compound 81 (Exsmpl.e 20) a5 the growth
mod:l.fler, but shows the dependence of the result on
the level of growth modifier added.
The host emulqion (0.05 mole for esch
expe~Lment) snd the precipltsti.on conditions were 8S
descrlbed ln Example 21.. The detsils oE the
experiments sre shown in Tsble IV.
TABLE IV
ExamPle 22 PreciPit~tions
Flgure Cpd. 81
30Exame~e No mmolelA~ mole
22A 30A 0
22~ 30B 0.75
.2C 30C 1.5
22D 30D 3.0
Figures 30A, B, C, and D are electron
microgrsphs of the resultlng emulsion grains.
Exsmple 22A, wlthout growth modifier, ~nd 22B, with
-70-
0.75 ml.llimol.e/Ag mole, showed no ruffles. At 1.5
mil.limole, relati.vely large truncated pyrsm~ds
sppeared, ~s ~hown in Figure 30C. At 3.0 millimoles
Example 22D producPd uni.form, closely srranged, small
ruffJ.es. The pyramidsl cry~tal fsce3 were consistent
wlth the ~211} cryst~l faces expected from u~ing
Compound 81 as ~ growth modifi.er in the previou3
examples.
ExsmPle 23
Example 23 .I.llustrates the preparation of
ruffled cubi.c sllver bromide grsln~ using Compound
36, 2-merc~pto.i.mi.dszole, ss e growth modifier.
Cont.Lnued erowth results I.n icositetrahedr~l gr~ins.
To a reaction vessel supplied with a stirrer
was sdded 0.05 mole of 8 cubic regular gr~in silver
bromide emul.sion of mesn grsin flize 0.8~m,
contsining about 10 ~/Ag mole gelatin. Water was
sdded to make the total weight 50 g. To the emulsion
st 40C wss sdded :3.0 mil.li.moletAg mole of Compound
36 ~J.ssolved in 3mL methanol. The emulsion was then
hel.d for 15 m~n at 40C. The pH was sd~usted to 6.0
st 40~C. The tempersture was rsised to 60C, snd the
pAg ~dJusted to R.5 st 60C with KBr snd maintsined
st thst value durin~ the precipit~tion. A 2.5M
~olution of AgNO3 wss ~dded ~t a constsnt rate over
a per:lod of ~5 min whi.le ~ ~.SM solution of KBr wss
added ss needed to hold ~he pAg constAnt~ A totsl of
0.0125 mol.e Ae, WQS sdded to form Ex~mple 23A. For
Ex~mple 23~ the preci.pltatlon wss continued for a
total of 1~5 ml.n, using a total of 0.0875 mole Ag.
An sddltlon~l 3 mi.].l.imole/i.nitial Ag mole of Compound
36 wss ~dded sfter lO0 min of precipitation time.
Fl~ures 31A snd 31~ ~re electron microgr~phs
of the resulting emulslon grsins produced by Examples
23A and 23~, respecti.vely. Figure 31A shows 8
p~ttern of growths covering the crystal fsces.
Fi.gure 31~ .illustrstes the formstion of ~533}
1~ 8~ 7
-71-
ico3itetr~hedral Rra.ins with continued precipltation.
Example 24
Thi.~ example i.llustr~te~ the modificstion of
a growth modtfter ad~orbed to lcositetr~hedral grain
5 gurfaces~
The emul~lon empl.oyed was a ~ilver bromo-
iodlde (6 mole percent iodi.de) emulsion containing
.J.cositetrahedral grains, the emulsion being prepared
by a procedure ~imi.1ar to that of Example 9, except
t,hat the host emul.slon was a 0.7~m silver bromo-
lod:ide (6 mole percent, i.odlde) ootahedral grain
emulslon and the over~rowth ~hase consisted of silver
hromolodi.de (6 mole percent iodide) obtained by
havinp, an app~opriate amount of NaI in the NaBr salt
sol.utlon. The amount of overerowth precipitated was
3.13 times the number of moles of host emulsion used.
The resultlnR icositetrahedrfll 8rain
emulsion had 8 pink color due to the adsorption of
Compound VIII, a dye employed as the growth modifier,
ont,o the gra.i.n's surfaces. The addition of bromine
water resulted i.n the complete disappearance of the
pink color, lndi.cating destruction of the dye,
leaving a yellow color havlng a slight brownish
tlnt. The yellow color i9 that expected for AgIBr
and the brownish tlnt ts attributed to the reaction
products formed i.n destroylng Compound VIII.
Example_25
Thi.s examp~.e illustrates the preparation of
an i.cosltetrahedrst silver bromide emulsion having
the Mlller lndex {211), beglnning wlth an
octahedral core emulslon, and using Compound 102 from
Tahle II ag a erowth modl.fi.er. This example further
lllustrfltes that the growth modifier can be rendered
tnactive hy treatment wtth bromtne water, and a new
spectral sensttizing dye can then be used.
The emulsl.on for this example W8~ prepared
a9 described for Example 1, except for the following
1~81~Z~
changes: The erowth modifler W89 2eO millimol2~Ag
mole of Compound ].0~, di~solved in 8 mL methanol, 5
drops triethylami.ne and 8 ml. distilled water. The
starting emulsLon was 0.4 mole of a O.7 ~m ARBr
oct~hedrsl emul.si.on containing 16g of gelatin and a
total volume of 400g. The AgN03 solution WRS ~dded
at a constant rate for 140 min, resulting in 0.70
moles of addit.Lonal AgBr being precipitated. The
NaBr sol.ution was twlce as concentrated (5.0M) as the
AgN03 solutlon and was added as needed to hold the
pAg constant.
Carbon repl.lca electron micrographs showed
that well formed {~].1} i.cosi.tetrahedra resulted.
The resultinR emuls:lon W8Q divided in half.
Portlon A. Thls hslf was gently centrifuged
and the solld portion resuspended in 300g of 3.7
bone gelRtin solution.
Porti.on B. To this half at 40C, bromine
wster was slowl.y added with good stirring until the
pink color caused by the adsorbed growth modifier had
di.sappeared as determi.ned by dissolving small samples
~nd exami.nl.ng them in white llght. Note: 42g of
broml.ne water had been added in 13 min. After the
pink color had di~appeared, an additional lOg of
bromine water wss slowly sdded. The resulting
emu1.slon was gentl.y centrlfuged and the solid AgBr
phase WflS resuspended in 300g of 3.7% bone gelatin
solution.
Porti.ons A and B were further trested as
I.lsted below and costed on acet~te ~upport at 1.08 g
Ag/m , 4~31R hone Rel.sti.n/m , and 0.81 g/m of
a d:LAper~lon o~ the coupler 2 benzamido-5-[2-(4-
butane~ulfonyl.am~dophenoxy)tetradecanamido]-4-
chlorophenol, 0.1'~ saponi.n/m as ~preading agent,
and 1.8mg hls(vinylQulfonyl.methyl)ether/g gelstin as
hardener.
~ ~ 81~7
-73-
Emulsion
~. Portion A
2 Port.i.on A + 0.26 mmole/mole Dye A
3 Portion A heated 15 min at 70C with 1.2
mg/mole sodt.um thlosulfate and 0.4 mglmole
potassium chloroaurate
4 Portion B + 0.26 mmole/mole Dye A
Portion ~ heated 15 min at 70~C with 3,6
mg/mole so~ium thiosulfate and 1.2 mg~mole
potassium chloroaurste
6 Portton B heated 15 min at 70C with 3,6
mg/mole sodium th~.osulfste and 1.2 mg/mole
potassium chl.oroaurate + 0.26 mmole/mole
Dye A
Dye A ls fl red spectral sensitt.zing dye having the
formula:
~ -\ /s\ /s~
!~ U ~ --C~--cl--CH~,i!~ i!
(CH2)3S03 (CH2)3S03
Anhydro-5,5'-dichloro-9-ethyl-3,3'-di(3-sulfo-
propyL)thiacar~ocyan3.ne hydroxide, sodium salt
These coati.np,s were exposed to a regulated
light source whl.ch progressively increased in
wavel.enet,h i.n one dlrection and progressively
i.ncreased i.n denslty i.n a second direction normsl to
t,he fl.rst~ The coati.ngs were then processed in the
Kodak C-41~ Color Negative Process (with develop-
ment for 3 mi.n 15 9 at 38C) which formed a cyant.maRe showing the s~ectral response of each coating.
Thls l.mage was scanned by a densitometer, and
corrected for var:t.sble lamp energy to produce the
t,races of constant lma~,e density shown in Figures 32A
and 32B. In Flgure 32A the curves 1, 2, and 4
lndt.cste results for the correspondingly numbered
coatln~s, whi.ch were not chemically sensitized,
~..X81~7
-74-
Sim.Llarly, ln F~gure 32~ the curves 3, 5, and 6
i.ndl.cate results for the correspondingly numbered
coatings, where were chemically sensitized.
By comp&ring curves 1 and 2 in Figure 32A it
5 can be seen that the addLtion of red sensitizing dye
A 3.ncreased the sensitivity of the emulsion somewhat,
but did not functi.on to shLft the spectral response
of the emulsi.on. This is because growth modifier
Compound 102, whlch i9 itself a green ~pectral
sens3.tlzlng dye, WQ~ already sdsorbed to the
icositetrahedrRl grAin surfaces. Curve 4 shows the
spectral. re~ponse obtained when the green spectrsl
sensLtizlng dye, Compound 102, is destroyed as 8 dye
prlor to addl.tlon of Dye A. As can be seen from
curve 4, the emuls3.on exhibits no measursble
senslt:lvlty ~.n the 470 to 510 nm region of the
spectrum, but exhi.hLts a marked increase in spectral
sensl.tJ.vi.:lty heyond 650 nm. The curves demonstrate
that the spectral. sen~lti.vity lmparted by the growth
modlf~er can be destroyed to 8110w spectral senqiti-
zatlon of the icositetrahedral emulsions according to
the inventlon to a differing portlon of the visible
spectrum, if desired.
Looki.ne at Figure 32B, it can be seen from
curve 3 that the chemically sensitized icositetra-
hedral. emuls3.on exhi.bi.ts measurable ~ensitivity out
to about 650 nm aq i.nLti.ally prepared. Sensitivlty
ln the 8reen portion of the spectrum is attributable
to the green senslti.zation provided by the growth
modi.fier, Compound 102. Curve 5 shows the native
sensltJ.v:lty remaLni.ng when the spectral sensitizatiLon
provided by Compound 102 is destroyed by treating the
emulsion wJ.th bromine water. Curve 6 shows the
response obtai.ned when the red spectral sensitizing
dye, Dye A, i.s thereafter added to the emulsion.
Cumulati.vely Flgure 32A and 32~ show the spectral
sensiti.zat.l.on et`fect~ to be achievable independently
of chemJ.cal sens3.tlzat3.on of the emulsions.
~ 8~ 7
-75-
ExamPle 26
Thls example i.l].ustrates the selective site
ep.l.taxlsl depos:Ltlon of 8 silveF salt onto icosi-
tetrshedral. gralns of an emulsion sstisfying the
requirement~ of thi~ invention.
To a ~eaction vessel supplied with a stirrer
was added 0.~ mole of & 0.7~m sllver bromoiodide (6
mole percent i.odide) octahedral emulsion containing
~8g bone gelst~.n/Ag mole. Distilled water W8~
sdded so that the contentR of the kettle weighed
400g. The emulsi.on wsR heated to 40C, and 6.0
mmol.es/Ag mole of 2-methyl-5-nitro-lH-benzimidazole
dLssolved in 25ml of methanol was added. The mixture
W8S held for 15 mln st 40~C. The pH was sd~usted to
lS 6.0 st 60C snd the pAg sd~usted to 8.5 st 60C and
mslntalned st these vslueR durtng the precipitation.
A 2.5M solutJ.on of A~NO3 was added &t a constant
rate over a psrl.od of 200 mLn consuming Q.5 moles of
Ag. Concurrently, a ~oluti.on of 4.95M in NsBr snd
0.3M ln NsI was added st e rste necessary to msintsin
a constant pA~ of 8.5 st 60C. The resulting
emul.slon wss centri.fuged and the solid silver halide
phsse wss resuspended Ln 200ml of 3% bone ~elatin
solution. C~rbon replic& electron microgrsphs showed
this emulsion to consist of well formed ico~i-
tetrshedrs.
Two epl.tsxlal emulsions were prepared. One
w~ made ln the presence of the epitaxial qite
director, Compound I, the other wss not.
i ~ 81~ 7
-76-
ompound I
~cH-c-c~l-. ~ ll ll
CH~C~l2CH-CH3 CH2CH2CH-CH3
S03Na S03
Anhydro-9-ethyl-5,5'-diphenyl-3,3'-
dJ.(3-sulfobutyl)oxacarbocyanine
hydroxlde, monosodium salt
To p~epare Emu1Aion A, to a reaction ve~el
supplied with 8 st.l.rrer was added 0.05 mole of the
a~ove irosLtetrahedrsl host emulsion. Distilled
water was added to mske a totsl contents weight of
SOg. The contents were heated to 40~C &nd 0.92 mmole
of NaCl W8s sdded. An 0.50M solution of AgN03 and
R 0. 52M soluti.on of NsCl was then introduced with a
const~nt ~l1ver Rddition rate over a period of 10
min, con~umine 2.5 mmol.e of sLlver. During the
precLpltation, the pAg was hel.d con~tsnt at 7.5 and
the temperature held con~tant at 40C.
To prepare Emulsi.on B, a qimilar procedure
was loll.owed 8S ln the precipitat3.on of Emul~ion A,
but wLth the followln~, excepti.ons: Before the start
of the AgC:l preclpi.tQtlon, 0.64 mmole of Compound I
(&9 ~hown a~ove)/host A~ mole .l.n 2 ml methsnol was
Qdded.
Both Emul~i.on A and Emulsion B showed
discrete epLtaxial deposits. In the ca~e of Emulsion
B, wh3.ch was preci.p3.t~ted 3.n the presence of the site
d.l.rector, the cubic {100~ crystal fsces on the
ep3.taxy were quite dl.~tinct. Thls exsmple demon-
strates that no addLtional site director, ~uch as
Compound I, i.s es~enti.al to achieving selective site
ep3.taxy, hut ~n adsorbed site director can be
Advantaeeous in achi.ev.Lng better definition of
cry~tal faces.
~ 7
ExamPle 27
This example i.llustrates 3elected site
ep~taxy on ~n i.cositetrahedrsl host emul~lon.
The host emulsion for ~,hi~ example wa.~ that
emp~.oyed i`or Example 25. To a reaction vessel
supplled with a st.l.rrer was added 0~05 mole of the
host emulslon, 0.52 mmole l,l'-diethyl-2,2'-cyanine
p-toluenesulfonate i.n 2ml of methanol and distilled
water to make a totsl wei.ght of contents of 50g, The
contents were heated to 40C and 0.92 mmole of NaCl
was added. A O.~OM so].ut1.on of AgNo3 and a 0.52M
soluti.on of NaCl. were then introduced with a constant
siJ.ver addi.ti.on rate over a period of lO min
consumlng 2,5 mmoles of sil.ver. During the precipi-
tation, the pAg wa~ held constant at 7.5, and thetempersture held constant at 40~C.
A 20,000X carbon replica electron micrograph
of the resulti.ng emu].sion which has discrete
epitaxl~l. growths alonQ the edges ~oining coigns
formed by the 5.ntersections of four crystal faces,
but no epitaxy along the edBes intersecting st coigns
formed by t,he intersecti.ons of three crystal faces.
Thus, there were three well defined, mutually
perpendicular rlnes of epltaxy around each icosi-
tetr~hedral grain.
The .Invention has heen described in detailwith partlcular reference to preferred embodiments
thereof, but i.t wll.l be understood th~t variations
and modi.flcations can be effected within the splrit
and scope of the invention.
