Note: Descriptions are shown in the official language in which they were submitted.
1~9~
REVERSAL PHOTOGRAPHIC ELEMENTS
CONTAINING TABULAR GRAIN EMULSIONS
Field of ~he Invention
This invention relates to improved photo-
graphic elements adapted for producing reversalimages. More specifically3 thls invemtion relates to
reversal silver halide photographic elementæ
containing in at least one emulsion layer tabular
haloiodide grains.
Back~round _ the Invention
The term "silver haloiodide" i~ employed in
its ~rt recognized usage to designate silver halide
grains containing s~lver ions in combination with
iodide ions and at least one of chloride and bromlde
ions. The term "reversal photographic elemen~"
designates a photogrsphic element which produces a
photographic image for v~ewing by being imagewise
exposed and developed to produce a nega~ive of the
image to be viewed, followed by uniform exposure
and/or fogging of residual silver halide and process-
ing to produce a second, viewable image. Color
slides, such as those produ~ed from Kodachrome- and
Ektachrome- films, constitute a popular example of
reversal photographic elements.. In the overwhel~ing .
25 -majority of applications.the fir6t image i8 negative
and the second image is positive. Groet U.S. P~tent
4,082,553 illustrates a conventional reversal
p~otographic element containing silver haloiodide
grains modified by the incorporation of a small
proportion of fogged silver halide grains. Hayashi
et al German OLS 3,402,840 is similar to Groet, bu~
describes the imaging silver halide grains in terms
of those larger than and smaller th~n 0.3 micrometer
and additionally requlres in additlon to the fogged
silver halide grain6 or their metal or metal ~ulfide
equivalent an organlc compound c~pable of forming
silver salt of low solubility.
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Hlgh aspect ratio tabular grain silver
haloiodide emulsions have been recognized to provide
a variety of photographic advantages, such as
improvements ln speed-granularity relationships,
increased image sharpness, and reduced blue speed of
minus blue recording e~ulsion ~ayers. High aspect
ratio tabular grain silver haloiodide emulsions in
reversal photographic elements are illustrated by
Research Disclosure Vol. 225, January 1983, Item
22534; Wilgus et al U.S. Patent 4,434,226; Kofron et
al U.S. Patent 4,439,520; Solberg et al U.S. Patent
4,43~,048; Maskasky U.S. Patent 4,400,463; and
Maskasky U.S. Patent 4,435,501. Research Disclosure
is published by Kenneth Mason Publications, Ltd., The
Old Harbourmasterlg, 8 North Street, Emsworth,
~ampshire P010 7DD, England.
Brief Description of ~Q Drawin~
This invention can be better appreciated by
reference to the following detailed descrlption
considered in conjunction with the drawings, in which
Figure 1 is a schematic diagram intended to
compare qualitatitively the reversal characteristic
curve 2 o~ a reversal photographic element according
to this invention with the rever~al characteristic
curve 1 of a reversal photographic element differing
only in lacking a second grain population;
Figures 2 through 10 present and compare
reversal characteristic curves of elements exempli~y-
ing this invention, identified by the prefix E before
the element number, and comparative elements,
identified by the prefix C before the element number.
Sum~larv of the Invention
In one aspect this invention is directed to
a photographic element capable of forming a reversal
image comprising a support and, coated on the
support, at least one image recording emulsion layer
r~ ~?
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5 ~3 ~3 L~L 5
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comprised of a dispersing medium and a blend of
radiation sensitive tabular silver halolodide grainæ
having a thickness of less than 0.5 ~m, a diameter
of at least 0.6 ~m, and an average aspect ratio of
greatex than 8:1 accounting for at least 35 percent
of the total grain projected area of said emulsion
layer and relatively fine grains present in a
concentration sufficient to improve re!versal photo-
graphic imaging consisting essentially of a sllver
salt more soluble than silver iodide.
It has been discovered that the addition of
relatively fine grains consisting essentially of a
silver salt more soluble than silver iodide to an
emulsion layer containing tabular silver haloiodide
grains can produce a combination of advantages in
reversal imaging. The reversal threshold speed of
the reversal photographic elements can be increased.
At the same time, reduced toe region density in the
reversal image as well as increases in maximum
den~ity and contrast are observed,
To permit the advantages o~ the present
invention to be visualized more easily, the relative
reversal imaging performance of a photographic
element according to the present invention and a
conventional reversal photographic element differing
solely by the absence of the relatively fine grains
consisting essentially of a silver salt more soluble
than silver iodide is illustrated ~chematically in
Figure 1. Curve 1 is the rever~al characteristic
curve produced by an emulsion layer of a conventional
reversal photographic element wherein radiation
sensitive tabular silver haloiodide grains are
pre~ent~ but the relatively fine grains are not
present. Curve 2 illustrates the reversal charac-
teristic curve produced by the same emulsion layerdiffering only by the incluaion of the relatively
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fine grains. It is to be understood that exposure
and processing producing both curves are identlcal.
In the toe region 2a of the characteristic curve 2 it
can be seen that density is lower than in the
corresponding toe region la of the characteristic
curve 1. Thus the inventive reversal photographic
element produces images having hrighter highlights.
Comparing the mid-portions lb and 2b of the charac-
teristic curves, it can be seen that the character-
istic curve of the photographic element according tothe invention exhibits significantly higher
contrast. Comparing the shoulder portions lc and 2c
of the characteristic curves, it can be ~een that the
shoulder portion 2c o~ the characteristic curve of
the reversal photographic element sat;sfying this
invention is of much higher density. In comparing
the shoulder portions lc and 2c of the characteristic
curves it can be seen that curve 2 is already
declining from maximum density at minimum exposure
level shown while the threshold decline from maximum
density of the curve 1 occurs well within the density
scale. Thus, it can be seen that the reversal
threshold speed exhibited by curve 2 exceeds that o~
curve 1, where reversal threshold speed is defined as
the exposure Ievel corresponding to the thre~hold
(first detectable) decline from maximum density of
the reversal characteristic curve. Shifting from the
language o~ the photographic scientist to that of the
ultimate user, the photographer, the present inven-
tion adds speed~and "snap" to reversal photographicelements employing radiation sensitive tabular grain
emulsions.
The inventive character of the reversal
photographic elements herein disclosed is underscored
when it is appreciated that highly analogous reversal
photographic elements differing in one or more
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essential features of this invention do not exhibit
even qualitatively predictable similarities in
performance when the relatively fine grain silver
salts are introduced into the reversal photographic
elements. Specifically, when the relatively fine
grains of silver salt are placed in layers adjacent
to rather than in the radiation sensitive tabular
grain emulsion layer, the result is a ~ in maximum
density, a loss of contrast, and an increase in toe
region and minimum densities. If a conventional
nontabular silver haloiodide emulsion is substituted
for the tabular grain emulsion layer, the result is
marked reversal desensitization, which necessarily
increases toe region density at comparable exposure
levels. If relatively fine grain silver iodide is
substituted for relatively fine grains exhibiting a
higher level of solubility, no enhancement of the
characteristic curve shape is observed. Still
~urther, advantageous modifications of reversal
characteristic curve shape have been realized only
when the radiation sensitive tabular grains are
silver haloiodide grains as opposed to tabular silver
halide grains lacking iodide as a constituent.
Description of Preferred Embodiments
This invention relates to an improvement in
silver halide photographic elements useful in
reversal imaging. The photographic elements are
comprised of a support and one or more image record-
ing silver halide emulsion layers coated on the
support. At least one of the image recording
emulsion layers contains a dispersing medium and
radiation sensitive tabular silver haloiodide grains
blended with relatively fine grains consisting
essentially of a silver salt more soluble than silver
iodide.
Tabular grains are herein defined as those
having two substantially parallel crystal faces, each
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o which is cle~rly larger than any other single
erystal face of the grain. The tabular grains
employed in the blended grain emulsion layers forming
one or more layers of the reversal photographic
elements of this invention are chosen so that the
tabular grains having a thickness of less ~han 0.5
um and 8 diameter of at least 0.6 ~I have an
average aspect ratio of 8reater than 8:1 and account
for at least 35 percent of the to~al grain projected
area of the blended grain emulsion layer in which
they are present.
A convenient ~pproach for preparing blended
grain emulsion layers satisfying the requirements of
this invention is to blend with the relatively fine
second grain population a radiation sensitive high
aspect ratio tabular grain emulsion. The term "high
aspect ratio tabular grain emulsion" is herein
de~ined as requiring that the tabular silver halide
grains having a thickness of less thsn 0.3 ~m ~nd a
diameter of at least 0.6 ~ have an average ~spect
ratio of greater than B:l and account for a~ least 50
percent of the total proje~ted area of the grain~
present in the emulsion. The term is thus defined in
conformity with the usage of thls term in the patent~
25 relating to tabular grain emulsions cited above.
In general tabul~r grains are preferred
having 3 thickness of less than 0.3 ~m. Where the
emulsion layer is intended to record blue light as
opposed to green or red light, it ~s advantageous to
increase the thickness criter~on of the tabular
grains to less ~han 0.5 ~m, instead of less than
O.3 ~m. Such an increase in tabular grain thick-
ness is also contemplated for applications in which
the reversal image is to be viewed w~thout enlarge-
35 ment or where granularity is of little importance,al~hough ~hese lat~er applic~tions are relatively
~ ~ S ~ 8~
rare in reversal imaging, reversel images being most
co~monly viewed by projection. Tabul~r grain
emulsions wherein the tabular grairs have a thickness
of less than 0.5 ~ intended for recording blue
S light are disclosed by Kofron et al U.S. Patent
4,439,520, cited above.
While the tabular grains satisfying ~he O . 3
~m thickness and 0.6 ~m diameter criteria account
for at least 50 percent o the total ?rojected area
of the grains in high aspect ratio tabular grain
emulsions, it is appreci~ted that in blending &
second grain population ~he tabular grain percentage
of the tot~l grein projected area is decreased. The
tabular grain emulsions contemplated for preparing
blended grain emulsion layers satisfying the require-
ments of this invention must be capable of providing
tabul~r grains satisfying the thickness and diameter
criteria which also provide at least 35 percent of
the total grain projected ares in the blended 8rain
emulsion l~yer. Thus, although the tabular graln
emulsions employed in the practice of this invcntion
preferably provide at least~50 percent of the total
grain projected area, at least before blending with
the second grain population, this i6 not essential if
. . 25 the 3.5 percent of the total gr~in projected are~
condition noted above in the blended grain emulsion
: layer is satisfied.
Thus, i~ is apparent that while high ~spect
ratio tabular grain emulsions are preferred for
prepsring the blended grain emulsions and in a highly
preferre~ form the blended gr~ln emulsions are
themselves high aspect rstio tabular 8r~in emulsions,
this is not necessary in ~11 instance~, and
departures can actually be advantageous for specific
applications. However, for simplicity the ensuing
discussion rel~ting to radiation sensitive t~bular
s
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grain emulsions is directed to the preferred hlgh
aspect ratio tabular grain emulsions, it belng
appreciated that ~he teachings are g~nerally applic-
able to tabular grain emulsions as herein defined.
The preferred high ~spect ratio tabular
grain silver haloiodide emulsions are those wherein
the silver haloiodide grains having a thickness of
less th~n 0.3 ~m (optimally less than 0.2 ~m) and
a diameter of at least 0.6 ~ have ~n aver~ge
10 aspect ratio of at least 12:1 and optimally at least
20:1. In a preferred form of the invention these
silver haloiodide grains satisfying the above
thickness and diameter criteria account for at least
70 percent and optimally at least 90 percent of the
total projected area of the silver halide ~rains. In
a highly preferred form of the inventio~ the blended
grain emulsions required by this invention al~o
satisfy the parameters set out for the preferred high
aspect ratio tabular grain emulsions.
It is appreciated that the thinner the
tabulsr grains accounting for a given percentage of
the projected area, the hig~er the average aspect
ratio of the emulsion. Typically the tabular gr~in~
have an average thickness of ~t least 0.03 ~,
al~hough even thlnner tabular gr~ins can in principle
be employed.
High aspect ratio tabular grain emulsion6
useful in the practice of this invention can have
extremely high average ~spect ratios. Tabular gr~in
average aspect raeios can be increased by increasing
average grain diameters. This can produce sharpness
advantages, bu~ maximum average grain diameters are
generally limited by granularity requirements for a
specific photographic application. Tabular grain
average aspect ratios can also or alternat~vely be
increased by decreasing average grain thicknesses.
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When silver coverages are held cons~ant, decreasing
the thickness of tabular grains generally improves
granularity as a dir ct function of increasing aspect
ratio. Hence the maximum average aspect ratios of
the tabular grain emulsions of thiE; invention ~re a
function of the maximum aver~ge grain diameters
acceptable for the specifie pho~ogrsphic application
and the minimum a~tainable tabular grain thicknesses
which can be conveniently produced. Maximum average
1~ aspect ratios have been observed to vary, depending
upon the precipi~a~ion technique employed and the
tabular grain halide composition. High aspect r~tio
tabular grain silver haloiodide emulsions with
average aspect r~tios of 100:1, 200:1, or even higher
~re obt~inable by double-jet precipitation procedures.
The tabular haloiodide gr~ins employed in
the practice of this invention contain in add~tion to
iodide at least one of bromide and chloride. Thus,
the silver haloiodides speciflcally contemplated are
silver bromoiodides, silver chlorobromoiodides, and
silver chloroiodides. Silver bromoiodide emulsions
generally exhibit higher ph~otographic speeds and are
; for this reason the preferred and most commonly
employed emulsions for candid photogr~phy.
Iodide must be present in the tabula-r silver
haloiodide grains in a concentration sufficient to
influence photographic performance. It is thu~
contempla~ed that at least about 0.5 mole percent
iodide will be present in the tabular silver halo-
iodide grains. However, high levels of iodide are
not required to achieve the advantages of this
invention. Generally the t~bular silver haloiodide
grains contain less ~han 8 mole percent iodide.
Preferred iodide levels in ~he tabular silver
hsloiodide grains are from 1 to 7 mole percen~ ~nd
optimally are from 2 to 6 mole percent. All of the
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above iodide mole percentages are based on ~otel
silver present in the tabular grains.
The r~diation sensitive tabul~r h~loiodide
grains required for the practice of this invention
are preferably provided by selecting from amon~ the
various high aspect ratio tabular grain emulsions
disclosed in Research Disclosure Yol. 225, January
1983, Item 22534; Wilgus et al U.S. Patent 4,434,226;
Kofron et al UOS. Patent 4,43~,520; Solber~ et al
lu U.S. Patent 4,433,048; Maskasky U.S. Patent
4,40~,463; and Maskasky U.S. Pa~ent 4,435,501; each
cited above.
The blended grain emulsion required for the
practice of this invention can be convenien~ly
: 15 provided by blending with a tabul~r gr~in silver
h~loiodide emulsion as described above a second grain
population consisting essentially of silver salt
which is more soluble than silver iodide. The silver
salt should be sufficiently insoluble that it is
capable of forming a grain rather than being present
in a solubilized-form. Useful silver salts can be
chosen from among those ha~ng a solubility product
constant in the range 9.5 to less than 16. Preferred
silver s~l~s are those having a solubility product
constant in the range of from 9.75 to 15.5, op~imally
from ll to 13. Unless otherwise stated9 all solu-
bility product constants are referenced to a temp~ra-
ture of 20~C. A discussion and listing of solubility
product constsnts for exemplary silver salts is
presented by James, Theory of the Photo&raphic
: Process, 4th Ed., Macmillan, 1977, Chapter 1,
Sections F~ G, and Hs pp. 5-lO.
It is preferred th~t the silver salt forming
the relatively fine grains be at least as soluble as
the mos~ soluble silver halide present ~n the
rsdiation sensi~ive tabul~r grains. For example,
L~L 5
when the tabular grains consist essentially of silver
chlorobromoiodide, ~he rela~ively fine grains
preferably consist essentially of sllver chloride or
silver chlorobromide as opposed to s.ilver bromide.
5 When radiation sensitive tabular silver bromoiodide
grains are employed 5 the relstively fine grfllns
preferably consist essentially of silver bromide,
silver thiocyanate, or a combination of both.
Advantages have been realized when silver bromide and
1~ silver thiocyanate grains are employed in combination.
Although ~he relatively fine grains consist
essentially of silver salt more soluble than silver
iodide, it is appreciated that less soluble silver
salts in small quantities that do not interfere with
15 effectiveness can be presen~. For example, it is
common to treat silver halide emulsions with soluble
iodide salt solutions in conjunction with spectral
sensitiza~ion and to employ 8S antifoggAn~s and
stabilizers compounds which form highly insoluble
silver salts. While such conventional treatments can
result in the adsorp~ion of small quan~ities of
silver iodide or one or more other highly in601uble
silver salts to the surfaces of the relatively fine
grains, such conventional emulsion treatments are not
~5 normally incompatible with the practice of this
invention.
The grains consistlng essentially of a
silver salt more soluble than silver isdide are fine
as compared ~o the tabular silver haloiodide grains.
In general, the permissible si~e of this second grain
popul~tion blended with the radiation sensitive
tabular grains is a direc~ function of the solubility
of the silver salt forming these grain6. The sesond
gra~n population in all ins~ances exhibi~s an average
grain diameter of less than 0.5 ~m and preferably
exhibits an average grain diameter of less than 0.3
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~m. Op~imally the second gra~n population exhibits
an average grain diameter of less than 0.1 ~.
Thus, the second grain population is optimally
provided by blending a conventional Lippmann emulsion
S with the radi~tion sensitive tabular grain emulsion
to produce the blended grain emulsion required for
the prActice of this invention. The minimum average
diameter of the second grain popul~tlon is limlted
only by synthetic convenience, typically being at
least about 0~05 ~m.
Any concentration of the second grain
population can be employed that is capable of
enhancing the photographic properties of the reversal
photographic elements. Minimum second grain popula-
tion concentr~tions can range from as low 8S about0.5 mole percent; b~sed on total silver in the
blended gr~in emulsion layer~ with concentrations
above about 1 mole percent being preferred and
concentrations above about 5 mole percent belng
optimum for maximizing photographic benefits. To
svoid inefficient use of silver salts m~ximum
concentrations of the seco~d grain population are
generally maintained below the concen~rations of the
silver haloiodide forming the radia~ion sensitlve
tabular grains--that ls, below SO mole percent, ba6ed
on total silver in the blended grain emulsion layer,
with most efficient utilization of silver occurring
at second grain concentrations below about 40 mole
percent.
It is generally most convenient to prepare
the emulsions requ~red for the practice of this
invention by blending a tabular silver haloiodide
grain emulsion and a separfltely prep~red emulsion
containing the relatiYely fine second grain popula-
tion. The relatively fine grain emulsion c n, for
example, take the form of a relatively fine grain
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silver chloride, silver bromide, or silver thio-
cyanate emulsion, the preparation~ of whish are well
known to those skilled in the art and form no p~r~ of
this invention. As prev~ously, no~ed the relatively
S fine grain emulsion is optimally a Lippmann emul-
sion. So long as the grain requ~remen~s identified
above are satisfied, either or both of the tabular
grain containing and reletively fine grain cont~ining
emulsions can themselves be ehe product of conven-
tional grain blending.
Apar~ from the blended grsin emulsionfeatures specifically described above ~he reversal
photographic elements of this invention can take any
convenient conventional form. The reversal photo-
graphic elements can t~ke the form of e~ther black-
and-white or color reversal photographic elements.
In a very simple form the reversal photo-
graphic elements according ~o this inven~ion can be
comprised of a conventional photographic support,
such ~s a transparent film support, onto which i6
coated a blended grain emulsion layer as described
aboYe. Although conventio~al overcoat snd subbing
layers are pre~erred, only the blended grsin emulsion
layer is essential. Following im~gewlse exposure,
- 25 silver halide is imagewlse developed to produce a
fLrs~ silver image, which need not be view~ble. The
firs~ silver image can be removed by bleaching before
further development when ~ silver or silver enhanced
dye reversal image is desired. There~fter, the
residual silver halide ls uniformly rendered develop-
able by exposure or by fogging. Developmen~ produce6
reversel image. The revers~l image can be ei~her
silver image, a silver enh~nced dye image, or a dye
image only, depending upon the specific choice of
conventional processing technique6 employed. The
production of silver reversal images i5 described by
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Mason, Photographic Processin~ ChemistrY, 1966, Fooal
Press Ltd., pp. 160-161. If a dye only image i6
being produced, silver bleaching is ususlly deferred
until after the final dye image is formed.
The reversal photographic elements of thls
in~ention are in a preferred form color reversal
photographic elements capable of producing multicolor
images - -e . g ., images th~t at least approxim~tely
replicate subject colors. Illustrstive of such color
1~ reversal photographic ele~ents are those disclosed by
Kofron et al U.S. Patent 4,439,520 and ~roet U.S.
Patent 4,082,553, each cited above. In ~ simple form
such a color reversal photographic element can be
comprised of a support having coa~ed thereon at least
three color forming layer units, including a blue
recording yellow dye image forming layer unit, a
green recording magent~ dye image forming layer unit,
and a red recording cyan dye image forming layer
unit. Each color forming layer unit is comprised of
a~ least one radia~ion sensitive silver halide
emulsion layer. In a preferred form of the inven~ion
at least one radiation sens~itive emulsion layer in
each color forming layer unit is comprised of a
blended grain emulsion as described above. The
25 blen~ed grain emulsions in each color forming layer
unit cRn be chemic~lly and spectrally sensitized as
taught by Kofron et al U.S. Patent 4,43~,520. In a
preferred form chemical and spectral sensitization
of the tsbular grain emulsion is completed before
30 blending with the second grain population~ which
therefore remains ~ubst~ntially free of sensitiæing
materials. One or more dye im~ge providing mater-
i~ls, such as couplers, ~re prefer~bly incorporated
in each color forming layer unit, but c~n alterna-
tively be introduced into the photographic elementduring processing.
9 ~3 L`L 5
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The following constitutes a specific
illustration of a color reversal photogr~phic element
according ~o this invention:
I. Photographic Suppor~
Exemplary preferred photographic supports include
cellulose acetate and poly(ethylene terephthalate)
film supports and photographic paper supports,
especially a paper support which is partially
acetylated or eoated with bary~a and/or ~-olefin
polymer, particularly a polymer of an ~-olefin
containing 2 to 10 carbon atoms, such as polyethyl-
ene, polypropylene, and ethylenebutene copolymers.
II. Subbing Layer
To facili~ate coating on the photographic support
it is preferred to provide a gelatin or other
conventional subbing layer.
III. Red Recording Layer Unit
At least one layer comprised of a red sensitized
blended grain high aspect ratio tabular grain silver
haloiodide emulsion layer~ as described in detail
above. In an emulsion layer or in a layer adjacent
thereto at least one conven~ional cyan dye image
forming coupler is included, such as, for example,
one of the cyan dye image forming couplers disclosed
in U.S. Patents 2,423,730; 2,706,684, 2,725,292,
2,772,161; 2772,162; 2,801,171; 2,895,826; 2,908,573;
2,920,961; 2,9767,146; 3,002,836; 3,034~92;
~; 3,148,062, 3,214,437; 3,227,554; 3,253,924;
3,311,476; 3,419,390; 3~458,315; and 3,476,563,
IV. Interlayer
At leas~ one hydrophilic colloid interlayer,
preferably ~ gelatin interlayer which includes a
reducing agent, 6uch a~ an aminophenol or an ~lkyl
subseituted hydroquinone, i~ provided to act as an
oxidized developing agent seavenger.
1~2 5 ~3 8 L~ 5;
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V. Green Recording Layer Unit
At least one layer comprised of a green sensi-
ti7ed blended gr~in high aspect ra~io tabul~r grain
silver haloiodide emulsion layer, as described ~n
detail abo~e. In an emulsion layer or in ~ layer
adjacen~ there~o at least one conventional magenta
dye image forming coupler is include~d, such as, for
example, one of the magenta dye image forming
couplers disclosed in U.S. Pa~en~s 2,725,292;
1~ 2,772,161; 2,895,826; 2,908,573; 2,920,~61;
2,933,391; 2,983,608; 3,005,712; 3,006,759;
3,062,653; 3,148~062; 3,152,896; 3,214,437;
39227,554, 3,253,924; 3,311,476; 3,419,391;
3,432,521; and 3,519,429.
VI. Yellow Filter Layer
A yellow filter layer is provided for the purpose
of absorbing blue light. The yellow filter lsyer can
take ~ny convenient conventionAl form, such as a
gelatino-yellow colloidal silver layer (i.e., a Carey
20 Lea silver layer) or a yellow dye cont~ining gelatin
layer. In addition the filter layer contains ~
reducing agent ac~ing as a~ oxidized developing agent
scavenger, as described above in connection with ~he
Interlayer IV.
VII. Blue Recording Layer Unit
At least one layer comprised of a blue sensitized
blended gr~in high aspect r~tio tabular grain silver
haloiodide emulsion l~yer, as described in detail
above. In an alternative form the tabular grains can
30 be thicker than high aspect r~tio tabul2r grains-
~that is, the thickness criteria for the gr~ins can be
incre~sed from O . 3 ~m to less th~n 0.5 ~m, 86
described above. In this lnstance the grains exhibit
more na~ive blue speed, whlch preferably is augmented
35 by the use of blue spectral sensitizers, although
this is not essen~clal, except for the highest
5 ~ 'B L'9~
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attainable blue ~peeds. In an emulsion layer or in a
layer adjacent thereto at least one conventional
yellow dye image f orming coupler is included, such
as, for example, one of the yellow dye image forming
couplers disclosed in U.S. Patents 2,875,057;
2,895,826; 2,908,573; 2,920,961; 3,14~,0~2;
3,227,55~; 3,253,924; 3,265,506; 3,277,155;
3,369,~95; 3,384,657; 3,408,194; 3,415,652; and
3,~7,928.
VIII. Overcoat Layer
At least one overcoat layer is provided. Such
layers are typically transparent gela~in layers and
contain known addenda for enhancing coating, handl-
ing, and photographic properties, such as matting
agents, surfactants, antistatic agents, ultraviolet
absorbers, and similar addenda.
As disclosed by Ko~ron et al U.S. Patent
4,439,520, the high aspect ratio tabular graln
emulsion layers show sufficient differences in blue
speed and green or red speed when substantially
optimally sensitized to green or red light that the
use of a yellow filter layer is not required to
achieve acceptable green or red exposure records. It
is appreciated tha~ in the absence of a yello~ filter
layer the color forming layer units can be coated in
any desired order on the support. While only a
single color forming layer unit is disclosed for
recording each of the blue, green, and red exposures,
it is appreciated that two, three, or even more color
forming layer units can be provided to record any one
of blue, green, and red. It is also possible to
employ within any or all of the blue, green, and red
color forming layer units multiple radiation sensi-
tive emulsion layers any, some, or all o$ which
satisfy the blended grain emulsion requirements of
this invention.
~,
~'
3L2 ~3 8L~5
In addition to the features described above
~h~ reversal photographic elemen~s can~ of coursel
contain other conventiona' features l~nown in the art,
which can be illustrated by reference to Rese~rch
Disclosure, Vol. 176, December 1978, Item 17643. For
example, the silver halide emulsions other than the
blended gr&in emulsions described can be ~hosen from
among those described in Paragraph I; the silver
halide emulsions can be chemically sensitiæed, as
1~ described in Paragraph III; the silver halide
emulsions can be spectrally sensitized, ~s described
in Paragraph IV; any portion of ~he elements can
con~ain brighteners, as described in Paragraph V; the
emulsîon l~yers can contain antlfoggants and
stabilizers, as described in Paragraph VI~ the color
forming layer units can contain color image Eorming
materials as described in Paragraph VII; the elements
can contain absorbing and scattering materi~ls, as
described in Paragraph VIII; the emulsion and other
layers can contain vehicles, as described in Para-
graph IX; the hydrophilic colloid and other layers of
the elements can contain ha'rdeners, as described in
P~ragraph X9 the layers. can contain coatîng aids~ 8S
described in Paragraph XI; the layers can contain
2S plasticizers and lubricants, as.described in.Para-
graph XII; the layers, particularly the layers coated
farthest from the support, can contain matting
agents, as described in Paragaph XVI; and the
suppor~s can be chosen from among those described in
30 Paragraph XVII. This exempl~ry listing of addenda
and features is not intended to restrict or imply the
absence of other conventional photographic features
compatible with ~he practice of ~he invention.
The photographic elements can be imagewise
35 exposed with any of various forms of energy, B~
illustrated by Resear~h Disclosure, Item 17643, cited
1~598~
-19-
above, Paragraph XVIII. For multicolor imaging the
photographic elements are exposed eo visible light.
Multicolor reversal dye images can be formed
in photographic elements according to this lnvention
5 having differentially spectrally se~sitized silver
halide emulsion layers by black-and-white development
followed by color development. Reversal processin~
is demonstrated below employing conven~ional reversal
processing compositions and procedures.
Examples
The invention can be better appreciAted by
reference to the following specific examples.
Coverages in parenthesis are expressed in grams per
square meter. The elements described were in each
lS instance, except ~s otherwise stated, exposed through
a step tablet for 0.02 second by a 500 watt 2850K
light source ~hrough a Wrstten 8- filter and
reversal processed wlth a 3 minute first development
step using the Kodak E-6 process. The Kodak
E-6~ process is described in the British Journal of
Photography Annual, 1982, pp. 201-203.
Element 1 (satisfying ~he invention)
The following layers were coated on a film
support in the order recited:
Layer 1
Gelatin (1,08)
Layer 2
A very high speed green sensitized high aspect ratio
tabular grain silver bromoiodide emulsion sonsisting
of (8) high aspect ratio tabular bromoiodide grains
(1.08) havlng an aver~ge aspect r~tiv of 18~ n
average tabul~r graln thickness of 0.1 ~m, and 8
bromide to iodide mole ratio of 97:3; (b) 0.08 ~m
silver bromide gr~ins (0.86) provided by blending
Lippmann emul 6 ion with a high aspect ratio tabular
grain silver bromoiodide emulsion providlng the
~2S~345
-20-
grains for (a); (c) gelatin (2.16); and (d) a msgenta
dye forming coupler, 1~(2,4,6~trichlorophenyl)-3-
{3-[~-(2,4,-di-tert-amylphenoxy)acetamido]benz-
amido}-5-pyrazolone (0~86).
Layer 3
Gelatin (1.08) and bis (vinylsulfonyl)methane hardener
at 1.75% by weight, based on total gelatin in all
layers.
Element 2 (not satisfying the invention~
Element 2 was identical to Element 1, except
that no Lippmann emulsion was blended ~o form Layer 2.
Element 3 (not satisfying the invention~
Element 3 was identical to Element 1, except
that the Lippmann emulsion was not blended in Layer
2, bu~ was partitioned into ~wo equal parts blended
into Layers 1 and 3.
The photographic performsnce of the color
revers~l photographic elements can be compared by
r~ference ~o Figure 2, which shows the characteristic
20 curves for Elements 1, 2, and 3 as curves El, C2, and
C3, respectively. In comparing curve El with curves
; C2 and C3 it can be seen t~at a higher maximum
: - density and contrast is realized and that a lower
density in the toe reg~on of the curve El is
realized. Ie is surprising th~t the psrtitioning o
the silver bromide Lippmann emulsion between the
overcoat and undercoat layers degrades photographic
performance so that lower maximum density and
contrast as well as ~ higher minimum density are
observed than when the Llppmann emulsion i8 entirely
absent. Further, it is highly surprising that the
partitioned Lippma~n emulsion produces a result just
the opposite of that produced by blending the
Lippmann emulsion with the high aspect ratio tabular
grain silver bromoiodide emulsion.
~L~59~3~5
-21 -
Element 4 ~not satisfy~ng the invention)
An element identic~l to Element 1 w~6
prepared, except th~t instead of blending a hlgh
aspect rstio tabular grain emulsion with the silver
5 bromlde Lippmann emulsion (a) a single ~et precipi-
t~ted, ammonia diges~ed silver bromoiodide emulsion
containing non~abular gr~ins of 0.54 1~ in mean
diameter Pnd a bromide to iodide mol,e r&~lo of
96.5:3.4 was substituted for the high aspect ratio
tabular grain silver bromoiodide emulsion and tb) the
coating coverage of the silver bromide grains was
reduced to 0.43 g/m 2 .
_lement 5 (not satisfying the invention)
: Element S was identical to Element 4, except
that no Lippmann emulsion w~s blended to form Layer 2.
Element 6 (not s~tisfyin~ the invention)
Element 6 was identical to Element 4, except
th~t the Lippmann emulsion cover~ge was increased to
0.86 g/m 2 and was not blended in Layer 2, but was
partitioned into two equsl p~rts blended into Layers
. 1 and 3.
: The photogr~phic p~rformance of the color
reversal photographlc elements can be compared by
reference to Figure 3, which shows the ch~racteristic
25 curves for.Elemen~s 4, 5, and 6 as curves C4, CS, and
C6, respec~lvely. In comparing ~he performance of
the elements it is appsrent that the blending of the
Lippman silver bromide grain6 in the nontabular
- silver bromoiodide emulsion h~d the effect of
markedly reduclng the speed of Element 4 as compared
to Elemen~ 1, presented by the dashed line curve El~
or Elements 5 and 6, represented by curves C5 ~nd
C6. It can be seen that lnclusion of the Lippmann
silver bromide emulsion in L&yer 2 of Element 4
resulted in an increase in maximum density end ~
slight increase in contrast ~s compared to Element 5,
~L25~5
-22 -
but the large loss of speed prevented any decrease in
~oe region density from being obtained. It is to be
further noted that the relationship of rurves C5 and
C6 is reversed from that expected from the relation-
5 ship of curves C2 and C3.
Element 7 ~not satisfyin~ the invention)
Element 7 was identical to ~Lement 4, except
that the single je~ ~mmonia digested silver bromo-
iodide emulsion exhibited a bromide to iodide mole
ratio of 93.7:6.3 and a mean grain diameter of 0.70
~m .
Element 8 (no~ satisfying the invention~
Element 8 was identical to Element 7, Pxcept
that no Lippmann emulsion W85 blended to form Layer 2.
Element 9 (not satisfyin~ the inven ion)
Element 9 was identical to Element 7, except
that the Lippmann emulsion coverage was increased to
0.86 g/m 2 and was not blended in Layer 2, but was
p~rtitioned into two equal parts blended into Layers
1 and 3.
The performance of Elements 7, 8, and 9 is
represented by curves C7, C~, and C9 in Figure 4. In
comparing the curves of Figures 3 and 4, it is
apparent that the relative performance of Elements 7,
8, and 9 is similar ~o that of E~ements 4, 5, and 6,
respectively.
Element 10 (not satisfying the invention)
The following layer6 were coated on a
transparent film support in the order recited:
Lsyer 1
A very high speed green sensitized high aspect ratio
tabular grain silver bromoiodide emulsion consi~ting
of ~a) high aspect ratio tabular bromoiodide grains
having an sversge aspect ratio of 18:1, an aversge
tabular grain thickness of 0.1 ~m, and a bromide to
iodide mole ratio of 97:3 (1.08); (b) gelatin (2.16);
~,~ 5~3 8L~L5
-23-
and (c~ a cyan dye forming coupler, 3~ (2,4,-
di-t rt-amylphenoxy)hexanamido]-2-heptafluorobutyr-
smidophenol (0.97).
Layer 2
Gelatin (0.97) and bis(vinylsulfonyl)methane hardener
at 1.75% by weight, based on total g~elatin in both
layers.
Element_ll (satisfy~g the invention)
Element 11 was identical to Element 10,
10 except that 0.054 g/m 2 of 0.08 ~m silver bromide
grRins in the form of a Lippmann emulsion were
blended with the high aspect ratio tabular gr~in
silver bromoiodide emulsion.
Element 12 (satisfying the invention)
-
Element 12 was identical to Element 11,
except that the coatlng coverage of the silver
bromide grains was approximately doubled to 0.11
g/ m 2 .
Element 13 (satisfying the invention)
2~ Element 13 was identical to Element 12,
except thae the coating coverage of the silv~r
bromide grains was doubled ~o 0.22 g/m2.
The performances of Element 10, represeneed
by curve C10, and Element 13, represented by curve
E13, are compared in Figure 5. It is apparent that
curve E13 demonstrates a higher maximum density,
threshold speed, and contrast and a lower toe region
density. Elements 11 and 12 exhibited performances
in~ermediate between those of Elements 10 and 13,
except that Element 11 exhib~ted a lower maximum
density ~nd no higher contrast th~n Element 10.
However, when the characteristie curves were ~ran~
lated to a superposed position at minimum exposure
(at the left hand edge of the plot) 3 it w~s apparen~
that the threshold speed and contrase increased
progressively as a dirsct function of Lippmann
~25~3~
emulsion inclusion, with Element lO exhibiting ~he
lowest ~hreshold ~peed and contrast and Element 13
exhibitin~ the highest threshold speed and contr~st.
Elements 14 through 17
The comparison described above with refer~
ence to Elements 10 through 13 was repeated, but with
O.2 to 0.4 ~m silver ~hiocyanate grains being
substituted for the silver b-romide grains. Silver
thiocyan~e concentr&tions are lis~ed in Table I.
lU The results for Element 14, represented by curv~ C14,
and Element 17, represented by curve E17, are ~hown
in Figure 6. Intermediate perform~nces were
exhibited by Elements 15 and 16. Element 14 does not
satisfy the requirements of the invention while
elements 15 through 17 do s~tisfy the requirements of
the invention.
Table I
Element Curve A~CN (g/m 2)
14 C14 None
2015 --- 0.055
16 --- 0.11
17 E17'~ 0.22
Element 18 (not satisfying the invention~
The following layers were coated on a
. 25 transp~rent film support in the orde~ recited:
Layer l
A very high speed green sensitized high ~spect ra~io
tabular grsin silver bromoiodide emulsion con~isting
of (a) high aspect ratio tabular bromoiodide grains
30 having an aver~ge aspect ratio of 18:1, an sver~ge
tabular grain ~hicknes 6 of 0.1 ~m, and ~ bromide to
iodide mole ratio of 97:3 (1.08); (b) gelatin (2.16~;
and (c) a cyan dye formlng coupler, 3-~ ~(2,4,-
di-tert-amylphenoxy)hexanamido]-2-heptafluorobutyr-
35 amidophenol (0.97).
~5
-25-
L~yer 2
A yellow filter layer co~prised of gelatin (O.S0~;
~-cyano-4-[N,N-bis(isopropoxycarbonyl~ethyl)]-
amino-2-methyl-4'-methanesulfonamidochalcone ~0.11);
and ~-cyano-4-~N-ethyl-N-(2,2,2-trifluoroethoxy-
carbonylmethyl~amino-2-methyl-41-propanes~lfonamido-
chalcone (0.08).
Layer 3
A very high speed blue sensitized high aspect r~tio
1~ tabular grain ~ilver bromoiodide emulsion consisting
of (a) high aspect ratio tsbular bromoiodide grains
(1.08) heving an average aspect ratio of 11.7:19 an
average tHbular grain thickness of 0.12 ~m, and a
bromide to iodide mole ratio of 97:3; ~b) gelatin
(2.16); and (c) a yellow dye forming coupler,
~-~4-(4-benæyloxyphenylsulfonyl)phenoxy]-~-
pivalyl-2-chloro-5-hexadecylsulfonamidoacetan~lide
(1 . ~1) .
Lsyer 4
20 Ultraviolet absorbers 3-(di-n-hexylamino)allylidene-
malonitrile (0.11) ~nd n-propyl-~-cyano-~-methoxy-
cinnamate (0.11), 0.08 ~m silver bromide grains
(0.12), gelatin ~1.36), and bis(vinylsulfonyl)me~hane
hardener at 1.75~h by weight, based on total gelatin
-25 in all layers.
Elements 19 and 20 (satisfyin~ the invention)
Elements 19 and 20 were identical to Element
18, except that the green sensieized high aspect
rstio tabular grsin emulsion forming Layer 1 ~lso
contained 0.11 and 0.22 g/m29 respect~vely, of 0.0
~m silver bromide gr~ins9 introduced by blending a
Lippmann emulsion. The time of development wa four
minutes 30 seconds.
The performances of Element 18, represented
35 by reversal charact2ristlc curve C18, and Element 20,
represented by reversal chr~cterist~c curve E20~ are
-26-
compared in Figure 7. A very pronounced increa~e in
maxim~m density, threshold speed, and contrast and a
very pronounced decease in toe region density is
observed for Elemene 20. The perform~nce of Element
19 was intermediate between that of Elements 18 and
20~ but nearer to tha~ of Element 20.
Elements 21 and 22 (satisfying ~he invention)
Elements 21 and 2Z were identical to Element
18, except that the green sensitized high aspect
lU ratio tabul~r grain emulsion forming Layer 1 also
contained 0.054 and 0.11 g/m2, respectively, of
0.2-0.4 ~m average diameter silver ~hiocyanate
grains.
In Figure 8 the reversal characteris~ic
15 curve E21 of Element 21 is compared with the reversal
characteristic curve C18 of Element 18. It can be
seen that maximum density and contrast are higher for
Element 21 than for Element 18. Element 21 exhibits
a much lower density in the toe region of the curve
2U than Element 18.
Elemen~ 22, which contained approximately
twice the coating coverage~of silver thiocyanate
grains exhibited differences from Element 18 that
were qualitatlvely similar to those exhibited by
25 Element 21, but the differences were larger in the
case of Element 22.
Element 23 (satisfying the invention)
-
Element 23 was identical to Element 18,
except ehat the green sensltized high sspect ratio
tabular grain emulsion forming Layer 1 al~o contained
0.11 glm2 of 0.2-0.4 ~m average diameter silYer
thlocyan~te grain~ and 0.22 g/m 2 of 0.08 ~m
sllver bromide grains.
The reversal characteristic curve E23
35 obtained for Element 23 is plotted in Figure 8. It
can be seen that a higher maximum den6ity and
-27-
contrast is realized ~s comp~red to corresponding
curves C18 and E21 representing Flements 18 ~nd 21,
respec~ively. Also a lower toe region density i6
refllized~
Element 24 (not satisfyan~ the invention)
An element similar to Element 14 was
prepared, exposed, and processed, except that the
emulsion layer additionally~con~ained silver iodide
grains of less than 0.1 ~m in av~rage diameter
1~ (0.11) as a result of blending in a Lippmann silver
iodide emulsion.
The chara~teris~ic curves from Element 14,
Curve C14, and Elemen~ 24, Curve C24, are comp~red in
Figure 9. From Figure 9 it is apparent that the
addi~ion of the fine silver iodide grains resulted ~n
an incre~ent~l incre~se in density at all levels of
exposure. Reduced toe region density was not
obtained, contrast incre~se was m~rginAl, ~nd minimum
density was increased. Thus, the ~dvantages of the
inven~ion are not realized by substituting silver
iodide grains.
Element 25 (not satisfyhn~ ~he inven~ion)
A control element w~s made by coating &
sulfur and gold chemically sensitized high speed red
spectr~lly sensitized high aspect r~tio tab~l~r gr&in
silver bromoiodide emulsion on a gelatin (4.89)
subbed film support. The tabular silver bromoiodide
grains had an average diameter of 1.6 ~m ~nd an
average thickness of 0.11 ~m. The silver coverage
w~s 1.46 g/m 2 and the gelatin coverage of the
emulsion lsyer was 2.15 g/m 2. The emulslon layer
W&S overco~ted with gel~tin (0.98), and ~he element
WR8 hardened with 1.57 percent by weight, based on
total gelatin, bis~vinylsulfonyl)meth~ne~ The film
support had a process removable carbon containing
antihalation lsyer of the type disclosed in Simmons
U.S. Pstent 2,327,828~
-28-
Element 26 (satisyin~ the inventlon)
An element was prepared ~imil~r to Element
25, ex~ept tha~ ~he silver coverage was increa6ed S
percen by weight by blending into the silver
5 bromoiodide emulsion before coating a Lippmann
emulsion h~ving silver bromide grains of 0.08 ~m
average diame~er.
Element 27 (satisfying the invention)
An element was prepared similar to Element
1~ 25, except that the silver coverage was increased 10
percent by weight by blending into the silver
bromoiodide emulsion befQre coating ~ Lippmann
e~ulsion having silver bromide gr~ins of 0.08
average diameter.
Element 28 (satisfylng the invention)
An element was prepared simil~r to Element
25, except that the silver coverage WA6 increa6ed 20
percent by weight by blending into the silver
bro~oiodide emulsion before coating a Lippm~nn
emulsion h~ving silver bromide gr~ins of 0.08 ~m
average diameter.
Elements 25, 26, 27, and 28 were ideneically
exposed ~nd proce~sed. The dried elements were
exposed (1/50 second 9 500 watts/2850K) through a - 25 0.61 neutral density filter and a Daylight V filter
plus a Wratten 23A- filter. After removal of the
antihalation layer, the elements were processed for
80 seconds in a black-and-white developer of the type
disclosed by Battagl;ni et al U.S. Patent 3,607,263,
30 Example 1, w~shed, exposed uniformly to red ligh~,
and processed in color developer sontaining a cyan
coupler, following ~ procedure like that of Example 1
of Schwan et al U.S. Patent 2,959,970.
The characteristis curves obtained for
Elemen~s 25 and 28 sre shown in Figure 10 as curves
C25 and E28, respectively. It can be seen that curYe
2 5 ~
-29-
E28 has a higher maximum density and con~rast than
. curve C25 and exhibits reduced density in the toe
region of the c~aracteristic curve. The ch&rac~er-
istic curves for Elements 26 and 27, not shown, fell
5 between the characteristic curves C25 and E28, but
nearer to E28.
The invention has been described with
par~icular reference to preferred embodlments
thereof~ but it will be understood that variations
and modifications can be effected within the spirit
and scope of the invention.
