Dye diffusion transfer process employing compounds that release sulfonamide dye providing radicals

Useful non-diffusible dye-giving compounds for the photographic dye diffusion transfer process are dye sulfonamides derived from enolamines or endiamines or tautomers thereof. The dye-giving compounds are oxidized by developer oxidation products and subsequently split under the conditions of alkaline development to release diffusible dyes. The compounds are of the following formula ##STR1## in which X is a dye moiety and R.sub.1, R.sub.2 and R.sub.3 have meanings given hereinafter.

This invention relates to a process for the production of colour 
photographic images on the dye diffusion transfer principle, and to a 
photographic material suitable for use in this process which contains new, 
non-diffusible dye-giving compounds. 
Among conventional processes for the production of coloured photographic 
images on the dye diffusion transfer principle, increasing significance 
has recently been acquired by those processes which are based on the use 
on non-diffusible dye-giving compounds, from which diffusible dyes or dye 
precursor products are split off imagewise during development and 
transferred to an image-receiving layer. 
Dye-giving compounds suitable for this purpose are, for example, the 
non-diffusible colour couplers described in DT-PS 1,095,115 which release 
a preformed dye, or a dye formed during colour coupling, in diffusible 
form during development as a result of a reaction with the oxidation 
product of a colour developer compound consisting of a primary aromatic 
amine. The choice of the developer compound required is of course limited 
to colour developers. 
In addition, reference is made in this connection to the non-diffusible 
dye-giving compounds described in DT-OS 1,930,215 in which a preformed 
latent diffusible dye radical is attached through a splittable hydrazone 
group to a radical rendering the molecule non-diffusible. These compounds 
cannot be regarded as colour couplers. It has also been found that the 
choice of developer compounds required for liberating the diffusible dye 
radical is by no means confined to the usual colour developers, and 
black-and-white developers, for example pyrocatechols, are equally 
suitable instead. 
In addition, DT-OS 1,772,929 describes non-diffusible coloured compounds 
with a special group which, during development, enters into an oxidative 
ring-closing reaction and, in doing so, releases a preformed dye radical 
in a diffusible form. The compounds covered by DT-OS 1,772,929 may be 
divided into two groups. The compounds belonging to the first group 
require, for development, a normal colour developer compound with whose 
oxidation product they couple and release the preformed dye radical in 
diffusible form in a subsequent ring-closing reaction. The compounds 
belonging to the second group are themselves silver halide developers and, 
accordingly, are able, even in the absence of further developer compounds 
in the oxidised form, to enter into the above-mentioned ring-closing 
reaction by which the diffusible dyes are released. 
Finally, reference should also be made at this juncture to the 
non-diffusible dye-giving compounds disclosed in DT-OS 2,242,762. The 
compounds in question are sulphonamido phenols and sulphonamido anilines 
which, after the oxidation reaction which takes place during development, 
are split under the influence of the developer alkali to release 
diffusible dyes. 
The above-mentioned dye-giving compounds all work negatively. In other 
words, where normal (negatively working) silver halide emulsions are used, 
the diffusible dye liberated is distributed imagewise in consistency with 
the negative silver image produced during development. In order, 
therefore, to produce positive dye images, it is necessary to use 
direct-positive silver halide emulsions or, alternatively, to apply a 
suitable reversal process. 
It is difficult to select, from conventional dye-giving compounds, suitable 
compounds which are satisfactory in every respect both in terms of 
adequate reactivity and in terms of adequate stability. They should not 
release the diffusible dyes during the actual alkaline development step, 
but only as a result of imagewise oxidation through the silver halide 
developed imagewise. On the other hand, the diffusible dyes should be 
released sufficiently quickly in the case of imagewise oxidation, in 
addition to which the diffusible dyes have to be rapidly transferred. 
Furthermore, the dyes should be able to be adequately fixed in the 
image-receiving layer and, last but by no means least, should show 
excellent spectral properties and outstanding stability with respect to 
light and heat. 
The object of the present invention is to provide new non-diffusible 
dye-giving compounds which combine adequate reactivity with the requisite 
stability and which, above all, enable a choice to be made from a number 
of compounds with suitably graduated reactivity through variation of the 
splittable group. 
The present invention relates to a photographic dye diffusion transfer 
process for the production of coloured images, in which a photographic 
material having at least one photosensitive silver halide emulsion layer 
and, associated with that layer, a non-diffusible dye-giving compound 
which, in oxidised form, is able to release a diffusible dye in an 
alkaline developer medium, is exposed imagewise and developed with a 
silver halide developer, the silver halide developer in oxidised form 
oxidising the dye-giving compound which, as a result of oxidation, is 
split by the developer alkali to produce an imagewise distribution of the 
liberated diffusible dye, distinguished by the fact that the 
non-diffusible dye-giving compound corresponds to the following formula: 
##STR2## 
in which X represents the radical of a dye or dye precursor, 
R.sub.1 represents --OR.sub.4 or NHR.sub.5 where R.sub.4 is hydrogen or a 
radical that may be hydrolysed under the conditions of photographic 
development, for example an acyl radical, and R.sub.5 is hydrogen, alkyl, 
aryl, acyl or a heterocyclic group, said alkyl, aryl, acyl and 
heterocyclic radicals defined for R.sub.4 and R.sub.5 include such alkyl, 
aryl, acyl and heterocyclic radicals which together with one of the 
substituents R.sub.2 and R.sub.3 complete a 5-, 6- or 7-membered 
heterocyclic ring containing at least one oxygen or nitrogen atom; 
R.sub.2 represents hydrogen, alkyl, aryl or a heterocyclic group including 
such alkyl, aryl and heterocyclic radicals which together with one of the 
substituents R.sub.1 and R.sub.3 complete a 5-, 6- or 7-membered 
heterocyclic ring or a nitrogen atom carrying two substituents; the first 
substituent is a radical selected from the group consisting of hydrogen, 
alkyl, aryl and acyl including such alkyl, aryl and acyl radicals which 
together with R.sub.1 complete a 5-, 6- or 7-membered heterocyclic ring 
containing at least one nitrogen atom; the second substituent is a radical 
selected from the group consisting of hydrogen and a radical that together 
with R.sub.3 completes a 5-, 6- or 7-membered heterocyclic ring and 
preferably a pyrrol, pyrazole or pyridone ring; but the two substituents 
at the nitrogen atom are not both at the same time hydrogen; 
R.sub.3 represents hydrogen, alkyl, aryl, a heterocyclic group, acyl, cyano 
or a radical that together with one of the substituents R.sub.1 and 
R.sub.2 completes a 5-, 6- or 7-membered heterocyclic ring; 
The alkyl radicals represented by or contained in one or more of the 
substituents R.sub.1, R.sub.2 and R.sub.3 include straight chain and 
branched radicals with up to 22 carbon atoms such as methyl, ethyl, 
isopropyl, tert.-butyl, n-butyl or octadecyl; the alkyl radicals may carry 
further substituents such as halogen, hydroxyl, alkoxy, carboxyl, sulfo 
and sulfonyl groups, for example alkylsulfonyl or arylsulfonyl. 
The aryl radicals represented by one or more of the substituents R.sub.1, 
R.sub.2 and R.sub.3 may be phenyl or naphthyl groups and may carry further 
substituents such as halogen, trifluoromethyl, alkyl, alkoxy, alkylthio, 
acylamino, acyl, carboxyl or sulfo. 
Where not otherwise stated the acyl radicals mentioned above under R.sub.1, 
R.sub.2 and R.sub.3 are understood to include acyl radicals derived from 
an aliphatic or aromatic carboxylic or sulfonic acids or from carbonic 
acid or oxalic acid mono esters or from carbamic or sulfamic acids which 
may be substituted at the nitrogen with alkyl or aryl. 
If R.sub.4 represents a radical that is hydrolysed under the conditions of 
photographic development, it may be any alkali labile or hydrolysable 
group well known to those skilled in the art, e.g. acetyl, mono-, di- or 
trichloroacetyl, perfluoracyl, pyruvyl, alkoxy acyl or nitrobenzoyl. The 
hydrolysable radical R.sub.4 may also be a radical which may be present as 
a substituent in one of the possible groups for R.sub.2 and R.sub.3. The 
radical R.sub.2 is, for example, a phenyl radical with, in the 2-position, 
a carbonyl group together with which it formally forms a benzoyl radical 
(R.sub.4). 
The heterocyclic radicals represented by or contained in one or more of the 
substituents R.sub.1, R.sub.2 and R.sub.3 include aromatic heterocyclic 
radicals such as pyridyl, furyl, thienyl as well as saturated heterocyclic 
radicals such as piperidyl, pyrolidyl, morpholyl. 
Any heterocyclic ring in the dye-giving compounds of the present invention 
which is completed by two of the substituents R.sub.1, R.sub.2 and R.sub.3 
may have condensed to it further rings such as a condensed benzo ring. 
This may be the case for example if an aryl group or an acyl group such as 
benzoyl is represented by or contained in one of the substituents R.sub.1, 
R.sub.2 and R.sub.3 and completes together with one of the other two 
substituents a heterocyclic ring. 
Examples of heterocyclic rings completed by R.sub.1 and R.sub.2 are 
phthalyl, imidazoline, benzimidazoline, benzdiazinone (quinazolinone), 
benzoxazinon, benzthiazole and benzoxazole. Examples of heterocyclic rings 
completed by R.sub.2 and R.sub.3 are quinolone, pyridone, indole, pyrrole, 
pyrazole and coumarin. Indole, pyrrole, pyridone and thiazole are examples 
of heterocyclic rings completed by R.sub.1 and R.sub.3. Examples of 
heterocyclic rings completed by R.sub.1, R.sub.2 and R.sub.3 are fused 
rings, such as pyrazolobenzimidazole or pyrazoloquinazolone. 
Examples of dye-giving compounds of the present invention are those of the 
following formula II 
##STR3## 
in which R.sub.1 is defined as above, 
R.sub.6 represents an aryl such as phenyl or acyl radical, 
R.sub.7 represents an alkyl or alkoxy radical with up to 22 carbon atoms, 
or an acylamino or arylamino radical; these radicals may have attached to 
them other radicals which also may be present in the corresponding 
substituents in pyrazolone color couplers, such as alkoxy, alkylthio, 
aroxy, sulfo, carboxyl, acylamino, sulfamyl and halogen. 
R.sub.1 and R.sub.6 together may complete a 5- or 6-membered heterocyclic 
ring, and preferably a benzimidazoline or quinazolinone ring. 
Other preferred examples of dye-giving compounds of the present invention 
are those of the following formula III 
##STR4## 
in which R.sub.2 represents hydrogen, alkyl, aryl or a heterocyclic group, 
and 
R.sub.8 represents one or more substituents selected from the group 
consisting of alkyl such as methyl, isopropyl or tertiary butyl, alkoxy, 
such as methoxy, halogen such as chloro, sulfamyl in which one or two of 
the hydrogens on the nitrogen may be substituted by alkyl, or sulfo 
The compounds according to the invention, which are referred to hereinafter 
as enolamine or endiamine derivatives, may of course also be present at 
least partly in their tautomeric form and, accordingly may be formulated 
as such. However, this does not apply to compounds in which R.sub.4 has a 
meaning other than hydrogen. It is pointed out that the dye-giving 
compounds according to the invention, as intact molecules, should not 
diffuse in the layers of the photographic material. To this end, they 
contain a ballasting radical, for example in one of the radicals R.sub.1, 
R.sub.2 and R.sub.3. 
The dye-giving compounds may be adequately resistant to diffusion even in 
cases where R.sub.1, R.sub.2 and R.sub.3 do not contain any relatively 
long alkyl radicals, because, even in this case, the molecule may be 
sufficiently large, depending upon the dye radical. Otherwise, it is 
possible to make the dye-giving compounds sufficiently resistant to 
diffusion by selecting radicals (R.sub.1, R.sub.2 and R.sub.3) of suitable 
size. 
Ballasting radicals are radicals which enable the compounds according to 
the invention to be incorporated in non-diffusible form in the hydrophilic 
colloids normally used in photographic materials. Preferred ballasting 
radicals are organic radicals which generally contain straight-chain or 
branched aliphatic groups and, optionally, also isocyclic, heterocyclic or 
aromatic groups generally containing from 8 to 20 carbon aoms. These 
radicals are attached to the remaining part of the molecule either 
directly or indirectly, for example through one of the following groups: 
--NHCO--, --NHSO.sub.2 --, --NR--, where R is hydrogen or alkyl, --O-- or 
--S--. In the present case at least one of the substituents R.sub.1, 
R.sub.2 and R.sub.3 or a heterocyclic ring completed by two of these 
substituents carries a ballasting radical. The ballasting radical may also 
contain water-solubilising groups such as, for example, sulpho groups or 
carboxyl groups which may even be present in anionic form. Since the 
diffusion properties are governed by the size of the molecule of the total 
compound used, it is sufficient in certain cases, for example if the total 
molecule used is large enough, to use even shorter-chain radicals as the 
ballasting radicals. 
Suitable dye radicals are, basically, the radicals of dyes belonging to any 
class, providing they are sufficiently diffusible to be able to diffuse 
through the layers of the photosensitive material into the image-receiving 
layer. For this purpose, the dye radicals may be provided with one or more 
water-solubilising groups. Suitable water-solubilising groups are, inter 
alia, carboxyl groups, sulpho groups, sulphonamide groups and aliphatic or 
aromatic hydroxyl groups. However, the sulphonamide group remaining in the 
dye after splitting leaves the dye molecule with a considerable tendency 
towards diffusion in alkaline medium, so that the presence of additional 
water-solubilising groups is not absolutely essential. Examples of dyes 
particularly suitable for use in the process according to the invention 
are azo dyes, azomethine dyes, anthraquinone dyes, phthalocyanine dyes, 
indigoid dyes, triphenyl methane dyes, and also metal complex dyes and 
coloured metal complexes. 
In the context of the invention, residues of dye precursors are the 
residues of compounds which are converted into dyes during photographic 
processing by the usual or by additional processing stages, whether by 
oxidation, by coupling or by liberating an auxochromic group in a 
chromophoric system, for example by hydrolysis. Dye precursors 
corresponding to this definition may be leuco dyes, couplers or even dyes 
which are converted into other dyes during processing. Providing a 
distinction between dye radicals and the radicals of dye precursors is not 
of essential significance, dye precursors are also intended to be covered 
by the generic expression "dye radicals" used hereinafter. 
Formula examples:

The following are examples of suitable dye-giving compounds according to 
the invention: 
##STR5## 
Preparation of dye-giving compound 2 
4.9 g of compound (I), whose production is described hereinafter, were 
suspended in 50 ml of pyridine, followed by the addition of 4.3 g of the 
dye sulphochloride: 
##STR6## 
The solution was heated to 45.degree. C. and then left to cool. Following 
the addition of 50 ml of water, the solution was stirred for 1 hour. The 
precipitate was filtered off under suction and washed with water. The 
residue was suspended in acetone, filtered under suction, washed with 
acetone and dried. 
Yield: 5.2 g of compound 2. 
Compound (I) corresponding to the formula: 
##STR7## 
was obtained as follows: 
20.7 g of the pyrazolobenzimidazole corresponding to the formula: 
##STR8## 
were suspended in 150 ml of glacial acetic acid, followed by the dropwise 
addition at room temperature of a solution of 3.3 g of NaNO.sub.2 in 12 ml 
of water. The suspension was then stirred for 2 hours and subsequently 
introduced into a solution of 22.6 g of Na-dithionite in 150 ml of water, 
followed by stirring for 30 minutes. After filtration under suction, the 
product was washed with water. The residue was suspended in 250 ml of 
methanol, followed by the addition of 250 ml of water. The product was 
then heated to boiling point, cooled, filtered under suction, washed with 
methanol and dried under nitrogen. 
Yield: 18.2 g. 
Compounds 1 and 3 are obtained in the same way as compound 2 by reacting 
compound (I) with the dye sulphochlorides corresponding to the formulae: 
##STR9## 
Production of dye-giving compound 4 
4.4 g of compound (II), whose production is described hereinafter, were 
suspended in 50 ml of pyridine, followed by the addition of 4.3 g of the 
dye sulphochloride used for the production of compound 2. The mixture was 
heated to 40.degree. C. until a solution was formed, stirred for 15 
minutes at 40.degree. C., and then cooled. 50 ml of water were added 
dropwise, and the precipitate was filtered off under suction and washed 
with water. The residue was suspended in acetone, filtered under suction, 
washed with a little acetone and dried. 
Yield: 5 g of compound 4. 
Compound (II) corresponding to the formula: 
##STR10## 
was obtained as follows: 
6.2 g of compound (III) (for production see below) were suspended in 170 ml 
of glacial acetic acid, followed by the addition in portions of 9 g of 
zinc dust. The whole was stirred for 1 hour at room temperature and then 
for 30 minutes at 40.degree. C., filtered under suction and washed with 
glacial acetic acid. The mother liquor was concentrated in vacuo and the 
greasy residue was stirred with 50 ml of methanol, filtered under suction, 
washed with methanol and dried under nitrogen. 
Yield: 5 g of compound (II). 
Compound (III) corresponding to the formula: 
##STR11## 
was prepared as follows: 
9 g of the pyrazoloquinazolone: 
##STR12## 
were suspended in 75 ml of glacial acetic acid, after which 1.65 g of 
NaNO.sub.2 were added and the mixture stirred for 4 hours with a positive 
nitrite reaction. After standing overnight, the product was filtered off 
under suction, washed with H.sub.2 O and dried. 
Yield: 7.7 g of compound (III). 
Production of dye-giving compound 9 
4.9 g of the dye sulphochloride used for the production of compound 2 were 
briefly boiled with stirring in 70 ml of anhydrous chloroform and 3.55 ml 
of anhydrous pyridine, followed by the addition of 5.0 g of 
4-hexadecyloxy-.omega.-aminoacetophenone hydrochloride. After boiling for 
a further two hours, the product was cooled. After undissolved components 
had been filtered off under suction, the solution was stirred twice with 
10 g of Kieselgel G, a product of the Merck Company, Darmstadt, and then 
filtered under suction. The silica gel residues were extracted with a 
little CCl.sub.4. The combined CHCl.sub.3 and CCl.sub.4 solutions were 
concentrated by evaporation in vacuo, and the residue was stirred with a 
little petroleum ether, filtered under suction and dried. Yield: 1.7 g of 
compound 9. 4-hexadecyloxy-.omega.-aminoacetophenone hydrochloride was 
obtained as follows: 
72 g of 4-hexadecyloxy acetophenone were dissolved in 350 ml of glacial 
acetic acid at 50.degree. C. 32 g of bromine were added dropwise with 
stirring in such a way that the internal temperature remained at 
50.degree. C. in the absence of heating. On continued stirring in the 
absence of heat, a deposit was precipitated. The deposit was filtered off 
under suction at room temperature, washed with water, dried in vacuo over 
KOH and dissolved in 250 ml of chloroform. The solution was freed from 
residual water with Na.sub.2 SO.sub.4 sicc. and filtered, followed by the 
addition of 28 g of hexamethylene tetramine. After standing overnight, the 
hexamethylene tetramine hydrobromide precipitated was filtered off under 
suction and substantially twice the volume of ethyl acetate was added to 
the filtrate. The precipitate was filtered off under suction, washed with 
ethyl acetate and dried. Yield: 51 g. 
The product thus obtained was dissolved under heat in 840 ml of ethyl 
glycol, followed by the addition at room temperature of 24.6 ml of 
concentrated hydrochloric acid. After a few hours' stirring at room 
temperature, complete dissolution occurred, followed by the gradual 
precipitation of a solid product. After standing overnight, the product 
was filtered under suction and dried. Yield: 34.2 g. Further material, if 
any, may be precipitated from the mother liquor with acetonitrile. It is 
of course possible to apply other methods which lead to the compounds 
according to the invention. For example, suitable compounds may be coupled 
with diazonium salts, reduced by known methods to form the corresponding 
enolamines or endiamines or their tautomers and reacted with dye 
sulphochlorides to form the compounds according to the invention. 
The dye-giving compounds according to the invention are incorporated by any 
of the usual methods in casting solutions for the layers of the 
photographic material. The quantity of dye-giving compound used per liter 
of casting solution varies within relatively wide limits, the most 
favourable concentration being determined by simple tests. For example, 
from 5 to 80 g and preferably from 20 to 40 g of the dye-giving compound 
are used per liter of the solution. 
The association between the non-diffusible dye-giving compound and silver 
halide which is necessary for obtaining the required effect may be 
obtained, for example, by introducing the non-diffusible compounds into 
the casting solutions from aqueous-alkaline solutions utilising the 
water-solubilising groups present. However, the non-diffusible dye-giving 
compounds may also be introduced into the layers by any of the known 
emulsification processes. Processes of this kind are described, for 
example, in British Patent Specifications Nos. 791,219 and 1,099,414 to 
1,099,417. It is also possible to prepare aqueous dispersions of the 
dye-giving compounds and to add them to the particular casting solutions. 
To this end, aqueous suspensions of the dye-giving compound are finely 
ground, for example by intensive stirring in the presence of sharp-edged 
sand or by applying ultrasonics. In another embodiment, it may be 
desirable for example to incorporate the dye-giving compounds together 
with silver halide and, optionally, developer substances in the layer in 
the form of so-called micro capsules, in which case two or more 
differently sensitised photosensitive silver halide emulsions and the 
corresponding non-diffusible compounds may be combined in a single layer 
in the manner of so-called mixed-grain emulsions, as described for example 
in U.S. Pat. Spec. No. 2,698,794. The non-diffusible dye-giving compounds 
may be accommodated in a photosensitive layer itself or in an adjoining 
layer. For example, a compound releasing a blue-green dye is associated 
with the red-sensitive layer, a compound releasing a magenta dye is 
associated with the green-sensitive layer and a compound releasing a 
yellow dye is associated with the blue-sensitive layer. 
In the context of the invention, "association" and "associated" mean that 
the mutual arrangement of silver halide emulsion and dye-giving compound 
is such that they may interact to allow imagewise consistency between the 
silver image formed and the imagewise distribution of the diffusible dye 
liberated. The associated dye-giving compound is best incorporated in the 
silver halide emulsion itself or in a layer adjacent to the silver halide 
emulsion layer, this adjacent layer preferably lying behind the silver 
halide emulsion layer (as seen in the direction of the incident light 
during exposure). 
The dye-giving compounds according to the invention are oxidised imagewise 
by developer oxidation products during development of the silver image 
and, under the influence of the developer or activator alkali, 
subsequently undergo a splitting reaction in which the dye radicals are 
liberated in diffusible form as dye sulphonamides. The usual photographic 
developer compounds may be used for development providing they are able in 
oxidised form to oxidise the dye-giving compounds according to the 
invention. The following are examples of suitable developers: 
hydroquinone 
N-methyl aminophenol 
1-phenyl-3-pyrazolidone 
1-phenyl-4,4-dimethyl-3-pyrazolidone aminophenols 
N,N-diethyl-p-phenylene diamine 
N-ethyl-N-hydroxyethyl-p-phenylene diamine 
3-methyl-N,N-diethyl-p-phenylene diamine 
N,N,N',N'-tetraalkyl-p-phenylene diamines, such as tetramethyl-p-phenylene 
diamine, triethyl sulphobutyl-p-phenylene diamine and 
1,4-bis-pyrrolidinobenzene, and reductones 
It is expressly pointed out that the choice of developer substances in the 
process according to the invention is not confined to colour developers. 
Instead conventional black-and-white developers may also be used, which 
may be regarded as an advantage by virtue of the lesser tendency of 
black-and-white developers towards discoloration. The developers may 
actually be present in the layers of the colour photographic material 
where they are activated by the alkaline activator liquid, or in the 
alkaline processing liquid or paste. Since the dye-giving compounds 
according to the invention themselves have developer properties, there is 
no need in individual case to use auxiliary developer compounds. In cases 
such as these, the dye-giving compound is directly oxidised by developable 
silver halide. 
Since the imagewise distribution of the diffusible dye released during 
development is consistent with the developed silver image, it is 
necessary, in order to produce positive coloured transfer images, to use 
direct-positive silver halide emulsions or, in cases where conventional 
negative emulsions are used, to apply a suitable reversal process. 
A reversal process of this kind is available in the silver salt dispersion 
process. Photographic reversal by means of the silver salt diffusion 
process for producing positive coloured images using conventional colour 
couplers is described, for example, in U.S. Pat. No. 2,763,800. 
Replacement of the colour couplers by the above-mentioned dye-giving 
compounds gives a photosensitive element which is suitable for the dye 
diffusion transfer process. A photosensitive element of this kind 
comprises, for example, at least one combination of a photosensitive 
silver halide emulsion layer and, associated therewith, a binder layer 
containing development nuclei for the physical development process and a 
dye-giving compound. 
During development, the exposed part of the silver halide is chemically 
developed in the photosensitive silver halide emulsion layer. The 
unexposed part is transferred by means of a silver halide solvent to the 
associated binder layer containing development nuclei where it is 
physically developed. In cases where physical development is carried out 
with a developer which, in oxidised form, is able to release a diffusible 
dye as a result of a reaction with the dye-giving compound present in this 
layer, diffusible dyes are distributed imagewise and may be transferred to 
an imgae-receiving layer where they form a positive coloured image. 
In cases where reversal is carried out with compounds which release 
development inhibitors in imagewise arrangement, the photosensitive 
element consists of at least one layer combination of a photosensitive 
silver halide emulsion layer and a second emulsion layer which can be 
developed without exposure and which contains the dye-giving compound. The 
photosensitive silver halide emulsion layer is developed for example with 
colour developers in the presence of certain compounds which release 
development-inhibiting substances during the reaction with oxidised colour 
developer. The development-inhibiting substances released imagewise in the 
photosensitive layer diffuse into the adjacent emulsion layer developable 
without exposure where they inhibit development in an imagewise 
distribution. The non-inhibited (positive) parts of the emulsion layer 
developable without exposure are developed by the residual developer whose 
oxidation products subsequently react with the non-diffusible dye-giving 
compounds according to the invention to release diffusible dyes which are 
transferred imagewise to the image-receiving element. Suitable compounds 
which release development-inhibiting substances on reaction with colour 
developer oxidation products are, for example, the known DIR couplers 
(DIR=development inhibitor releasing), which are colour couplers 
containing a releasable inhibitor radical in the coupling position. DIR 
couplers of this kind are described, for example, in U.S. Pat. No. 
3,227,554. 
Another group of compounds which release development-inhibiting substances 
on reaction with colour developer oxidation products is described in U.S. 
Pat. No. 3,632,345. These compounds are not colour couplers. Accordingly, 
no dyes are formed on the release of the development-inhibiting 
substances. Finally, according to DT-PS 1,229,389, it is also possible in 
a process of this kind to use suitable substituted non-diffusible 
hydroquinone compounds which are oxidised into the corresponding quinones 
on reaction with developer oxidation products, releasing 
development-inhibiting mercaptans. 
In principle, suitable direct-positive silver halide emulsions are any 
direct-positive silver halide emulsions which need only be developed once 
to produce a positive silver image and an imagewise distribution of 
developer oxidation products corresponding to this positive silver image. 
For example, it is possible to use silver halide emulsions in which 
exposure to light or chemical treatment has resulted in the formation of a 
developable fog which is destroyed imagewise during imagewise exposure 
under certain conditions. The fog remains intact at the unexposed areas, 
so that a direct-positive silver image is obtained during subsequent 
development and, in consistency therewith, an imagewise distribution of 
diffusible dye is formed when a dye-giving compound according to the 
invention is associated with the direct-positive silver halide emulsion. 
Another group of direct-positive silver halide emulsions which may be used 
in accordance with the invention comprises the so-called unfogged 
direct-positive silver halide emulsions which are photosensitive 
predominantly inside the silver halide grains. When emulsions of this kind 
are exposed imagewise, a latent image is formed predominantly inside the 
silver halide grains. However, the development of unfogged direct-positive 
silver halide emulsions of this kind is carried out under fogging 
conditions where a fog is produced predominantly at the unexposed areas 
and a positive silver image is developed during development. The unfogged 
direct-positive silver halide emulsions are characterised by the fact 
that, when developed with a typical surface developer of the following 
composition: 
______________________________________ 
p-hydroxy phenyl glycine 
10g 
sodium carbonate (crystallised) 
100g 
made up with water to 1000ml 
______________________________________ 
exposed samples preferably form no silver image, or only a silver image of 
very low density, whereas in cases where an internal developer of the 
following composition: 
______________________________________ 
hydroquinone 15g 
monomethyl-p-aminophenolsulphate 
15g 
sodium sulphite (anhydrous) 
50g 
potassium bromide 10g 
sodium hydroxide 25g 
sodium thiosulphate (crystallised) 
20g 
made up with water to 1000ml 
______________________________________ 
is used, a silver image of adequate density is formed. 
Selective fogging of the unfogged direct-positive emulsions which have been 
exposed imagewise may be carried out before or during development by 
treatment with a fogging agent. Suitable forming agents are reducing 
agents, such as hydrazine or substituted hydrazines. In this connection, 
reference is made, for example to U.S. Pat. No. 3,227,552. 
Unfogged direct-positive emulsions are, for example those which show faults 
inside the silver halide grains (U.S. Pat. No. 2,592,250), or silver 
halide emulsions with a layered grain structure (DT-OS 2,308,239). 
The emulsions may also be chemically sensitised, for example by the 
addition during chemical ripening of sulphur-containing compounds, for 
example allyl isothiocyanate, allyl thiourea, sodium thiosulphate and the 
like. Other suitable chemical sensitisers are reducing agents, for example 
the tin compounds described in Belgian Pat. Specifications Nos. 493,464 
and 568,687, and polyamines such as diethylene triamine or amino methane 
sulphinic acid derivatives, for example according to Belgian Pat. 
Specification No. 547,323. 
Other suitable chemical sensitisers are noble metals and noble metal 
compounds, such as gold, platinum, palladium, iridium, ruthenium or 
rhodium. This method of chemical sensitisation is described in the Article 
by R. Koslowsky, in Z. Wiss Phot. 46, 65-72 (1951). 
The emulsions may also be sensitised with polyalkylene oxide derivatives, 
for example with polyethylene oxide with a molecular weight of from 1000 
to 20,000, and with condensation products of alkylene oxides and aliphatic 
alcohols, glycols, cyclic dehydration products of hexitols, with 
alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines 
and aliphatic diamines. The condensation products have a molecular weight 
of at least 700, preferably more than 1000. In order to obtain special 
effects, it is of course possible to use these sensitizers in combination 
with one another, as described in Belgian Pat. Specification No. 537,278 
and in British Pat. Specification No. 727,982. 
The emulsions may also be spectrally sensitised, for example by the usual 
monomethine or polymethine dyes, such as acid or basic cyanines, 
hemicyanines, streptocyanines, merocyanines, oxonols, hemioxonols, styryl 
dyes or other even trinuclear or polynucelar methine dyes, for example 
rhodacyanines or neocyanines. Sensitisers of this kind are described, for 
example in F. M. Hamer's book "The Cyanine Dyes and Related Compounds" 
(1964), Interscience Publishers, John Wiley and Sons. 
The emulsions may contain the usual stabilisers such as, for example, 
homeopolar or salt-like compounds of mercury with aromatic or heterocyclic 
rings, such as mercaptotriazoles, single mercury salts, sulphonium-mercury 
double salts and other mercury compounds. Other suitable stabilisers are 
azaindenes, preferably tetra- or pentaazaindenes, more especially those 
substituted by hydroxyl or amino groups. Compounds of this kind are 
described in the Article by Birr in Z. Wiss. Phot. 47, 2-27 (1952). Other 
suitable stabilisers are inter alia heterocyclic mercapto compounds, for 
example phenyl mercaptotetrazole, quaternary benzthiazole derivatives, 
benztriazole and the like. 
Gelatin is preferably used as the binder for the photographic layers. 
However, it may be completely or partly replaced by other natural or 
synthetic binders. Examples of natural binders are alginic acid and its 
derivatives, such as its salts, esters or amides, cellulose derivatives, 
such as carboxy methyl cellulose, alkyl cellulose, such as hydroxy ethyl 
cellulose, and starch or its derivatives, such as ethers or esters or 
caragenates. Examples of synthetic binders are polyvinyl alcohol, 
partially hydrolysed polyvinyl acetate, polyvinyl pyrrolidone and the 
like. 
The layers may be hardened in the usual way, for example with formaldehyde 
or halogen-substituted aldehydes containing a carboxyl group, such as 
mucobromic acid, diketones, methane sulphonic acid esters or dialdehydes. 
Also other hardeners may be used as for example fast acting hardeners such 
as carbodiimide hardeners, carbamoyl pyridinium salts and 
carbamoyloxypyridinium salts. Reference is made in this respect to German 
Offenlegungsschriften 2,263,602; 2,225,230 and 1,808,685. 
The dye diffusion transfer process according to the invention is carried 
out with a photosensitive element containing one or more silver halide 
emulsion layers and the non-diffusible dye-giving compounds associated 
therewith, and with an image-receiving element in which the required dye 
image is produced by the diffusible dyes transferred imagewise. To this 
end, the photosensitive element and the image-receiving element must be in 
firm contact with one another for at least a finite period during the 
development time, so that the imagewise distribution of diffusible dyes, 
produced in the photosensitive element in consequence of development, can 
be transferred to the image-receiving element. Contact may be established 
after development has started. Alternatively, it may even be established 
before the beginning of development. This is the case, for example, where 
the dye diffusion transfer process is carried out with a material in which 
the photosensitive element and the image-receiving element form an 
integral unit, hereinafter also referred to as one-sheet material, which 
remains intact even after development is over. In other words, the 
photosensitive element is not separated from the image-receiving element, 
even after dye transfer. An embodiment of this kind is described, for 
example in DT-OS 2,019,430. 
A one-sheet material suitable for carrying out the dye diffusion transfer 
process according to the invention comprises, for example, the following 
layer elements: 
(1) a transparent layer substrate 
(2) an image-receiving layer 
(3) a light-impermeable layer 
(4) a photosensitive element with at least one photosensitive silver halide 
emulsion layer and at least one non-diffusible dye-giving compound 
associated therewith 
(5) a retarding layer 
(6) an acid polymer layer 
(7) a transparent layer substrate 
The one-sheet material may be assembled by separately producing two 
different parts, namely the photosensitive part (layer elements 1 to 4) 
and the cover sheet (layer elements 5 to 7) which are then placed 
layerwise on one another and joined together, optionally using spacer 
strips, so that a space large enough to accommodate a measured quantity of 
a working liquid is formed between the two parts. The layer elements 5 and 
6, which together form the neutralisation system, may also be arranged, 
although with the sequence reversed, between the layer substrate and the 
image-receiving layer of the photosensitive part. 
Means may be provided for introducing a working liquid between the 
photosensitive part and the cover sheet, for example in the form of a 
laterally arranged splittable container which, under the action of 
mechanical forces, releases its contents between two adjacent layers of 
the one-sheet material. 
An important part of the photographic material according to the invention 
is the photosensitive element which, in the case of a one-dye transfer 
process, contains a photosensitive silver halide emulsion layer and, 
associated therewith, a non-diffusible dye-giving compound. The 
non-diffusing compound may be situated in a layer adjacent to the silver 
halide emulsion layer, or in the silver halide emulsion layer itself, in 
which case the colour of the image dye is preferably selected in such a 
way that the predominant absorption range of the dye-giving compound is 
not consistent with the predominant sensitivity range of the silver halide 
emulsion layer. However, in order to produce multicoloured transfer images 
in natural colours, the photosensitive element contains three such 
associations of dye-giving compound and photosensitive silver halide 
emulsion layer, in which case the absorption range of the colouring 
compound is generally substantially consistent with the spectral 
sensitivity range of the associated silver halide emulsion layer. In this 
case, however, the colouring combination must be arranged in a separate 
binder layer behind the silver halide emulsion layer (as seen in the 
direction of the incident light during exposure) to ensure maximum 
sensitivity. 
The developer oxidation products formed during the development of a silver 
halide emulsion should of course only act on the associated dye-giving 
compound. Accordingly, the photosensitive element generally contains 
separation layers which effectively prevent the developer oxidation 
products from diffusing into other non-associated layers. These separation 
layers may for example contain suitable substances which react with the 
developer oxidation products, for example non-diffusible hydroquinone 
derivatives, or if the developer is a colour developer, non-diffusible 
colour couplers. In one preferred embodiment, therefore, the 
photosensitive element has the following structure (going downwards): 
blue-sensitive silver halide emulsion layer, 
layer containing a non-diffusible compound releasing a diffusible yellow 
dye 
separation layer 
green-sensitised silver halide emulsion layer 
layer containing a non-diffusible compound which releases a diffusible 
purple dye 
separation layer 
red-sensitized silver halide emulsion layer 
layer containing a non-diffusible compound releasing a diffusible 
blue-green dye. 
The silver halide emulsion layers may of course also be arranged in a 
different order, although in this case the associated layers containing 
the colouring systems must also be changed around so that the association 
remains intact. 
The light-impermeable layer arranged below the photosensitive element is 
permeable to aqueous alkaline treatment solutions and, hence, to the 
diffusible dyes. It has essentially two functions. Firstly, it is used to 
mask the image silver left after development in the originally 
photosensitive element, and the dye-giving compounds left behind as colour 
negative, so that it is only the positive dye transfer image which is 
visible through the transparent layer substrate of the photosensitive 
part. Secondly, it seals off the photosensitive element on the side of the 
image-receiving layer (downwards) in lighttight manner. This is of 
particular significance in cases where, after exposure, the one-sheet 
material is intended to be brought into contact with the alkaline 
processing mass in the camera itself, subsequently removed from the camera 
and developed outside the camera. 
Layers with adequate impermeability to light but with adequate permeability 
to diffusible dyes may be prepared for example with suspensions of 
inorganic or organic dark-coloured, preferably black pigments, for example 
with suspensions of carbon black in suitable binders, for example in 
gelatin solutions. In general, layers which are 0.5 to 2.mu. thick and 
which contain from 10 to 90% by weight (based on the total dry weight) of 
carbon black in gelatin are generally sufficient for guaranteeing the 
exclusion of light during development to an adequate extent. The particle 
size of the pigments used is relatively non-critical providing it does not 
appreciably exceed 0.5.mu.. 
In addition to the black pigment layer, the light-impermeable layer 
preferably comprises a white pigment layer arranged below the black 
pigment layer. The function of this white pigment layer is to cover the 
black layer and to provide a white background for the image. Any white 
pigments may be used for this purpose providing they have an adequate 
covering power in not excessive layer thicknesses. Examples of suitable 
white pigments are barium sulphate, oxides of zinc, titanium, silicon, 
aluminium and zirconium, and also barium stearate or kaolin. Titanium 
dioxide is preferably used as the white pigment. The white pigment used 
has to satisfy the same requirements as the black pigments in regard to 
binder, concentration and particle size. The thickness of the white 
pigment layer may be varied according to the required whiteness of the 
background. The white pigment is preferably used in layer thicknesses of 
from 5 to 20.mu.. 
Instead of the light-impermeable layer, it is also possible in accordance 
with the invention to arrange in the one-sheet material means for 
producing a light-impermeable layer of this kind between the 
photosensitive element and the image-receiving layer, for example in the 
form of a laterally arranged container with a working liquid containing a 
clouding agent (pigment) which, under the effect of mechanical forces, 
releases its contents between the above-mentioned layers so that a pigment 
layer of the kind in question is formed between them. 
The image-receiving layer consists essentially of a binder containing dye 
mordants for fixing the diffusible dyes. 
Preferred mordants for acid dyes are long-chain quaternary ammonium or 
phosphonium compounds or ternary sulphonium compounds, for example those 
described in U.S. Pat. Nos. 3,271,147 and 3,271,148. It is also possible 
to use certain metal salts and their hydroxides which form substantially 
insoluble compounds with the acid dyes. The dye mordants are dispersed in 
the receiving layer in one of the usual hydrophilic binders, for example 
in gelatin, polyvinyl pyrrolidone completely or partially hydrolysed 
cellulose ethers and the like. Some binders may of course also function as 
mordants, for example copolymers or polymer mixtures of vinyl alcohol and 
N-vinyl pyrrolidone, of the type described for example in DT-AS 1,130,284, 
and also polymers of nitrogen-containing quaternary bases, for example 
polymers of N-methyl-2-vinyl pyridine, of the type described for example 
in U.S. Pat. No. 2,484,430. Other suitable mordanting binders are, for 
example, guanyl hydrazone derivatives of acyl styrene polymers, of the 
type described for example in DT-OS 2,009,498. In general, however, other 
binders, for example gelatin, will generally be added to the last of the 
above-mentioned binders. 
Suitable transparent layer substrates for the one-sheet material according 
to the invention are any of the transparent substrates commonly used in 
photography, for example films of cellulose esters, polyethylene 
terephthalate, polycarbonate or other film-forming polymers. 
A relatively high pH-value (approximately 11 to 14) is adjusted by the 
alkaline processing mass in the photosensitive material, thus initiating 
development and imagewise dye diffusion. It has been found that the dyes 
and, hence, the images obtained are not particularly stable at this high 
pH-value. Accordingly, the material has to be made substantially neutral 
or weakly acid on completion of development. This can be done in known 
manner by providing the material with an additional, acid polymer layer 
which becomes accessible only gradually to the alkaline processing mass 
during development. In the context of the invention, an acid polymer layer 
is a binder layer containing polymeric compounds with acid groups, 
preferably sulpho or carboxyl groups. These acid groups react with the 
cations of the processing mass to form salts and, in doing so, reduce the 
pH-value of the mass. The polymeric compounds and, hence, the acid groups 
are of course incorporated in non-diffusible form in the above-mentioned 
layer. In many cases, the acid polymers are derivatives of cellulose or 
derivatives of polyvinyl compounds, although it is also possible to use 
other polymeric compounds. Examples of suitable acid polymers include 
cellulose derivatives with a free carboxyl group, for example cellulose 
dicarboxylic acid semiesters with a free carboxyl group, such as cellulose 
acetate hydrogen phthalate, cellulose acetate hydrogen glutarate, ethyl 
cellulose acetate hydrogen succinate, cellulose acetate hydrogen succinate 
hydrogen phthalate, ethers and esters of cellulose modified with further 
dicarboxylic acid anhydrides or with sulphonic acid anhydrides, for 
example with o-sulphobenzoic acid anhydride, carboxyl methyl cellulose, 
also polystyrene sulphonic acid, polyvinyl hydrogen phthalate, polyvinyl 
acetate hydrogen phthalate, polyacrylic acid, acetals of polyvinyl alcohol 
with aldehydes which are substituted by carboxy or sulpho groups, such as 
o-, m- or p-benzaldehyde sulphonic acid or carboxylic acid, partially 
esterified ethylene/maleic acid anhydride copolymers, partially esterified 
methyl vinyl ether/maleic acid anhydride copolymers and the like. 
The acid polymer layer must contain a sufficient quantity of acid groups to 
reduce the pH-value of the processing mass from its original level of 11 
to 14 to such an extent that, finally, the material is either 
substantially neutral or weakly acid (pH-value 5 to 8). 
The delay in pH-reduction is obtained in known manner by coating the acid 
polymer layer with a so-called retarding layer. This retarding layer is an 
alkali-permeable layer which preferably consists of a polymer inert to 
alkali, for example polyvinyl alcohol or a partially acetalised polyvinyl 
alcohol. The delay in pH-reduction may be adjusted as required by suitably 
selecting the thickness and composition of this retarding layer. A 
retarding layer containing polymers with novel permeability behaviour is 
described, for example, in German Patent Application P 24 55 762.8. 
Neutralisation systems, which are combinations of an acid polymer layer and 
a retarding layer, are described for example in DT-PS 1,285,310. Layer 
combinations of this kind may be present in the material according to the 
invention, for example in the photosensitive part between the transparent 
layer substrate and the image-receiving layer. Another possibility is to 
arrange the neutralisation system of an acid polymer layer and a retarding 
layer on the cover sheet. These two layers must of course be arranged in 
such an order that the alkali in the processing mass has first to 
penetrate through the retarding layer in order to reach the acid polymer 
layer. 
The dye diffusion transfer process according to the invention may be 
carried out advantageously in or by means of a suitable self-developer 
camera. This camera may be provided, for example, with devices by which it 
is possible, after exposure of the photosensitive element, to distribute a 
working solution between the photosensitive element and the cover sheet, 
and to mask the photosensitive material in such a way that it is 
impermeable to light from above. A camera of this kind is preferably 
provided with two squeezing rollers in contact with one another between 
which the one-sheet material is pulled out, thereby splitting open a 
laterally arranged container so that it releases its contents between the 
layers of the one-sheet material. 
Since, after passing through the squeezing rollers, the photosensitive 
element is protected on both sides against undesirable exposure by 
light-impermeable layers, the exposed material may be pulled out of the 
camera immediately after the beginning of development. 
For processing the one-sheet material after it has been exposed imagewise, 
the photosensitive element is brought into contact with the aqueous 
alkaline working solution. The silver halide emulsion layers exposed 
imagewise are developed in the presence of the developer compound, an 
imagewise distribution of oxidation products of the developer compound 
being obtained in consistency with the positive silver image formed. These 
oxidation products oxidise the associated colouring compound which 
releases the diffusible dye by reacting with the alkali of the activator. 
The aqueous alkaline working solution may contain viscosity-increasing 
additives, for example hydroxy ethyl cellulose. The working solution may 
also contain in known manner development accelerators, stabilisers, silver 
salt solvents, fogging agents, antioxidants and other additives. 
EXAMPLE 1 
A photosensitive element of a photographic material according to the 
invention was prepared by successively applying the following layers to a 
transparent substrate of polyester film. The quantities indicated are each 
based on 1 square meter. 
(1) A mordant layer consisting of 3.6 g of octadecyl trimethyl ammonium 
methyl sulphate and 9.0 g of gelatin, 
(2) A reflection layer of 48 g of TiO.sub.2 and 4.8 g of gelatin, 
(3) A gelatin intermediate layer of 2.6 g of gelatin, 
(4) A dye layer with silver sulphide grains of 1.25 g. of compound 
1(yellow) and 3.35 g of gelatin, 
(5) A silver bromide emulsion layer having incorporated therein a 
black-and-white developer and consisting of 0.95 g of AgBr, 1.2 g of 
octadecyl hydroquinone sulphonic acid, 0.36 g of octadecyl hydroquinone 
and 2.2 g of gelatin, and 
(6) A protective layer of 2.6 g of gelatin. 
After exposure through a stepped wedge, the photosensitive element was 
covered on the layer side with a polyester film. A splittable container 
with an alkaline working liquid of the following composition was used for 
developing the imagewise exposed photosensitive element: 
25 g of sodium hydroxide 
1 g of phenidone 
2 g of sodium thiosulphate 
4 g of sodium sulphite 
1 g of paraformaldehyde 
10 ml of benzyl alcohol 
30 g of Natrosol HHK 250 (hydroxy ethyl cellulose) made up with water to 
1000 ml. 
The image set was guided through a pair of squeezing rollers so that the 
developer paste was distributed between the photosensitive element and the 
cover sheet. The paste thickness was 140.mu.. In order to adjust the 
thickness of the paste, spacer strips of corresponding thickness were 
arranged laterally along the edge of the image between the photosensitive 
element and the cover sheet. After an exposure time of 10 minutes at 
20.degree. C., the image element was separated off and freed from the 
paste adhering to it. A positive yellow dye image of good colour quality 
was visible through the transparent substrate with the TiO.sub.2 -layer as 
image background. 
EXAMPLE 2 
The procedure was repeated as described in Example 1, except that, instead 
of layers (4) and (5), the following layers were applied: 
(4) A dye layer with silver sulphide grains of 0.83 g of compound 2 
(magenta) and 2.85 g of gelatin 
(5) A green-sensitised silver bromide emulsion layer of 0.67 g of AgBr, 
0.83 g of octadecyl hydroquinone sulphonic acid, 0.25 g of octadecyl 
hydroquinone and 1.5 g of gelatin. 
A positive magenta dye image was obtained after processing in the same way 
as in Example 1. Dmin 0.65; Dmax 1.62. 
EXAMPLE 3 
The procedure was repeated as described in Example 1, except that, instead 
of layers (4) and (5), the following layers were applied: 
(4) A dye layer with silver sulphide grains of 1.6 g of compound 3 (cyan) 
and 2.2 g of gelatin 
(5) A red-sensitised silver bromide emulsion layer of 1.65 g of AgBr, 1.2 g 
of octadecyl hydroquinone sulphonic acid, 0.35 g of octadecyl hydroquinone 
and 2.0 g of gelatin. 
A positive cyan dye image of good colour quality was obtained after 
processing in the same way as in Example 1. 
EXAMPLE 4 
The procedure was repeated as described in Example 2, except that compound 
2 in layer 4 was replaced by compounds 4, 5 and 9. Positive magenta dye 
images were obtained in each case after processing in the same way as in 
Example 1. 
EXAMPLE 5 
The photosensitive material described in Example 2, was developed in the 
same way as in Example 1, except that, instead of phenidone, the compounds 
identified below were used as auxiliary developers. They were each used in 
a quantity of 5 g per liter of paste. The following results were obtained: 
______________________________________ 
Auxiliary developer Dmin Dmax 
______________________________________ 
N-ethyl-N-hydroxy ethyl-p- 
phenylene diamine 0.55 1.31 
N-methyl aminophenol 0.45 1.67 
Pyrocatechol 0.49 1.58 
p-tolyl hydroquinone 0.77 1.56 
Piperidinohexose reductone 
monoacetate 0.53 1.56 
1-phenyl-4-methyl-4-hydroxy 
methyl-3-pyrazolidone 
0.51 1.67 
______________________________________ 
EXAMPLE 6 
The following layers were applied to the substrate described in Example 1 
(transparent substrate, layers 1, 2 and 3): 
(4) A dye layer with silver sulphide grains of 1.6 g of compound 8(cyan) 
and 2.2 g of gelatin, 
(5) A red-sensitised silver bromide emulsion layer of 1.57 g of AgBr, 1.12 
g of octadecyl hydroquinone sulphonic acid, 0.34 g of octadecyl 
hydroquinone and 1.95 g of gelatin, 
(6) A barrier layer of silver sulphide grains 1.0 g of octadecyl 
hydroquinone sulphonic acid and 4.0 g of gelatin, 
(7) A dye layer with silver sulphide grains of 0.94 g of compound 7 
(magenta) and 2.85 g of gelatin, 
(8) A green-sensitised silver bromide emulsion layer of 1.57 g of AgBr, 
1.12 g of octadecyl hydroquinone sulphonic acid, 0.34 g of octadecyl 
hydroquinone and 1.95 g of gelatin, 
(9) A barrier layer identical with layer (6), 
(10) A dye layer of 1.48 g of compound 6 (yellow) and 2.85 g of gelatin, 
(11) A silver bromide emulsion layer of 1.65 g of AgBr 1.2 g of octadecyl 
hydroquinone sulphonic acid, 0.35 g of octadecyl hydroquinone and 2.0 g of 
gelatin, and 
(12) A protective layer of 2.6 g of gelatin. 
A strip of the image element was exposed through a colour separation wedge 
and subsequently processed in the same way as described in Example 1. With 
a paste thickness of 260.mu., a direct-positive multicoloured reproduction 
of the original was obtained after a development time of 20 minutes. 
EXAMPLE 7 
The following layers were applied to the substrate described in Example 1 
(transparent substrate, layers 1, 2 and 3): 
(4) A dye layer of 1.25 g of compound 1 (yellow) and 1.35 g of gelatin, 
(5) A blue-sensitised emulsion layer with an unfogged direct-positive 
silver chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8 g, 
and 
(6) A protective layer of 2.6 g of gelatin. 
A strip of the photosensitive element was exposed and subsequently 
developed in conjunction with a paste bag, a cover sheet and two laterally 
arranged spacer strips, in the same way as described in Example 1. The 
spacer strips had a thickness of 180.mu.. A paste of the following 
composition was used as developer: 
25 g of potassium hydroxide 
5 g of N,N,N',N'-tetramethyl-p-phenylene diamine 
1 g of acetyl phenyl hydrazine 
1 g of paraformaldehyde 
0.1 g of benzotriazole 
10 ml of benzyl alcohol 
35 g of Natrosol HHR 250 (hydroxy ethyl cellulose) made up with water to 
1000 ml. 
A positive yellow dye image of good colour quality was obtained after a 
development time of 10 minutes. 
EXAMPLE 8 
The procedure was repeated as described in Example 7, except that, instead 
of layers (4) and (5), the following layers were applied: 
(4) A dye layer of 0.83 g of compound 2 magenta and 1.85 g of gelatin, and 
(5) A green-sensitised emulsion layer with an unfogged direct-positive 
silver chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8 g. 
A positive magenta dye image was obtained after processing in the same way 
as in Example 7. Dmin 0.38, Dmax 1.24. 
EXAMPLE 9 
The procedure was repeated as described in Example 7, except that, instead 
of layers (4) and (5), the following layers were applied: 
(4) A dye layer of 1.6 g of compound 3 (cyan) and 1.2 g of gelatin, and 
(5) A red-sensitised emulsion layer with an unfogged direct-positive silver 
chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8 g. 
A positive cyan dye image was obtained after processing in the same way as 
in Example 7. 
EXAMPLE 10 
The procedure was repeated as described in Example 8, except that the 
compound in layer 4 was replaced by compounds 4, 5 and 9. Positive magenta 
dye images were obtained in each case after processing in the same way as 
in Example 7. 
EXAMPLE 11 
The following layers were applied to the substrate described in Example 1 
(transparent substrate, layers 1, 2 and 3): 
(4) A dye layer of 1.6 g of compound 8 (cyan) and 2.2 g of gelatin, 
(5) A red-sensitised emulsion layer with an unfogged direct-positive silver 
chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8, g 
(6) A barrier layer of 0.26 g of octadecyl hydroquinone sulphonic acid and 
2.26 g of gelatin, 
(7) A dye layer of 0.94 g of compound 7 magenta and 2.85 g of gelatin, 
(8) A green-sensitised emulsion layer with an unfogged direct-positive 
silver chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8, g 
(9) A barrier layer identical with layer (6), 
(10) A dye layer of 1.48 g of compound 6 (yellow) and 2.85 g of gelatin, 
(11) A blue-sensitised emulsion layer with an unfogged direct-positive 
silver chloride bromide emulsion, silver covering 2.0 g, gelatin 1.8 g, 
and 
(12) A protective layer of 2.6 g of gelatin. 
A strip of the image element was exposed through a colour separation wedge 
and subsequently processed in the same way as described in Example 7. With 
a paste thickness of 260.mu., a direct-positive multicoloured reproduction 
of the original was obtained after a development time of 20 minutes. 
EXAMPLE 12 
The following layers were applied to the substrate described in Example 1 
(transparent substrate, layers 1, 2 and 3): 
(4) A dye layer with 0.83 g of compound 2 (magenta) and 2.8 g of gelatin, 
(5) A silver bromide emulsion layer of 1.6 g of AgBr and 2.0 g of gelatin, 
and 
(6) A protective layer of 2.6 g of gelatin. 
The material was exposed and processed in the same way as described in 
Example 1. A paste of the following composition was used as developer: 
25 g of sodium hydroxide 
10 ml of benzyl alcohol 
1 g of paraformaldehyde 
0.1 g of benzotriazole 
0.25 g of ascorbic acid 
5 g of N,N,N',N'-tetramethyl-p-phenylene diamine 
35 g of Natrosol HHR 250 made up with water to 1 liter. 
With a paste thickness of 180.mu., a magenta-coloured negative reproduction 
of the original was obtained after a development time of 10 minutes.