Note: Descriptions are shown in the official language in which they were submitted.
37~
1 -
Pho-tographic Reco~ding Material For Diffusion Processes
And Useful Non-diffusing Sulfilimine Com~ounds
This invention relates to a photographic recording
material comprising at least one silver halide emul-
sion layer containing at least one non-diffusing com-
pound which through a reductioIl reaction, forms a
diffusible, photographically active compound, more
particularly a diffusi.ble dye i.or dif~usion transfer
processes.
The production of photographic images, particularly
dye images, b~ diffusion transfer processes has ~een
known for a long time, for example the production
of so-called instant color imayes. The photographic
recording ma-terials used for this purpose are, in prin-
ciple, similar in structure insofar as they contain
at least one photosensitive silver halide emulsion
layer and an image receiving layer. The dye image
is produced by incorporating, in the material
non-diffusing colox providing compounds from which,
after various chemical reactions, soluble or diffusible
dyes or dye precursors originate in image distribution.
The diffusible dyes or dye precursors thus formed
migrate into the image receiving laver where they
are fixed to form -the dye image.
Since -the dye image obtained in the image-receiving
layer is generally intended to b~ a positive image of
the original or of the subject which has been photo-
graphed, the composition of the photographic recor-
ding material has to be such that formation of -the
AG 1695
..... .. . . . . . .
~57~3SZ
-- 2 --
image is acc~mpanied by a reveLsal. The reversal
may take place either during exposure by using
a positive silver halide eMulsion or during the
image-wise formation of the dye by making use of suit-
able chemical color providing systems.
In view of the diffei-ent silver halide ernulsions
which may be used for dye transfer processes, photo-
graphic dye transfer materials may be divided lnto two
groups, namely those in which positive sllver halide
emulsion layers are used and others which contain nega-
tive silver halide emulsion layers.
In cases where positive silver halide emulsions are
used, it is necessary to employ dye systems of the type
which release a diffusible dye image-wise at the exposed
areas in proportion to the progress of the photographic
development. Compounds suitable for this purpose are the
so-called DDR compounds. Dye-forming systems of this
type are described in British Patent No. 904,364; US
Patents Nos. 3,227,550; 3,628,952; 3,844,785 and German
Offenlegungsschriftan Nos. 2,317,134 and 2,415,125. Using
photographic materials ~f this type, it is possible
to produce colored transfer images of considerable
quality. Nevertheles~, materiais and processes of the
type in question are attended by certain disadvan-
tages, for example a relatively long development time
and unsatisfactory stability OL the dye images formed.
For photographic dye transfer materials of the
other type which contain one or more negative silver
halide emulsion layers it is necessary to use those
~G 1S95
.. , , . _ .. ... .. . . ., _ _ .. . ... .. . . .. . . . _ . . _ . _ . . .. _ . _ .. .. .
~78~
coloring systems which lead to a reversal Gf the image~
i.e. initially non-diffusing color providing com-
pound should form, through the developrnent reaction
ta~in~ place during development of the exposed silver
halide emulsion layer or through a resultant reaction,
a diffusihle dye or dye precursor at the unexposed areas
which difuses into the image receiving layer where
i-t rorms a ~ositive dye image of the original.
Color providing compounds oE this type are, ~or
example, the so-called dye developer compounds. These
compounds are soluble and diffusible at alkaline pH-
values of the type which apply during photographic
development. In the areas where development takes place,
they react with the deveioper oxidation products and
are thus converted into a non-diffusing fGrm. Compounds
of this type are described, for example, in US Patent
No. 2.983,606 or US Patent No. 3,185,567.
Other coloring systems are based on rlon-diffusing
oxidi~able color providing compounds which bring
a~out a reversal of the image during release of the
dye and which may therefore be used in combination
with negative silver halide emulsions. Compounds such
as these are initially contained in non-diffusing form
in the silver halide emulsion layer or in an adjacent
layer. Because of their chemical consititution,
they are split up hydrolytically to form a diffusible
dye at the alkaline pH-values oE the phGtographic develop-
ment process. This cleavage reaction only takes place
in the unexposed areas because, in the exposed areas,
AG 1695
. . .
~7~35~
the compounds are oxidized by the c1eve:Loper oxida~ion
product and are t,hus converted into a non-cleavable
form. Compounds of this type ar.e describe~ in German
Offenlegung~schriften Nos. 2,402,900; 2,543,902 and
2,823,159.
Numerous advantages can be obtained with color-
~roviding compounds of this type which, through their
ballast groups, are initiall~ incorporated in non-
diffuslng form in the photog~aE~hic material. The com-
pounds describecl in German Ofenlegungsschrift
~o. 2,402,900 are compounds of the type which split
off diEfusible photographic~lly ac~ive compounds, par-
ticularly dyes or dye precursor3, by a so-called
intramolecular nucleophilic displacement reaction.
Another cGloriny system which leads to image re-
versal and which may therefore be combined with negative
silver halide emulsions is formed by non-di~fusing redu-
cibLe color providing compounds. These compounds,
through substitution with ballast groups, are present
in the form of non-diffusing oxidized compounds or,
more generaliy, in tha form o~ reducible compounds.
They react neither diractly nor indirectly with
oxidizing substances, for example the developer oxidation
product, so that resistance to diffusion in the exposed
areas cannot be influenced. However, they are reactive
towards reducing compounds, for example through direct
or preferably indirect reaction with unused photographic
developer whi~h is available in the unexposed areas.
In consequence of the reduction these compounds are
AG 1695
.. . .. . . .. . . . . . .. . . .. . . .. . . . .
~S7tl~l5~
split in such a way that they release a diffusible,
phot~graphically active compoulid, particularly a com-
pound forming a dye or dye precursor, which subsequently
diffuses into and is fixed in the image receivin~ layer.
In a particularly preferred embodiment, the last
mentioned compounds are used in combination with an elec-
tron donor precursor compound (ED-precursor compound)
which provides the electrons required for the dye-re-
leasing reaction. If, therefore, an ED-compoun~ or
ED-precursor compound is present in image~wise distri-
bution in the photographic ma~erial containing the
non-diffusing reducible color providing compounds,
diffusible photographically active compounds are re-
leased by ~he reaction of the ED-compound with the non-
dlffusing color providing compound, so that the diffu-
sible, photographically active compounds, particularly
dyes, are formed in the same imagewise distribution.
The reducible compounds afford various advantages
over the oxidizâble compounds which lie above all
in the fact that the release of the diffusible photo-
graphically active compounds can be better controlled,
thereby allowing color separâtion to be improved and
the formation of undesirable color rog to be suppressed.
Nevertheless, it is desirable Eurther to improve the
properties of coloring systems of this type which work
positively in combinatioll with negative silver halide
emulsions. If it is considered that formation of the
diffusible dye has to be preceded by a number of chemical
reactions, namely the photographic development reac-
tion and the reaction of the photographic developer
AG 1695
.. , . . . _ .. .. . . . . . .
~i7~35;~
-- 6
via the ED-compounds of ED-precursor cornpounds with
the color providing compound incorporated in non-dif~using
form, some of these reactions being relatively compli-
cated, and if it is further considered tha-t the various
reac-tions have to take place immediately after one another
to prevent the formatio~ of difusible dye in unwanted
areas, it will be appreciated that as mucz latitude as
possible is required, particularly in regard to the
choice o~ the various reaction components.
Another difficulty lies in the fact that the com-
pounds required for t.he various reactions mentioned
have to be able to be incorporated very easily into
photographic layers in order not to complicate production
of the photographic material. In addition, the compounds
required ~or the reaction are of course required to
be sufficiently stable. In particular, the dyes released
are required to be extremely fast to light.
Since some of the compounds involved in the above
mentioned reaction have a relatively complicated
chemical structure, it is also desirable to improve
the existing systems and to replace them by others which
are easier to obtain in terms oE chemical production.
The object of the present invention is to find new
cleavable compounds and to provide photographic materials
containing these new cleavable compounds. The new com-
pounds are intended to be able to be cleaved by
reduction and to be able to be incorporated in the
photographic material in non-diffusing form through
the installation of a ballast group. In addition, they
AG 1695
..... . . . . . . . . .. ..
~S71~Z
-- 7
are intended to contain the essential part of a photo-
graphlcally active molecule, preferably a dye molecule,
and to have such a structure that, after cleavage, the
photographica~ly active molecule becomes diffusible
whilst the rest of the mGlecule together with the ballast
group remains in non-diffusing form in the layer in
which the uncleaved cleavable compound was incorporaked.
The reductive cleavage mechanism characteristic
of the new compounds may be defined by the expression
"CR-compound" (Cleavage by Reduction). Accordingly,
this expression is used hereinafter.
The CR-cornpounds difer from the reducible color
providing compounds mentioned above as explained
in the following. The earlier men-tioned compounds have
first to be reduced and may then be hydrolysed by
B-cleavage. The resultant dependence upon the pH-value
may lead to disadvantages. By contrast, the CR-compounds
used according to the invention have the advantage
that cleavage actually takes place through the reaction
with the ED-compounds so that there is no need for
subsequent hydrolysis.
Accordingly, the photographic recording material
according to the invention is characterized by the
presence o a non-diffusing compound which is capable
of a reductive cleavage reaction with the release of
a diffusible, photographically active compound, parti-
cularly a dye. It is particularly preferred to use the
CR-compounds according to the invention in combinaiion
ith an ED-compound or an ED-precursor compound, the
AG 1695
., . , _ _. . .. . .. .. .... . . ... . . .. . . . . .. ... .
~ ~7~35Z
ED-compounds distributed ima~e-wise supplyiny the CR-
compound according to the invention with electrons and
thereby initiating the reductive cleavage reaction in
which the photographically act:Lve diffusible compound
is released imayewise.
The new cleavage mechanisrn, i.e. the reductive
cleavage reaction, characteristic of the new compounds
used in accordance with the invelltion has the major
advantage that it makes it possible for the mechanism
by which the release of the photographically active
compound is controlled to be considerably better in-
fluenced. This cleavage mechanism, or rather the
mechanism by which the photographically active compound
is released, functions with particularly advantage in
combination with organic reducing agents. The photo-
graphically active compounds, particularly dyes, to be
released are split of with the NH2-S02-groups which have
already proved to be effective in photographic trans-
fer processes of the type in question. The combination
with these organic reducing agents, i.e. with ED-com-
pounds or ED-precursor compounds, makes it possible
for the reaction velocities of the component reactions
involved in the overall reaction chain to be influenced
in a way which has not hitherto been possible, and
promotes the:forma~ion of relatively larger quantities
of the required diffusible photographically active com-
pound, particularly a diffusible dye.
The electron-accepting CR-compounds clea~able by
reduction which may be used in accordance with the
invention may in principle be characterized by the
AG 1695
, .. .. ... . , , _ . . . . .. .. .. ... .. . . _ ... . . . . . .
9 ~ 7~
followlng schematic structure:
(ballasted carrier) - (cleavable bond~ - (diffusible
group)
A "ballasted carrier" is understood to be that
part of a molecule to which the difusible group
is bonded through the cleavable bond and which re~ers the
compound incorporated in the photographic material re-
sistant to diffusion, even under alkaline development
conditions. In general, the ca:rrier contains long-chain
alkyl groups.
The chemical structure of the so-called ballast
groups in the non-diffusing compounds containing the
photographically active group is not critical ~ se.
The photographically active group preferably contains
enough solubilizi.ng groups to be suficiently difusible
after cleavage in an alkaline medium. In the context
o the invention, the term "non-difusing" has the
meaning normally associated with it in the photographic
field. "Non-diffusing compounds" are understood to be
compounds which, in an al~aline medium, are unable to
diffuse through the hydrophylic layers containing
gelatin for example as binder. The ballast groups
attached to the non-difusing compound for this purpose
contain at least 8 carbon atoms and preferably at
least 14 carbon atoms. A ballast group may even
consist of one or more groups by which R1 and R2 are
preferably substituted and which together contribute
towards the required resistance to diffusion. Thus
the same resistance to diffusion may also be obtained
for example by using two or more comparatively small
AG 1695
. _ .. . .. . . . . . . . . . . .
~7~Sf~
groups, particularly alk~l groups, Eor example alkyl groups con-
taining from 5 to 1.2 carbon atoms. It is possible in this way
to obtain the same resis-tance to di:Efusiorl as with on~ ballast
group con-taining for example a relatively long-chain alkyl group
with from 8 to 20 carbon atoms.
The expression "difEusible groupl' applies to -the photo-
graphically active part of the molecule, for example a dye form.ing
group which i5 made diffusible by the reductive cleavage reaction.
The two parts of the molecule which have just been men~
tioned are joined together by a reductively cleavable bond or
binding group.
During the development of the photographic recording
material, the CR-compounds used in accordance with the invention
react with the non-consumed ED-compound which is present in image-
wise distribution with reductive cleavage of the ballasted carrier
from the diffusible group. This, now independent, part of the
molecule containing the photographically active group or the dye
group subsequently diffuses into adjacent layers or into the
image receiving layer where it performs its characteristic photo-
graphic function. Conversely, no electrons are transferred by the
ED-compound to the electron accepting CR-compound in the exposed
areas, so that no diffusible photographically active compound is
released there.
~ he distribution of the ED-compound which takes place
in reversed proportion to the silver developed image-wise is
obtained in known manner, for example by image-wise consumption of
the ED-compound before the ED-compound is reacted with a CR-
compound. If
- 10 -
~lS7~35Z
the ED-compound performs the function oE a silver halide developer,
it is oxidized by the development of the exposed silver halide
and, in these parts oE the layer, loses its reactivity to act on
the CR-compound. In the case of those ED-compounds which are
also known per se, but which are not photoyraphic deve:Lopers, the
photographic developer actually present acts as an agent for
transferring electrons and, in its oxidized form, reacts with the
ED-compound before it has any opportunity to act on the CR-compound.
It is through this mechanism that the imagewise distribution is
obtained in the ~orm of an image reversal. It is this particular
reaction sequence, particularly using ED-precursor compounds,
which is preferred for the photographic material according to the
invention which contains the CR-compound.
By comhining the CR-compounds according to the invention
with suitable ED-compounds or ED-precursor compounds and photo-
graphic developers as electron transfer agents, it is possible to
bring about the component reactions involved in the overall reac-
tion chain substantially independently of one another. This pro-
vides dye image with outstanding densi~ , whilst at the same
time avoiding color fogging.
In addition, the compounds used in accordance with the
invention are distinguished by a relatively simple structure and
by simple methods of production.
The present invention relates to a photographic material
comprising at least one photosensitive silver halide emulsion
layer containing at least one non-
~, - 11 -
. .
~ ~ ~ W.
- 12 -
diffusiny compound Erom which a diffusible photographi-
cally active compound, preferably a dye or a dye precur-
sor, is released by a reductive cleavage reaction,
this non-difusing compound being a sulfili.mine compound
corresponding to the following formula I:
R2-S-N-S02-E~ (I)
in which
R1 and R represent the same or different aryl radicals
particularly phenyl, or polynuclear aryl
radicals such as naphthyl or anthracyl, at
least one of the aryl radicals carrying an
electron-attracting substituent in a position
ortho or para and optionally additional sub-
stituents in any position, and at least one
of the aryl substituents carrying a ballasting
group; and
R3 represents the residue of a diffus~ble photo-
graphically active compound, particularly
the residue of a diffusible compound provi-
ding an image dye.
Particularly useful compounds of the present in-
vention are those of the following formula II
AG 1695
... . . , _ . . .. . . .. . .
~57~3~2
- 13 -
(E ) k (D ) m
Il ~ E (II)
r
,~N-S02 -R4
(E ~l (D )n
in which
E represents -N02 in 2- or 4-position
E , E represent electron-withdrawing subs-tituents
in positions 2 or 4 (for E1) and 2' or 4'
(for E2), for example -N02, -CF3, -CN,
-S02CF3,carbalkoxy, aLkyl sulfo,nyl, sulfamoyl,
carbamoyl
D , D represent radicals conferring resistance to
diffusion;
R represents the radical of a diffusible dye
or dye precursor;
k,l,m,n each are O or 1; but m-~n > 1.
These definitions are sufficient to outline the
essential particulars of the structure of the CR-
compounds according to the in~ention. Additionally each
of the benzene rings shown may have condensed to it
preferably in 2,3-(or 2', 3'-)position a further
benzene ring and may carry additional substituents such
as halogen, hydroxy, acyloxy, alkoxy or acylamino in a
AG 1695
.. . . . . . . ...
~ S7~3SZ
- 14 -
position that is not already occupied by one of E,
E1, E2, D1 a~d D2
Tl~e sulfamoyl group and the carbamoyl group
mentioned in the definition.o~ E1 and E2 may be unsub-
stltuted or substituted at the N-atom with alkyl or
aryl. Also the N-atom may ~e t:hat of a cyclic amino
group (pyrroli.dino, piperidino, morpholino).
The alkyl portlon contained in any one of ~he
carbalkoxy, alkyl sulfonyl and alkyl substituted sulfamoyl
or carbamoyl groups mentioned in the definition of E1
and E2 or in any one of the additional substituents such
as alkoxy and acylamino may have up to 22 carbon atoms
and may carry further substituents such as halogen,
alkoxy, phenoxy.
Radicals which confer diffusion resistance are
radicals which allow the CR-compounds of the invention
to be incorporated in a diffusion resistant form in the
hydrophilic colloids normally used in photographic
materials. Organic residues which generally ~arry straight
or branched chain aliphatic groups generally having from
8 to 20 carbon atoms and which may also contain carbocyc-
lic or heterocyclic groups are preferably used for this
purpose. These residues are attached to the remainder
of the molecule either directly or indirectly, e.g.
through one of the following groups: -N~CO-;
-NH-CO-NH-; -NHSO2-; -NR-, in which R represents hydro-
gen or alkyl; -o-; -S-; or -SO2-. The residue which
confers diffusion resistance may in addition carry
groups which confer solubility in ~ater, e.g. sulfo
groups or carboxyl groups, and these may also be present
in an anionic form. Since the diffusion properties depend
AG 1695
,, . . ... . . . , ~ . . . . . . . . ..
~ ~LSi7~35~
- l5 -
on the molecular size of the compound as a whole, it
is sufficient in some cases, for example when t~e mole-
cule as a whole is large enough, to use short,er chain
groups as radicals conferring diffusion resistance".
A single radical conferring diffusion resistance having
at least 8 C-atoms may also be replaced by two or
more shorter radicals, for exarnple tertiary butyl or
isoamyl groups. Further, in the CR-compounds of the
present invention the functions of a radical conferring
diffusion resistance (D1, D2) on the one hand and of
one of the additional electron-withdrawing substltuents
on the other hand may be combined in the same substituent
when for example a radical conferring diffusion resis-
tance is contained in one of t~ carbalkoxy, alkyl sul-
fonyl, sulfamoyl or carbamoyl groups represented by
E1 or E2~ as may be the case in a -S02-NH-C16H3~3 group.
The resistance of a diffusible compound providing
an image dye as represented by R3 is preferably the
residue of a diffusible dye or dye precursor (R4).
The dye residues may in principle be residues from
any series of dyes, provided that they are sufficiently
diffusible to be able to diffuse through the layers of the
light-sensitive material to the image receiving layer.
The dye residues may be equipped with one or more alkali-
solubilizing groups for this purpose. Suitable alkali-
solubilizing groups include, inter alia, carboxyl groups,
sulfo graups, sulfonamide or sulfamoyl groups and such
alkali solubilizing groups may be pre-formed in the
CR-compounds of the invention or may be formed only
when the dye residue is release from the ballasted
carrier.
AG 1695
.... .. . . _ . . . ... . . . . . . . .. . .. .
~l57~
- 16 -
The following are examples of dyes which are par-
ticularly suitable for the process according to the in-
vention: Azo dyes, azome-thine dyes, anthraquinone dyes,
phthalocyanine dyes, indigoid dyes, triphenylmethane
dyes, including dyes in the form of metal-dye-complexes
or capable to form such complexes if contacted with
metal ions.
By residues of dye precursors are meant residues of
compounds which are converted into dyes by any of the
usual steps or by additional steps during photographic
processing, whether it be by oxldation or by coupling
or by exposure of an auxochromic group in a chromophoric
system, for example by saponification. Dye precursors
in this sense may be leuco dyes, couplers or dyes which
are converted into other dyes during processing. Where
it is not important to distinguish between dye residues
and residues of dye precursors, it is to be understood
that the term "dye residue" is also used to cover such
residues of dye precursors.
Examples of non-diffusing reducible CR-compounds
suitable for use in accordance with the invention are
given in the following:
AG 1695
.. . . . ... .. ..... . .. . . .. .... . . . ... . . . . ... . .. .. . . . . . . . . . . .. ..
35~
- 17 -
1. N02
~1 S~)2CFi3
O2SHN- ~ -S-NSO,- ~ N- ~
~ ~ 2
C16H33 SO -NH N
H
l2
2. COHN ~ ~ ~ ~ -NHCOCH3
Cl H~_C 1
o 3
Cl 4H29
H37C18
--3-NSo ~) 2 ~ N _~02N3--C-C33
(CH3~2N-S02_NH-
N02
AG 1695
. _ . _ _ _ _ . _ _ _ _ . .. ... . . . . . . . . . . .. .. .. . .. .. . . . . .. .. . ... .. ... .. .
. ...
~57~Z
- 18 -
4. NO~ O N ~-N=;~\~ OH
~;o -NH-~/>
~E) Sl - N-SO2~
~,
.1 C18H37
N02
N02
S' ¢~
H3C~ N N-~ so2 N ~
3~ 18 3 7
2 H2
AG 1695
71~5Z
-- 19 --
ocl 6 H33
~-S -~-N2
e N
S2- ~ -S02NH-~
7 ~\~
02CH3
N02
7. CH3-CONH OH
N=~
12
Ne
3 7C1 a ~-S-~_NO2
AG 1 6 9 5
.. _ . . . ..... .... . . .. . . . .. .. .. .. . . . . .
.. . . . . .. ..
~7~3~Z
-- 20 --
0~
N i
2CY'3
'' i~;)2
SO2CH
e ~=~ 50 2 -NH-~
~S -N-SO -~)
~LN, C~ 6H33
NO2 C~3
AG 1 695
. .. . . ..... ... . .. . . ..
7~5;2
- 21 -
0. NO
¢~ SO 2NH
S-N-S02~=~ N~N ~--OH
~¢~ (CH~ 2N2
2 5 12 NO
S02CH3
¢~ 02N~ N N
,SO 2NH
O S -N- S 2 - ~ '
~,
C1 5H3
N02
AG 1 695
....... . . .. _ .. , . . . _ .. . .. . . . . . . .. . . . ...... .... . .......... .....
~.~ 5i7~2
2 2
1 2 .
N02
CH3-NHCO N=N~ so2NH-~-so2-N-s IE~
~OH ¢~
¢~ NO Cl 2H25
1 3 .
NO
1 2
3 SO 2NH C -C~I
~ 5_N_o2s~NHso2(~ N~ 0}1 3
H2 5C 1 2/~) ( CH3 ) 2N-S02~NH
N02
AG 1695
~57~
-- 23 --
1 4 .
OH NO2
~ ¢~
~ ~ l
N NH-S02~ so2-N-s ~
¢~SO2CH3 NO2 12 25
N02
- ¢~ 02N-~SN=N -8- OH
E3 ~=~ SO ;~NH-
N-S0 2-
~
C 1 2 H 2 5
NO 2
AG 1 695
78S~
- 2~ ~
1 6 .
N02
/SO2NH C-CH3
N_so2_~~N=N~ OH CH3
(H3C) 2N-2SHN
Cl 3H37
17. N102 02CH3
2 ~ N N ~OH
,-N-502- ~-S02NH-~)
33 1 2
AG 1 695
. _ . ..... .... ... . ..... .. . ... . . . . . . ... .. . .. . . . . . . .. .. . .. . ...... ... . .
~157~52
-- 25 --
18. N2 S2CH3
02N/~ 02N~-N=N ~- OH
8-N S2- 13 so2
Cl 4E~2 9
19 .
S02CH3
2N ~i N=W ~ OH
~SO 2NH
~3S -N-SO2-~ =~
NO 2~
C H
1:5 31
AG 1695
, _ . _ . _ .. . .. .. .. . . . . . . ....... . . . . .. ..
~ ~7~5'~
- 26 -
~0 .
S02CH3
¢~N N2--~ N=N ~OH
/=~ S02NH-
~S N-SO ~ d
~\
1o C25H3'1
02N ~ ~ OC~ 2H25
2~3-so2-N~
N=N --OH
CH3S02 ~ ~ ~
,~ ~
N02
AG 1~95
~5~;2
- 27
22 .
N02
CH3(CH2)14COHN COOCH3 ~L $2CH3
02N--~--S ~ ~N ~--OH
S2~ S2 NH
23. CF3
I ~
eN HCONHC 1 6 H3 3
SO - ¢~ -SO NE~-Q
N=N ~H
CH3
N02
AG 1 695
. . .. . ..... .. . . . . . .. .... . .. . .
~L57~
28
2~ .
2N -~3N ~-NO 2
S2- ~) -S02
N= --OH
[~ S02C~[3
N02
25 .
C1 4H29
2 13 2
N-N ~ OH
N2 ~S2CH3
N02
AG 1695
~i7~ 2
- 29 -
NO
26, 1 2
OC 1 8tl3 7 S2 -N~l ~
2 N= OH
~C18~137
N02 N02
27. NO2
~3
~ON~I ~ S-NS02 ~N=N ~ C~)N~ICH3
C15~131 ~3 ~) ~ N~N
HO
C6H5
28. NO2
~3
C16t33 ~NHCOCtl3
N=N
OCH3
~-
~L~S7~,z
- 30 -
29 .
N02
~- NS02~ N-N ~ t~ 2 5)2
02N~ o2
2N~lC1 6f~33 C~13
30. OH
~ CONI-IC18~!37
oHCOCH2
N=N
OCH3
31 .
CONH (CH2) ~ 3 C5H1 1
(3 ~3
2 ~3 S02NH~
I 2// ~ OH
33 16 ~ S2CH3
y
N02
d~ ,
~5'7~
- 31 -
32 .
3 14 29
CONHC H
~,N---N~ 6 11
33 .
CF3
02N ~3
~E3 S-NS2 --~
502NH ~3--OU
2C 3
N02
..~'
~5~
34 .
IC ClSfl31
[~3
NSO~ N --N~ CONHC}13
N02 C61-15
c1l6~133
~j 2~ NHCOCH3
li~= N
N2 3
X
7~S2
- 33 -
The way in which the CR-compounds used according to
the invention function is illustrated by the Eollowiny
reaction scheme.
In the exposed areas of the photographlc material,
the reducing electron-yielding Er)-compound, which is
present in active contact with the CR-compound in the
photographic layer, is oxidized directly or indirectly
by the photographic development reaction. In this Eorm,
it is incapable oE reacting with the CR-compounds,
but in the unexposed areas the unchanged ED-compound
reacts with the CR-compound with reductive elimination
of the diffusible group, preferably a dye.
Reaction scheme for the example ofthe sulfilimine-CR-
compounds:
exposed areas
ED-compound I AgHal~ EDOx ~ Ag ~ HX
EDoX~ R -SO-N-SO2R no reaction
R
uneX~osed areaSl ~ e 3
ED-compound + R -S-N-S02-R
R2
e 3
R -S ~ S02R ~ EDoX
R2
AG 1695
..... __. _ ..... _.. _ . _ ,_ ..... _ _. _ .. -- _ _ . .. _ .. . . _ _ .. . . . . . . .. . . . .. ... ..
~57~352
- 34 -
A particular advantage of the CR~compounds used in
accordance with the invention lies in the ~act -that, a~
shown by the above reaction scheme, photographically
active compounds, particularly dyes, contalning a sul-
famoyl group are formed during the cleavage reaction in
the unexposed areas. Dyes such as -these can be fixed
particularly effectively in image receiving layers
containinq polymeric mordants. These and other advan-
tages of dyes containing a sulfamoyl group are des-
cribed in German Offenlegungsschrift No. 2,242,762 and
German Offenlegungsschrif-t No. 2,505,248. ~owever, the
coloring systems mentioned therein do not bring about
any reversal of image during dye ~ormation, so that they
have to be combined with direct-positive silver halide
emulsions for the production of positive dye trans-
fer images.
Although, in the case of the already mentioned
reducible color providing compounds of the type described
for example in German Offenlegungsschrift No. 2,809,716,
or of the type described in publis~ed European Patent
Application No. 4399, a reversal of image is brought
about by the cleavage mechanism, the dyes formed contain
amino or sulfinic acid groups which are less advantageous.
Another advantage of the CR-compounds, particularly
of the color providing sulfilimine compounds used in
accordance with the invention lies in the fact that
they may be stored virtually indefinitely in alkaline
medium and, hence, are superior in this respect to
most of the other reduci~le color providing compounds.
AG 1695
._
. ~ .. ~ . . . .. ..... .. . .. .. .. . . ... . . . .... . . . .. .. . . .. .. . . . ..... ... . . ..
..... .
~15~35'~
- 35 -
The production of some of the CR-compounds used
in accordance with the inventio~ id described in the
following. Other compounds which correspond to yeneral
formulae I or II are produced similarly. The dye part
of the CR-compounds corresponds in its constitution
to the dyes typically used in photographic materials
and processes where diffusible dyes are used.
The structures of the compounds were confirmed
by the usual physical methods, such as infra-red
analysis or mass spectrometry and are in accordance
with the splitting behaviour.
Compound 1
~2
~3
(~ S--NS02 ~
\~<æ2NH~
502N~ ND
2
N2
Stage 1
4-nitro-4;'-hexadecylsulfonylamino-diphenyl-sulfide
5 g of 4-amino-4'-nitrodiphenyl sulfide (0,02 mole)
AG 1695
. _, _ _ _ . _, _ _ , . , . _ _ _ _ _ . _ . .. , , , , , , ,, . ., , . , . . , , _, . .. , . ,, .. ..
, _ . . . . . . .
~l57~S;~
- 36 -
are dissolved in 70 ml of pyridi.ne, followed by the addi-
tion in portions at room temperature of 6.48 of hexa-
decylsulfochloride (0.02 mole). Stirring is continued for
4 hours, after which the mixture i5 poured into ice/hydro-
chloric acid, the deposit is washed with wa-ter and recrys-
tallized from methanol.
~ield: 10.25 g = 965 of the theoretical
M.p: 68-70C.
Stage 2
4-nitro-4'-hexadecylsulfonylamino-diphenyl-sulfilimine
mesitylate
5.4 g oE mesityl sulfonyl-O-hydroxyl amine (0.025
mole) (Y. TAMURA, I. MINA~IHAWA, M. IKEDA, Synthesis
1977, l) are dissolved in 30 ml of methylene chloride
and 10.7 g of the c.ompound of stage 1 dissolved in 40
ml of methylene chloride are added dropwise with stirring
at 0C. The reaction ~as over ater 4 hours. The solvent
was adsorbed, the residue was repeatedly suspended with
ether, decanted of and dried ln vacuo.
Yield: 13.9 g = 97.5% of the theoretical.
Stage 3 (compouna_1)
3.74 g of the mesitylate of stage 2 (0.005 mole)
are dissolved in 150 ml of methylene chloride, followed
by the addition of 3.12 g of 5-(3-chlorosulfonyl-phenyl-
sulfonamido)-4-(2-methyl-sulfonyl-4-nitrophenylazo)-1-
naphthol (0.005 mole). 138 g of potassium carbonate
dissolved in 150 ml of water are added dropwise with
vigorous stirring to this suspension at 0C.
AG 1695
.. .. . . .. . ..... . . . .. . .
85Z
- 37 -
After 2 hours, the two phases are separated, the methylene chloride solution
is washed witll dilute potassium carboncl-te solution and then with water until
the aqueous phase is colorless. The methylene chlor:ide solution :is dried and
concentrated and the residue is dissolved in a little ethyl acetate and pre-
cipitated with petrol. The deposit is extracted twice by boiling with petrol
and filtered off.
Yield: 4.7 g = 83% of tho theoretical
M.p.: 128-130C.
Compound 2
~ ~ NHCOCH3
10Cl ~ OCH2CONII ~ ~ ~ ~ OH
4~129 N = N
OCH3
Stage 1
4-nitro-4'-~2'-tetradecyl-4'-chlorophenoxyacetyl)-amino-diphenyl sulfide
A solution of 8.4 g of 2-tetradecyl-4-chlorophenoxy acetic acid
chloride ~0.021 mole) in 25 ml of acetone is added dropwise with stirring at
room temperature to a solution of 5.2 g of 4-amino-4'nitrodiphenyl sulfide
135~
- 3~ -
(0,021 mole), 2.54 g of N,N'-dimethyl aniline ~0.021 mole)
in S0 ml of acetone. After 2 hours~ the mixture is poured
onto ice water/HCL and extracted with ethyl acetate. The
ethyl acetate solution is dried, stirred with fuller's
earth and filtered off under suction over Theorit. Remo~al
of the solvent by distillatlon 'Leaves the above-mentioned
product behind.
Yield: 10 g = 82~ of the theore1:ical.
S-tage 2
4-nitro-4'-(2-tetradecyl-4'-chlorophenoxyacetyl)-amino-
diphenyl sulfilimine mesitylate
3.1 g (0.0053 mole) of the compound of stage 1 dis~
solved in 5 ml of methylene chloride are added dropwise
at 0C to a solution of 1.14 g of MSH Imesityl sulfonyl-
O-hydroxyl amine) (0.0054 mole) in 5 ml of methylene
chloride. The reaction was complete after 2 hours. The
solvent was distilled off and the residue was dissolved
in ether and precipitated with petrol.
Yield: 4.05 g = 92.5~ of the theoretical.
Stage 3 (compound 2)
0.45 g (0.0033 mole) of potassium carbonate dis-
solved in 1 ml of water is added dropwise with stirring
at room temperature to a suspension of 1.1 g (0.00133
mole of the mesitylate of stage 2 and 0.58 g (0.00133 mole)
of 8-acetylamino-5-chlorosulfonyl-2-(2-methoxyphenyl-
azo)-1-naphthol in 15 ml of acetone. Ater stirring
for 2 hours at room temperature, the deposit is fil-
tered off under suction, washed with water and acetone
and dried.
Yield: 1.0 g = 77.2 ~ of the theoretical
M.p.: 188-192C.
AG 1695
.. .. . .... . ...... .... ... .. .. . . .. ..... . ... .. . . . . ... .. . . ........ . . . . . . . . . .
..
~1 ~5'~ "'~
- 39 -
011
~50 . ~ ~3 N2
0~1
S~ge 1
4-(2'-nitrophenylthio)~hydroxy-2-(2'l, 4"-di-t-pentyl-phenoxybutyl~-naphthamide
8.9 g (0.019 mole) of 1-hydroxy-2-(2', 4'-di-t-pentyl-phenoxybutyl)-
naphthamide dissolved in 60 ml of chloroform are added dropwise at room
temperature to a solution of 4.75 g (0.025 mole) of 2-nitrobenzene sulfenyl
chloride in 40 ml of chloroform. The solution is heated under reflux for 3
days. The solvent is distilled off and the residue is crystallized with
petrol. Recrystallization from petrol.
Gross yield: 10~35 g.
Stage 2
4-(2'-nitrophenylsulfilimino)-1-hydroxy-2-(2",4" di-t-pentyl phenoxybutyl)-
naphthamide mesitylate.
~ 3~7~5f~
_ '10 _
~ he thioether of stage 1 is reac-ted in known
manner with MSH. Afker a reaction time of 3 hours, the
solvent is distilled off and the mesityLate is crystal-
lized with ether.
Yield: 95.8~.
M.p.: 182-185~C.
Stage 3 (compound 8)
2.65 g (0.003 mole) of the mesitylate of stage 2 and
1.88 g (0.003 mole) of 5-(3-chlorosulfonylphenyl sulfon-
amido)-4-(2-methyl sulfonyl-4-nitrophenylaæo)-1-naphthol
are suspended in 200 ml of ace-tone, followed by the
gradual addition at room temperature o 0.82 g (0.006
mole) of potassium carbonate dissolved in a little water.
The solution was stirred overnight and then concentrated
the residue was taken up in ethyl acetate and undis-
solved fractions were separated off, after which the
solution was concentrated again and the residue purified
by column chromatography over silica gel in toluene/
methanol (3:1).
Yield: 2,23 g = 61% of the theori~al.
.p. 183-190C.
In the same way as described for CR-compounds 1,2
and 8 other CR-compounds have been prepared and are
found to have melting points as indicated in the following
table.
AG 1695
-
..... . ... . . . . .. . _ . _ . ... _ _ _ _ _ _
3L~57~5Z
CR-Compound m.p. (C)
3 195-205
4 115-117
98-101
6 105-112
7 181-182
9 108~110
104-16~3
11 145-146
12 135-138
14 205-207
118-122
16 173-178
17 168-171
18 117-123
19 114-117
108-`109
21 120-123
22 104-106
24 248
2S 105-108
26 186-188
Since the:photographic recording material according
to the invention is preferably used for the production
of color photographs in natural colors, it preferably
has the structure required for this purpose and con-
tains a red-sensitive silver halide emulsion layer con-
taining a CR-compound which splits off a diEfusible
G 1695
.. .. . .... . . . . . .. ., . ... . . , .. . .. _ . ... . .
7~5~
~ 42
cyan image dye, a greerl--sensitive sil~er halide emul-
sion layer containlng a CR-compound which splits off a
diffusible magenta dye ancl a blue-sensitive silver
halide emulsion layer in which a diffusible yellow dye
is formed imagewise from the CR-compound.
However, the CR~com~ounds do not necessailv have to
be present in the silver halid ernulsion layer. The only
requirement is that they should be in effective con-
tact with that layer. This merely means that the CR-com-
pounds have to be arranged within or in relation to the
silver halide emulsion layer in such a way that the
entire reaction chain, beginning with the photographic
development of the exposed silver halide up to splittiny
off of the image dye, can be completed. Accordingly,
it is readily possible to arrange the non-diffusing
CR-compounds in separate layers which are of course
preferably adjacent to the silver halide emulsion
layers. Provision has to be made in known manner to
ensure that the CR-compounds whlch are associated with
a silver halide emulsion layer sensitive to a certain
region of the spectrum and which contain a corresponding
dye moiety that can be split off are not adversely af-
fect~ad by diffusing products of silver halide emulsion
layers of different spectral sensitivity. It is of
course important to ensure that the silver halide emul-
sion layers and adjacent layers - if any - containing
the CR-compounds are permeable to the photographic alka-
line developer.
The CR-compounds used in accordance with the invention
may be employed with advantage for color diffusion
AG 1695
Z
- ~3 -
processes which are sui-table for the production o~ so-
called instant color imayes. Processes and materials
of this type are known and are described in numerous
patent specifications. Reference is made for example
to the comprehensive observa-tions in published European
Patent Applica-tion No. ~399.
A photographic material suitable for the production
of instant color photographs is in principle made up
as follows: A photosensitive recording part containing
the silver halide emulsion layers of normal spectral sen-
sitivity and the color-matched CR-compounds;
an image receiving layer which is permeable both to the
alkaline deveLoper medium and also to the diffusihle
imaye dyes produced during the reductive cleavage reac-
tion; means for storing and uniformly distributing
the alkaline developer medium, preferably developer
pastes, within the photographic material, for example
in a container which is arranged and constructed in
such a way that the container opens under the effect
of pressure and the developer medium is uniformly dis-
tributed within the photographic material.
In this case, processing to form the colored imaye
is carried out by initially exposing the material image-
wise and then ditributing the alkaline developer fluid
or paste within the photographic recording material, an
ED-compound or ED-precursor compound and an electron
transfer agent, generally the photographic developer,
having to be present while the alkaline developer fluid
is performing its function. The silver halide in the
photosensitive layers is developed proportionately
AG 1695
.. _ _ , _ .. ,, . ... ... . . _ . . . . . . . . . _ . . ....... .. . . .
~57~
- 4~ -
to exposed areas whilst, in -the unexposed areas, the CR-
compound is cleaved by reduction in inverse proportion
to development and the diffusible, photographically
active compound (generally a dye) is release~.
This compound the diffuses imagewise into the image-
receiving layer.
In photographic instant-image materials o -the
type in question which have a so-called integral struc-
ture, a light-reflecting layer and an opaque light-
absorbing layer are preferably situated between -the image-
receiving layer and the photosensitive la~ers.
So-called integral structures such as these o the
photographic material were described in US Patents ~05.
2,543,181 and 3,053,659 and later in German Auslege-
schrift No. 1,924,430. These photographic instant-
image color materials are characterized in that develop-
ment and formation of the d~e image takes place outside
the camera and in that the dye image formed is exposed
and viewed from dif~erent sides of the photographic
material. The alkaline developer fluid is generally distri-
buted between the photosensitive silver halide emulsion
layers and a transparent cover sheet. In addition, opaci-
fiers, such as dyes or pigments, are added to the developer
fluid. In this way, the ~ormation of a light-impermeable
layer of the distributed developer, in combination
with the above-mentioned opaque light-absorbing layer
and re~lecting layer between the photosensitive layers
and the image-receiving layer, prevents unfavourable uni-
form exposure of the photosensitive layers after the
material has been removed from the camera. By taking
AG 1695
_ _ _ . . . . ... , . . . .. .. . , _ .. . .. . . . .. .. . . . . . .
- 45 -
certain measures, i-t is also possible with photographic
recording materials containing the CR-compounds accor-
ding to -the invention to obtain positive dye images
which are not dye transfer images but retained dye
images. Embodiments such as these are described for
example in German Offenlegungsschrift No. 2,809,716.
As mentioned earlier, the CR-compounds are used
in combination with an ED-compound in order to release
the diffusible, photographically active compound image-
wise by reductive cleavage. In the exposed areas, the
ED-compound is oxidized or inactivated imagewlse before
it is able to react with the CR-compound. In this way
reversal of the image is obtained during the reductive
cleavage of the CR-compound.
An ED-compound is generally understood to be a com
pound which is capable of reacting with the CR-compound
used in accordance with the invention.
The ED-compound is used in combination with an elec-
tron-transfer compound ~hereinafter referred to in short
as the ETA-compound). In this case, the ETA-compound
is intended to have the properties of a silver halide
developer. So far as its reducing effect upon the
silver halide is concerned, it is intended to be able
to have a stronger reducing efect than the ED-compound,
i.e. during the photographic development reac-tion, the
ETA-compound is consumed in the exposed areas before
it is able to react with the ED-compound. Because of its
lower reactivity with respect to the exposed silver
halide, the ED-compound, if it has photographic developer
properties, also has no opportunity to act during the
photographic development reaction. After photographic
AG 1695
~S7t3~i~
~ 46 -
development, -the unconsumed ~TA-compound is present in
the photographic material in imagewise distrlbution,
inversely to the exposed image, in the unexposed parts
of the layer assembl~ where no photographic development
has taken place, and is then able to react with the
ED-compound in these parts of the layer assembly.
In khis way, the component reactions belonging
to the overall reaction mechanism are differentiated
as a function of time in the sense that first the
photographic development reaction, then the imagewise
deactivation o the ED-compound and, finally, the
reductive cleavage of the CR-compound ~y reaction with
the ED-compound take place at separate times. This
required differentiation in time may be further improved,
for example by arranging the ED-compound and the CR-
compound in heterodisperse distribution in the photo-
graphic layer, for example in finely divided droplets
of a so-called oil former, whilst the ETA~compound is
contained in the hydrophilic layer binder.
In one particularly preferred embodiment, so called
ED-precursor compounds are generally understood to be
compounds which contain the reduction-active function
required for the reductive cleavage of the CR-compound
in chemically masked form. It is only at certain p~-
values that the ED-precursor compounds are converted
into ED-compounds which only then are capable of
reacting with the CR-compound. It is possible in this
way further to differentiate the component reactions
as a function of time and hence to obtain improved
possibilities of controlling the entire mechanism.
AG 1695
_ _ _ _ ~ _ . . . . . . . . . .... . . .. . . . ...
~Ls~ z
-- ~7 --
In general, suitable ETA-compounds are the usual
photographic developers, for example hydroquinone or
derivatives thereof, such as 2-5-dichlorohydroquinone
and 2-chlorohydroquinone î aminophenol compounds,
such as 4-aminophenol, N-methylamino-phenol, 3-methyl-A-
aminophenol or 3, 5-dibromoarninophenol; pyrocatechol
or derivatives -thereof, such as 4-cyclohexyl pyrocatechol,
3-methoxy pyrocatechol and 4-(N-octadecylamino)-pyro-
catechol; phenylene diamine developer.s, such as N,N-
diethyl-p-phenylene diamine, 3-methyl-N,N-diethyl-p-
phenylene diamine, 3-methoxy-N-ethyl-N-ethoxy-N,N-
diethyl-p-phenylene diamine, 3-methoxy-N-ethyl-N-ethoxy-
p-phenylene diamlne or N,N',N'-te-tramethyl-p-phenylene
diamine.
However, the preferred ETA-compounds are photographlc
developers o~ the 3-pyrazolidone type, for example
1-phenyl-3-pyrazolldone, 1-phenyl-4,4-dimethyl-3-pyrazo-
lidone, 4-hydroxymethyl.-4-methyl-1-phenyl-3 pyrazoli-
done, 1-phenyl-4-methyl-3~pyrazolidone, 1-phenyl-5-
methyl-3-pyrazolidone, 1-phenyl-4,4-bis-(hydroxymethyl)
-3-pyrazolidone, 1,4-dimethyl-3-pyrazolidone, 4-methyl-
3-pyrazolidone, 4,4-dimethyl-3~pyrazolidone 1-(3-chloro-
phenyl)-4-methyl-3-pyrazolidone, 1-(4-chlorophenyl~-
4-methyL-3-pyrazolidone, 1-(3-chlorophenyl)-3-pyrazolidone,
1-(4-chloxophenyl)-3-pyrazolidone, 1-(4-tolyl)-4-methyl-3-
pyrazolidone, 1-(2-tolyl)-4-methyl-3-pyrazolidone, 1-
(4 tolyl)-3-pyrazolidone, 1-(3-tolyl)-3-pyrazolidone,
1-(3-tolyl)-4,4-dimethyl-3-pyrazolidone, 1-(2-tri-
fluoroethyl)-4,4-dimethyl-3-pyrazolidone and 5-methyl-3-
pyrazolidone.
AG 1695
_ _, . . _ , . . . . . .. . . .. ....
~s7~
The ETA-compounds which act op-timally for a given
special system may readily be determinecl by standard
routine tests. It îs of course also possible to use combi-
nations oE several ETA-compounds.
The ETA-compounds or photographic developers may be
introduced in different ways into the reaction taking
place in -the photogxaphic material. For example they may
be added to the developer ~luid and may be used with
it in the usual way. They may also be completely or
partly added to one layer or to several layers of the
photographic material, for example to one or more
of the photosensitive .silver halide emulsion layers, au-
xiliary layers, intermediate layers or even image-re-
ceiving layers.
Suitable ED-compounds or ED-precursor compounds
are the compounds which have already been described for
this purpose. Some examples of these compounds are
given hereinafter.
The ED-compounds or ED-precursor compounds are
preferably introduced into the photographic material
in such a way, or the photographic material is made
up in such a way, that these compounds can only be
active for the formation of the particular component
colour image. As already mentioned, a photographic
recording material for producing color imayes in natural
colors contains three layer units for producing the
three component color images, namely a blue-sensitive
silver halide emulsion layer with means for forming
the yellow component color image, a green sensitive
AG 1695
., .. . ....... ... ... _ . ...
~1~5~78.j~
_ a,g
silver halide emulsion layer with means for for~llny
the magenta component color image and, finally, a layer
unit containing a red-sensitive silver halide emulsion
layer and means for formirlg the cyan component color
image. The ED-compounds or ED-precursor compounds are
used in such a way that they are only active in the layer
unit associated with them. This result may be achieved
for example by separating the respective lay~r units
by intermediate layers containing compounds for arresting
the ED-compounds or ED-precursor compounds. Another
way of limiting the effec-t of the ED-compounds or ED-
precursor compounds to ~he particular layer unit is to in-
corporate these compounds in non-diffusing form. This
is achieved by the usual means, for example by sub-
stitution with ballast groups, generally long-chain
alkyl radicals, or by incorporatio~ in heterodisperse
form in solution in socalled oil formers. The technique
required for this purpose is know~ from the introduction
of color couplers into conventional color photographic
materials.
As mentioned earlier on, it is of particular ad-
vantage to use so-called ED-precursor compounds. It is
possible in this way to achieve a particularly high
degree of image resolution and to avoid the formation
of color fogs. These requirements are of major im-
portance in reyard to the materials mentioned earlier
on for producing natural color images ~/hich comprise
several layer units for forming the necessary component
color images. The principle on which the action of the
ED-precursor compounds is based as described earlier
on. Because of their instability in alkaline pH-value
ranges, the ED-precursor compounds are converted
AG 1695
.. . . = _ ... _, _ .. _ . _ . _ . . _ , . _ . . . . . . . . .. . . . . ... . .
- so -
hydrolytically into the ED-cornpounds. In view of the
limited hydrolysis velocity of the ED-precursor compounds,
it i5 possible to select a particularly suitable ED~
precursor compound by choosing one fox the correspondin~
special reaction system and hence, optimally to control
the mechanism as a whole. In the exposed areas, the
ED-compound formed by hydrolysis of the ED-precursor
compound reacts immediately with the oxidized ETA-
compound (oxidized photographic cleveloper) and, as a
result, loses its ability to cleave the CR-compound by
reduction. During the reaction in question, the oxidized
developer substance is reduced and is thus available
for developing further exposed silver halides.
By contrast, in the unexposed areas, the ED-compound
formed hydrolytically from the ED-precursor compound
reacts immediately with the CR-compound, because no
oxidized photographic developer is available in the un-
exposed areas, with reductive cleavaye and formation
of the diffusible, photographically active compound,
preferably an image dye.
There ED-precursor compounds are used, it is again
of advantage to use them in non-diffusing form, i.e.
substituted by ballast groups, or in heterodisperse
distribution. As already mentioned, heterodisperse in-
corporation is obtained by dissolving the ED-precursor
compound in so~called oil formers and emulsifying
the organic solution into the aqueous casting solution
for the particular layer. The ED-precursor compound
and the CR-compound may be incorporated in separate
AG 169S
. _ . _ _ . _ _ ... _ . . .. . . ... . . .
~ :~ 57 ~ ~2
solutions, although in many cases it is of advantage to incorporate the ED-
precursor compound together with the CR-compolmd so that these two reactants
are present toge~her in the droplets of the oil former.
Since the reductive cleavage reaction again takes place at a certain
velocity dependent upon the nature of the reactants, it is possible by sui.tably
selecting the pair of reactants consisting of the P.D-compound and the CR-
compound to control the formation of the diffusible photographically active
compound and hence to obtain optimal results. The concentration of the ED-
compounds or ED-precursor compounds in the layer uni~s of the photographic
material may vary within wide limits. In general, concentration ratios of the
ED-compound or ED-precursor compound to the CR-compound o from 1:2 to 2:1
and preferably from 1:1 to 2:1 have proved to be suitable.
The following are examples of suitable ED-compounds or ED-precursor
compounds:
Co~pounds of the iso-oxazolone type _ cording to DE-OS
No. 2,80~,716
~l3cNcFl2cH2so2NHcl8H87
CO CH3
lCO~O
H3CNCH2cH2sO2NHGl8H37
57~3~2
- 52 -
Sulfonylaminonaphthols or ballasted p~ lene diamine
compounds
011
~ CoNll(cll2) -9- ~ C
ED 2 ~ C5Hll
S2~ NIIC()C15H31
rl-l2
ED 3
/~ \
(C~-12)4 C16~133
SO3~1
Non diffusing hydroquinone derivatives
QH
,~/ C18H37
ED 4
OH
0~1
~ C16 33
ED 5 H3C
OH
OH
H3C~ ~ C16H33
ED 6 tl3C
OH
;~
i7~2
- 53 -
0~1
E17C3 ~ C161133
ED 7H3C ~ c3 7
0~1
Masked aminophenol derivatives as ED-~r cursdr compou_ds
/co
3CN
ED 8H33C16 ~ CIICN
H7CB ~
OH
Benzofuranone _rivatives as ED-precursor c ~ompounds accordin~
to German Application P-30 06 268.1
/co
O
~ CHCOOC2H5
ED 9 H33C16 ~
;H7C3 C~3
OH
o~clo
H33C16 ~,~CH2
ED 10 ll l
H7C3 ~ CH3
OH
/co
33C16 ~ H
ED 11H7C3 ~ CH3
OH
llt.3 7~3S~
5~
o~
ED 12 ~133Cl6\~ clr(~ 2
~17C3~ -C~13
011
q CO
~ C~ICOOC2~15
ED 13 ~125C12~C12H25
0~1
o~ CO~
ED 14 H7C3/~J\ CH30tl
~ ~0 ~ N2
H33C16 ~c~
ED 15 H7C3 /~ CH3
ED 16 ~CO )~
H7C3 OH
. OH
.CO~3
ED 17 H33Cl$ C\13CH
H3CO
OH
';~
~.~57~ Z
- 55 ~
Mercapto co~o d_
ED 18 ~l29C14~ll
En 19 INIISO2 ~ Sll
C16~133
ED 20 31C15CNII ~ S~l
Preferred ED-precursor compounds for combination with the CR-compounds according
to the invention are 5-membered or 6-membered ~-lactones of phenol, the phenol
ring containing a hydroxyl group or an amino group bound to ~he benzene ring
in the 2-position or 4-position to the lactonized phenol group and the lactone
ring containing electron-attracting substituents which split up the lactone ring
by hydrolysis to form the ED-compound at pH-values of from 10 ~o 13.
ED-precursor compounds of this type are described in German Patent
Application P 30 06 268.1. Particularly preferred ED-precursor compounds such
as these are benzofuranone derivatives containing electron-attracting substi-
tuents in the lactone ring. ED-precursor compounds of outstanding significance
for use in combination with the CR-compounds according to the invention are
ED-precursor compounds of the same type as compounds ED 1~ to
z
- 56 -
to ED 17 which may be defined by the fo].lowing general
formula:
R4
III R3 ~ O O
HO l2 OH
in which
R represents a carbocyclic or heterocyclic aromatic
group;
R2, R3, and R4 which may ba the same or di~ferent represent
hydrogen, alkyl, alkenyl, aryl, alkoxy, alkylthio or
amino or R3 and R4 may together complete a ~used, parti-
cularly carbocyclic ring,
at least one of the substituents R1, R , R3 and R :con-
taining a diffusion-impeding ballast group with 10 to 22
carbon atoms.
The combination of these ED-precursor compounds
with the CR-compounds according to the invention makes
it possible for excelle~t color densities and color
images to be obtained with hardly any traublesome foggi~g.
The ED-precursor compounds are added to the photographic
layers as described in German Patent Application P
30 06 268.1.
A diffusible, photographically active radical
R3 in general formula I above for the CR-compounds used
in accordance with the invention is understood to be a
AG 1695
_
....... _ .. . . . ..... .. ..... .. . . . .
h
- 57 -
radical w~ich, af-ter cleavage by reduction, has a photo~
graphically active function in diffusible form in photo-
graphic recording processes.
Thus, this radical may repxesent a dye or a dye
precursor. In addition, this radical may even be split
off in foxm of a diffusible compound which is photographi-
cally active in another direction, for example as
stabilizer for avoiding fogging, as toner, as fixing
agent, as developer or development accelaxator, as
hardener, as silver halide solvent, as development in-
hibitor or the like. In the reductive cleavage reaction
corresponding to the reaction scheme given earlier on,
the diffusi51e, photographically active compound is
formed with an S02NH2-group from the bond to the
carrier radical.
Since the CR-compounds used in accordance with the
invention are particularly suitable ~or the production
of photographic color images, it is preferred to use
those C~-compounds containing a dye-forming radical
as the diffusible, photographically active radical. The
radical in question may be a radical which represents
a pre~formed dye, a so-called shifted dye or a dye pre-
cursor product. Suitable preformed dyes or dyes which are
subsequently formed are the dyes normally used for
photographic image dyes, for example azo dyes including
metallisable azo dyes and metallised azo dyes,
azomethine (imine) dyes, anthraquinone, alizarine, mero-
cyanine, quinoline and cyanine dyes and the like.
AG 1695
~s~
- 58 -
Suitable dye radicals are described in detail in
particular in German Offenlegungsschrift Nos. 2,242,762
and 2,5Q5,248.. Reference is also made -to German Offen-
legungsschrift Nos. 2,626,821 and 2,756,656 for yellow
dyes, to German Offenlegungsschrit Nos. 2,406,626;
2,406,627 and 2,503,443 for magenta dyes and to German
Offenlegungsschrift Nos. 2,406,653; 2,462,010 and 2,607,440
for cyan image dyes.
Suitable metallizable or metallized dyes as photo-
graphically active radicals for the CR-compounds used
in accordance with the invention are described in US
Patents Nos. 4,165,238; 4,165,987; 4,183,754 and
4,183,755.
So-called 'Ishifted dyes" are. understood to be dyes
of which the absorption properties undergo hypso-
chromic or bathochromic displacement when the dyes
are subjected to a change of medium, for example by a
change in the pH-value, or are modified chemically, for
example through the formation of metal complexes or
through the release of a substituen-t from the chromo-
phoric system of the dye, as described in US Patent
No~ 3,260,597. The "shifted dyes" are advantageous
because their absorption ranges lie initially outside
the photosensitivity range of the associated silver
halide emulsions, so that no reduction.in photosensiti-
vity is possible. It is only during processing, for
example in the image-receiving layer, that these dyes
are converted by the factors mentioned above into dyes
which absorb in the required absorption range of the
image dyes.
AG 1695
_ .. -- .. , , _ , . . . . . . ... ... . . .
'7~
59
"Diffusible, photoyraphically active radicals" which
are released in form of a d~e precursor compound during
cleavage by reduction are understood to be radicals which,
initially, are substantially colorless, but which are con-
verted by chemical reaction into an image dye during
photographic processinq. Suitable dye precursor radicals,
are, for example, oxychromogenic compounds or color
coupler radicals.
Diffusible color coupler radicals are released
imagewise in the usual way during cleavage by reduction.
Suitable color coupler radicals are the compounds
normally used in conventional color photography, such as
pyrazolone couplers for the production of magenta dyes,
open-chain ketomethylene compounds for the production
o yellow image dyes or phenol or naphthol derivatives for
the production of cyan image dyes. The image dye is
formed by standard reaction with an oxidized color
developer, particularly of the phenylene diamine type.
These oxidized color developers may be incorporated in
certain layers - according to function image-receiving
layers - preferably in non-diffusing form. When the
color coupler diffusing imagewise reaches these layers,
the required image dye is formed. So far as suitable
non-diffusing colo~ couplers are concerned, reference
is made to US Patent No. 3,620,747.
In the case of oxychromogenic compounds as diffusible
radicals releasable from the CR-compound, the compounds
in question are those which, initially, do not contain
any chromophoric groups and are therefore colorless.
AG 1695
, _ , _ _ _ . _ . . .. . . .. . . . .. . .. . .. ... . . ...... .. . .. . .. . .
7'8;~2
- 60 -
Having been split off, -they are also able to diffuse
into suitable layers where they are converted in~o the
image dyes, for example by oxidation under the effect
of air or by the addition of further oxidizing agents.
Oxychromoyenic compounds o this type are also known as
leuco compounds. Leuco compounds such as these are
known ~ se, for example leuco-indoanilines, leuce-
indophenols or leuco-anthraquinones. Reference is made
to US Patent N. 3,880,658.
CR-compounds containing radicals other than image~dye-
forming radicals as diffusible, photographically active
radicals are added to the photographic materials in the
same way as the CR-compounds which yield the image dyes
during cleavage by reduction, i.e. accordiny to the
nature of the photographically active radical in the
photosensitive silver halide emulsion layer or in adjacent
layers. Concentxatlons of from 0.01 to 1 g per m2 may
be used according to function and the required effect.
In the case of development inhibitors or stabilizers
as photographically active, diffusible radicals, the
CR-compounds are used in the photographic material
in such a way that they are able to act in contact
with the silver halide emulsions. Accordingly, the
development inhibitor or the stabilizer i~s formed
in image-wise distribution in the unexposed areas.
The result of this is that the formation of developed
silver, i.e. unwanted fogging, is effectively suppressed
in the substantially or completely unexposed parts of
the layer(s). Since the formation of developed silver
suppresses the formation of dyes by deactivation of
the ED-compounds or ED-precursor compounds, the simul-
taneous use of dye-forming CR-compounds with CR-compounds
AG 1695
_ . .
-- . . .. . ... . . . .. . . . .
- 61 -
which release development inhibitors promote dye ~or-
mation in the unexposed areas and, hence increase
image dye density.
As already mentioned, the advantage of the CR-
compounds used in accordance wit:h the invention is that
image reversal occurs during formation of the dye so
that negative silver halide emulsions may be used in
photosensitive layers. However, it is obvious that,
for special ~laterials which require a different type of
image reversal, the CR-compounds according to the
invention may also be used in combination with direct-
positi~e silver halide emulsions or reversal emulsions.
Despite the various potential applications of the
CR-compounds according to the invention, the most
important applicatlon is in the production of color
images. To this end, they are used in quantities which
have to be sufficient to obtain a dye image of ade-
quate density. Although the required color density de~
pends cn other factors, such as the thickness of the
layer and the absorption properties of the diffusible
dye released, it has nevertheless proved to be best
to use the CR-compounds in concentrations of from
10 5 moles per m2 and preferably in concentraticns of
from 10 4 to 2.10 3 moles per square metre.
The concentration ratios of the CR-compounds ac-
cording to the in~ention to the other components of
the reaction mechanism may be determined from case
to case by standard routine tests. In general, the
following molar ratios will sufficeO
AG 1695
__,_,,__ _ _ _ _.. _ _ _. __, .. ., . , . . . .. . . -- _ . . . .... . , , ., . . ., ,, . ~ . . . ... _
- 62 - g ~ ~7 ~2
1 mole of CR-compound: 1 to 5 moles of E~-compound: 2
to 20 moles of silver halide, preferably 1 mole of
CR-compound: 1.5 moles of ED-compound: 5 moles of
silver halide.
Although the most impo~tant use of the CR-compounds
is in the production of colored images by using the
image dyes splitt off by reduction, it is also possible
in principle to use the non-cleaved CR compounds left
behind in the original layers for producing colored
images by known additional measures.
The photosensitive silver halide emulsion layers
suitable for the photographic materials according to
the invention have the usual composition.
Silver chloride or silver bromide may be used as
the silver halides either individually or in admixture
and may have a silver iodide content of up to 10 mole
percent. The size of the silver halide grains may
vary within wide limits. In general, grain sizes of
from 0.3 to 5 ~m~are used.
The layer binders used are again the usual hydro-
philic polymeric binders permeable to aqueous alkaline
solutions preferably gelatin, although it may be
completely or partially replaced by other synthetic
hydrophilic polymers. It can be favourable, particularly
for dye transfer processes, to use for cartain pur-
poses hydrophilic colloid layers of the type whose
permeability to the diffusible compounds, particu-
larly the dyes, is dependent on the pH. Polymers
such as these are known ~ se for photographic ma
terils. They are distinguished by the fact that -they
AG 1695
, . . . . . ... _ . . . . . .. .. .... .. . . . . ... . . . . . .
~s~
- 63 -
contain acid groups. The known layer binders may also
be used for the lmage receiving layer. In general,
the layer binders in question here are the so-called
polymeric mord~nts which must be capable of arresting
the image dyes diffusing into this layer and pre-
venting them from diffusing any further. The image
dyes and the polymeric mordants may be adapted to one
another by suitable selection to obtain optimal
results.
As for the rest, the photographic materials may
have the usual composition or the production of dye
transfer ima~es and, in addition to the image receiving
layer and the photosensitive layers, may contain auxi-
liary layers known ~ se, for example of the type
which, after development and dye formation, lower
the pH-value within the layer assemblage. Layers and
measures such as these for controlling the reduction
in pH are known ~ se. It is a routine measure to
build up an optimal material for the particular purpose
in question with the assistance of known means.
Alkaline developer fluid or pastes of standard
composition are suitable for the development of the
photographic materials according to the invention.
Suitable developers are alkalis, for example alkali
metal hydroxides, particularly sodium hydroxide, or
carbonates or suitab1e amines, for example diethyl-
amine. The developers have a pH-value in the usual
range (preferably above 12). They contain the usual
developer compounds mentioned above. The viscosity
of the developers is increased by the usual additives,
AG 1695
, -- . _ _ .. _ .. . _ . .. ... _ ..... .. . . . . . . . . . . . .
7~ 2
- 6~
such as natural or synthe-tic polymers of relatively
high molecular weight.
The support layers used for the photographic
materials accordlng to the lnvention are again the
usual support layers, such as films of cellulose triace-
tate, polyesters, such as polyethylene terephthalate,
and others.
The CR-compounds and ED-compounds or ED-precurso
compounds used in accordance with the invention are
incorporated 1nto the required layers of the phokoyraphic
material by methods known per se. As mentioned above,
it is of advantage in many cases to introduce the above-
mentioned compounds into the hydrophylic layer binders
in heterodisperse form, for example using solvents and
suitable processes. ~eference is made for example to
US Patents Nos. 2,322,027 and 2,801,171. Suitable sol-
vnets are generally the solvents which are also used
for the incorporation of conventional color couplers,
for example tri-o-cresyl phosphate, di-n-butyl phthalate~
2,4-diamyl phenyl, or preferably dialkyl amides of
alkane acids containing from 8 to 22 carbon atoms, par-
ticularly dialkyl amides, such as diethyl amide, of
lauric or palmitic acid. Other suitable solvents are
described in the journal "product Licensing Index",
Vol 83, pages 26 to 29. In certain cases, it may
be favourable to use water-miscible organic solvents,
such as tetrahydrofuran, short-chain alkanols, such as
methyl alcohol, ethyl alcohol or isopropyl alcohol,
acetone, 2-butanone, N-methyl pyrrolidone, dimethyl
formamide, dimethyl sulphoxide or mixtures thereof.
AG 1695
_, _ _ _ .. _ _ .. .. .. . . .. ... ... ... . .. . . ... . . ... .. . . .. . . .. ...
- 65 -
The photographically active compounds may also be intro-
duced by means of so-called chargeable pol~mer la-tices.
These methods are generall~ known; cf. for example
German Offenlegungsschrift No. 2,541,274.
Photographic Example
A mordant layer, a light-reflecting layer and a
photosensitive silver halide emulsion layer were applied
in the following sequence to a transparent support
layer of cellulose trlacetate:
M ant Layer
3.75 g of a copolymer of 1 part of styrene and 1
part of maleic acid imide of N,N-dimethyl-N-hexadecyl
N-~J-amino propyl ammonium bromide were dissolved in
15 ml of ethanol and the resulting solution was
stlrred into 75 ml of a S~ gelatin solution and homo-
genized. After the addition of 2.6 ml of a 5% saponin
solution and 1 ml of a 2~ aqueous mucochloric acid
solution, the emulsion was adjusted to a standard cas-
ting viscosity (approximately 11 mPa.s) and
applied to the support by dip-coating at 40C.
Light-Reflecting Layer
A suspension of 42 g of TiO2 in 20 ml of water was
dispersed in 150 ml of a 8~ aqueous gelatin solution
to which 5 ml of a 5~ aqueous solution of sodium dodecyl
benzene sulfonate and 5 ml of a 5~ aqueous saponin solu-
tion had been added. After the addition of 1 ml of a
2% mucochloric acid solution, the dispersion was
adjusted to a viscosity of 13 mPa.s at 40C and applied
to the dried mordant layer by dip-coating.
AG 1695
_ _ _ . _ _ _ _ .. _ . , _ _ , .. . .. . . .. . .. . . . . ... .. . .. . . . .
7~ Z
- 66 -
Light-Sensitive Layer
1 mMole of CR-compound 1 and 1.5 mMoles, of
ED-compound 14 were dissolved :in 5 ml of ethyl acetate
and, Eollowlng the addition of 2 ml of pamitic acid
diethyl amide, the resultlng so].ution was emulsified
lnto 25 ml of a 5~ gelatin solution, to which 5 ml of
a S~ aqueous solution of sodium dodecyl benzene sulEonate
has been added, in a homogenizer at approximately 1000
r.p.m. The emulsion was filtered through a folded filter
and made up ko 75 ml with 5~ gelatin solution. Ater
the addition of 1 ml of a 2~ mucochloric acid solution,
32 g of a silver bromide gela-tin emulsion ready for
casting, containing 0.67 mole percent of AgI, were added
to the emuIsion. This silver gelatin bromide gelatin
emulsion had been prepared with 74 g of AgNO3 per kg
of emulsion. The silver: gelatin ratio was 1:1.1. The
mixtures were applied to the light-reflecting layer
described above at approximately 40C at a rate 5 metres
per minute.
After drying for 24 hours t several samples are
exposed through a grey step filter on the emulsion side
and developed at 18C with a developer paste of the
following composition applied in a layer approximately
300 ~m thick, stoped for 2 minutes in a 5% acetic acid
solution, briefly rinsed and then dried. For a first
sample the development time was 1 minute, and for a
second sample ~our minutes.
Developer
20 g of carbethoxy methyl cellulose were dissolved
with stirring in 800 ml of water. 40 g of solid NaOH,
1.5 g of the sodium salt of ethylene diamine tetra-
acetic acid, 11.5 g of borax, 1 g of sodium hexameta-
AG 1695
., . . . .. .. . ~ _ , . ... .. .. . . . . . .. . .
~7~;~f~
- 67 -
phosphate, 3 g of KBr, l.6 g o~ 1-phenyl-4-methyl-4-
hydroxymethyl-3-pyrazolidone cmd 0.1 g of 1-phenyl-
5-mercapto-1,2,3,4-tetrazole were then added to the
homogeneous solution. The solution was then made up
with water to 1000 ml (pH 13.8). The pH value is
reduced in degrees of 0.1 by additions of 5 ml of glacial
acetic acid.
CR-compound 1 and compound ~D 14 produce a
positive dye transfer of high color brilliance.
In the same way dye transfer images were prepared
from other CR-compounds. The color densities (Dmin
and Dmax) are listed in the following table.
Color density after
CR-compound color 1 min 4 min
min Dmax min _max
1 cyan 0,10 0,72
3 magenta 0 0,72 0,02 1,10
4 cyan 0,08 1,54 0,08 1,86
magenta 0,05 0,60
6 cyan 0,12 0,98 0,22 1,48
11 cyan 0,08 1,4 0,16 1,76
12 yellow 0,08 0,56 0,10 0,76
14 cyan 0 0~96 0,04 1,2
cyan 0,06 1,44 0,14 1,62
16 magenta 0 0,30 0 0,44
19 cyan 0,04 0,42 0,06 0,70
21 cyan 0,14 1,22 0,26 1,72
24 (*) cyan 0,24 1,06 0,38 1,26
cyan 0,04 1,20 0,10 1,62
AG 1695
..... _ .. _ _ .. . _ ... _ .. .. . ... ,, . ... . _ .. . .... . .. . . ... . . ...... .. .. .... .. . ... ... .
7 !3~
~ 6~ -
(*) CR-compound 24 does not contain a ballasting yroup
(color fog!)
A transfer of -the same color density is also ob-
tained when the tesk material is stored before develop-
ment in a heatiny cabinet (3 d, 57C, 5~ relative
humidi-ty3 or tropical cabinet l7 d, 35C, 85 ~ relative
humidity).
AG 1695
. _
.. . . . .. . ... ... . .. .
