Dye toning system

Disclosed herein is a system for selectively mordanting a dye to preselected areas of a black and white photographic silver image and rapidly removing all traces of the dye from the non-image areas. The system includes novel processing compositions to enable the entire process to be carried out rapidly with a minimum amount of equipment.

This invention relates to a dye toning system. More specifically, the 
invention deals with an integrated system for rapidly mordanting and 
dyeing preselected areas of a photographic silver image and removing all 
traces of the dye from the non-image areas. 
The process of dye toning has been known in the photographic arts for many 
years. In general, dye toning is accomplished by transforming the silver 
of a photographic image into a variety of other insoluble stable compounds 
which have the property of uniting with various dyes. The unification of 
the dye with the insoluble compounds is commonly termed mordanting and has 
been used as the basis of dye toning systems for many years. Prior art 
mordanting systems are fairly complex operations, requiring extensive 
laboratory equipment and lengthy processing periods. A typical prior art 
system for dyeing photographic silver images required a multistep 
processing operation. First, the entire image bearing colloid layer would 
be bleached with a ferricyanide solution to form a silver complex. In 
general, these mordanting solutions were fairly acidic and also stained 
the non-image background area. Accordingly, the bleaching treatment was 
generally followed by extended immersion in a water rinse or similar 
clearing solution to remove the stain from the non-image background. 
Thereafter, the entire image area was bathed with a separate acidified dye 
solution to form a dyed mordant with the existing ferricyanide complex. 
The acidified dye solution would also stain the background (non-image) 
areas. Accordingly, the dyeing step was generally followed by a second 
extended rinsing operation to clear residual dye stains from the 
non-imaged area and in some instances a further acidic treatment followed 
again by washing. 
In another prior art system for dye toning, the photographic silver image 
was converted into a halide or ferricyanide and then subsequently 
reconverted into another metal, e.g., copper, iron, uranium, by treatment 
with a complexing metal solution. Thus, the complex metal would replace 
the silver in the photographic image and serve as a mordant for a 
subsequent dye treatment. 
Both of the preceding processes involve the use of an acidic constituent, 
either as part of the mordanting or dyeing solutions. As the photographic 
silver images to be treated were generally dispersed in gelatin or an 
equivalent hardenable hydrophilic colloid material, this often resulted in 
tenacious stains adhering to the non-image areas. Hence, the prior art 
systems tended to require extensive cleansing operations be undertaken 
following the dyeing procedure in an effort to remove these dye stains 
from the non-image areas. Use of these systems required a considerable 
amount of photographic equipment. 
A further drawback to prior art dye-toning procedures was that they were 
relatively lengthy procedures. Thus, it might take an hour or more to dye 
a single photographic image. 
As a consequence of the lengthy processing times, extensive equipment 
requirements, stain removal difficulties and the high cost, dye toning was 
largely abandoned by the photographic art in favor of in-situ photographic 
coloring systems. Nonetheless, dye toning remained an important tool for 
applying coloration to black and white photographic silver images. Over 
the past 20 years photographic silver image dye-toning operations have 
been largely confined to academic and industrial institutions which could 
afford to bear the expense of equipping and operating a laboratory for 
such systems. 
The present invention provides a rapid system for dye toning photographic 
silver images requiring a minimum of equipment and instruction. Further 
advantages of the present system are the ability to produce dye-toned 
photographic silver images free from background staining and the ease and 
thoroughness with which excess dye solution may be removed from the 
non-image areas. Briefly summarized, the invention provides a method for 
dyeing preselected areas of a photographic silver image by contacting such 
areas with an aqueous dye-mordant solution having a pH of at least 7.5 for 
a predetermined time period and removing the dye from the non-image area 
with an aqueous alkaline solution having a pH of at least 7.5. Since the 
entire dyeing operation is carried out in the absence of acidic solutions 
there is little or no propensity to the formation of stain and the system 
repeatably yields brilliant dye images of high quality. The system is 
especially useful in dyeing photographic images obtained by means of black 
and white silver salt diffusion transfer reproduction although it may be 
employed to color both negative and positive photographic silver images 
embedded in hydrophilic carrier mediums and free from agents which might 
have a mordanting action toward the coloring dyes or harden the colloid. 
Accordingly, one object of the present invention is to provide a rapid 
system for dye toning, black and white, positive and negative photographic 
silver images. 
Another object of the present invention is to provide a simplified 
dye-toning system for photographic silver images requiring a minimum of 
equipment for operation. 
A still further object of the present invention is to provide a dye-toning 
system in which dye stains may be removed from the background and 
non-image areas quickly and thoroughly. 
Another aspect of the present invention is to provide a dye-toning system 
for photographic silver images in which the background (non-image) areas 
are rapidly freed from staining after the dyeing operation has been 
completed. 
These and other objects of the present invention will be apparent upon 
consideration of the following detailed description. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention is primarily concerned with the application of dyes 
to preselected areas of photographic silver images. Suitable photographic 
silver images for use in the invention are those generated by imagewise 
exposure of photographic silver halides embedded in colloid layers to 
actinic radiation. The silver halide layers can be any of the conventional 
negative or positive type developing emulsions. Typical silver halides 
include silver chloride, silver bromide, silver bromoiodide, silver 
chloroiodide, silver chlorobromoiodide and the like. Mixtures of more than 
one of the preceding silver halides may be employed and in accordance with 
the general practice such emulsions can contain spectral sensitizers, 
anti-fogging agents and similar ingredients. The photosensitive layers 
and/or image receiving layers may rest on those supports generally 
employed for photographic elements including, for example, paper, films of 
cellulose nitrate, cellulose ester, polystyrene, polyesters, polyethylene 
terephthalate and papers coated with resinous materials as, for example, 
with alpha-olefin polymers containing 2-4 carbon atoms as exemplified by 
polyethylene, polypropylene, ethylene-butene copolymers or the like as 
well as glass, metal plates or foils and similar photographic supports. 
The photographic silver halide constituent may be dispersed in natural or 
synthetic hydrophilic colloid binding materials generally employed for 
this purpose including, for example, gelatin, colloidal albumen, water 
soluble vinyl polymers, cellulose derivatives, acrylamide polymers, 
polyvinyl pyrrolidone and similar agents known in the art. A particularly 
preferred photographic silver image is obtained by means of a diffusion 
transfer reproduction process of the type in which an exposed silver 
halide emulsion is developed in the presence of a silver halide solvent 
such as sodium thiosulfate in contact with a receiving sheet with the 
result that a silver image is developed in the emulsion layer and 
thereafter the residual silver halide is dissolved by the silver solvent 
and transferred image-wise by diffusion to a receiving sheet where it is 
transformed to metallic silver or other silver compound of high optical 
density. The preceding processes have been described at length in the 
patent (e.g. Rott U.S. Pat. No. 2,352,014) and periodical literature and 
are well-known in the art. 
The photographic silver images which are the starting point of the present 
invention are obtained as the result of image-wise exposure and 
development whereby the photographic silver halide products are converted 
to metallic silver images. Preferably, the colloid binder in which the 
photographic silver image is embedded should be free of any agent which 
might act as a mordant for the coloring dyes employed in the present 
invention. To this end, multivalent inorganic salts including those of 
aluminum, chromium, titanium, iron, vanadium and zirconium; gall compounds 
and other organic agents which harden colloid (e.g. gelatin) layers such 
as tannins (e.g., tannic acid), oxazolidines, dialdehyde starches and 
similar agents are preferably absent from the image-bearing colloid layer 
since the presence of these constituents can impart a mordanting quality 
to the colloid layer thereby resulting in the non-image areas becoming 
stained with the dye. 
According to the method of the present invention a negative or positive 
black and white photographic silver image is prepared for the instant 
process by thoroughly washing the photographic silver image with water. 
The washing operation can be carried out by vigorously spraying cold water 
across the face of the photographic image for approximately 30 seconds to 
1 minute. 
In the event that a particular silver image was not adequately processed 
during photographic development to remove all traces of the photographic 
processing fluids (e.g. developers and/or fixer materials) from the 
finished image, the image may be prepared for dyeing by treatment with an 
alkaline preparation solution having a pH above 7.5. The preparation 
solution is an alkaline aqueous co-solvent mixture having a pH above 7.5 
and preferably in the range pH 7.5 to 11.5. Suitable alkaline constituents 
for use in the preparation solution are those water soluble inorganic and 
organic alkaline agents which do not react adversely on photographic 
silver images, and include by way of non-limiting example, alkali metal 
sulfites such as sodium sulfite and potassium sulfite, alkali metal salts 
of erythorbic acid (e.g. sodium erythorbate) alkali metal carbonates such 
as sodium, potassium and lithium carbonate, alkali metal hydroxides, e.g. 
sodium hydroxide, potassium hydroxide, organic amines including guanidine 
carbonate, monoethanolamine, diethanolamine, and similar straight and 
branched chain alkanol amines having from 1 to 4 carbon atoms in the 
hydrocarbon chain. Also useful are alkaline ammonium compounds including 
by way of non-limiting example ammonium hydroxide, ammonium sulfite, 
ammonium carbonate, the ammonium salts of weak organic and inorganic 
acids, e.g. ammonium citrate, ammonium malonate; heterocyclic alkaline 
compounds including morpholines and their lower alkyl (C.sub.1 -C.sub.4) 
and lower hydroxyalkyl (C.sub.1 -C.sub.4) derivatives e.g. N-hydroxyethyl 
morpholines; piperidines including their lower alkyl (C.sub.1 -C.sub.4) 
and lower hydroxyalkyl (C.sub.1 -C.sub.4) derivatives. The alkaline moiety 
helps free the silver image and the colloid in which the image is embedded 
from the action of any materials which may yield dye mordanting 
contaminants and which may not have been removed in the course of 
developing the photographic silver halide image. Mordanting contaminants 
are those organic and inorganic agents such as oxidized developing agents, 
e.g. quinone and the like which may act as dye mordants in the non-image 
areas thereby imparting a background stain to the photographic image. 
Optional ingredients for the preparation solution can include surface 
active agents (surfactants) including anionic, non-ionic, and cationic 
compositions. Specific anionic surfactants found to be useful include the 
sulfated or sulfonated ethers of long and short chain aliphatic groups 
(e.g.: C.sub.17 H.sub.33 --O--C.sub.2 H.sub.4 --SO.sub.3 --N.sub.a), or 
(C.sub.17 H.sub.33 --O--C.sub.2 H.sub.4 --O--SO.sub.3 --N.sub.a) 
sulfonated alkyl esters of long chain fatty acids 
##STR1## 
sulfonated glycol esters of long chain fatty acids 
##STR2## 
sulfonated alkyl substituted amides of long chain fatty acids (e.g. 
##STR3## 
alkylated aryl sulfonates (dodecyl benzene sodium sulfonate), hydro 
aromatic sulfonates (tetrahydronaphthalene sodium sulfonate), and alkyl 
sulfosuccinates (dioctyl sodium sulfosuccinate) alkyl sulfonates (e.g., 
dodecyl sodium sulfonate) alkyl sulfonates (e.g., dodecyl sodium 
sulfonate) alkyl sulfates (sodium olyel sulfate), and soaps such as sodium 
laurate, ammonium stearate and diethanol-ammonium oleate. Non-ionic 
surface active agents useful in the invention include monoethers of 
polyglycol with long chain fatty alcohols such as the reaction products of 
ethylene oxide or polyethylene glycol with long chain fatty alcohols, 
monoesters of polyglycols with long chain fatty acids including reaction 
products of ethylene oxide or polyethylene glycol with long chain fatty 
acids, partial esters of polyhydric alcohols with long chain 
monocarboxylic acids (glycerol monostearate, sorbitan trioleate), and 
partial and complete esters of long chain monocarboxylic fatty (and/or 
resinous) acids with polyglycol ethers or polyhydric alcohols (e.g., 
tristearate acid ester of polyglycol ether of sorbitan). Cationic 
surfactants useful in the present invention include quaternary ammonium 
salts in which one of the groups attached to the nitrogen has an aliphatic 
group having 8 or less carbon atoms (e.g., trimethyl acetyl ammonium 
halide. Especially preferred surfactants are dioctyl sodium sulfosuccinate 
(available from American Cyanamid Inc. as Aerosol OT and Aerosol OS) 
Saponin (C.sub.32 H.sub.54 O.sub.18) and Tergitol NPX (alkyl aryl 
polyethylene glycols) (available from the Union Carbide Corporation). In 
many instances it is also desirable to include a rheological additive or 
thickener in the preparation solution to impart improved viscosity to the 
solution. For this purpose, polyethylene glycols (e.g., Carbowax 400 
available from Union Carbide Corporation), polyvinyl pyrrolidone 
(available from General Aniline and Film Corporation) Avg. MW 
40,000-160,000, and carboxymethyl cellulose may be employed. 
Organic solvents, preferably those which are wholly or partly miscible with 
water, including normal and branched chain alkyl alcohols containing from 
2-4 carbon atoms (e.g., ethyl, isopropyl alcohols), ketonic alcohols 
(e.g., diacetone alcohol), ether alcohols (e.g., monoethyl ether of 
diethylene glycol, methoxyethanol, cycic alcohols (e.g., 
tetrahydrofurfuryl alcohol), dioxane and, ketones, (e.g., acetone, 
methylethyl ketone), and heterocyclic solvents including morpholine, 
formyl piperdine), and lactams, (e.g., butyrolactone and pyrrolidones) are 
employed as adjuvants in the preparation solution of the present 
invention. The relative proportions of the constituents in the aqueous 
preparation solution is not critical provided the final preparation is an 
aqueous solution of flowable liquid having a pH above 7.5 and preferably 
in the range 7.5 through 11.5. Illustrative examples of preparation 
solutions which may be used in the present invention including the 
preferred formulation are presented in Table A. 
TABLE A 
______________________________________ 
I SODIUM SULFITE 5 to 10 g. 
ISOPROPYL ALCOHOL 150 to 350 ml. 
SODIUM HYDROXIDE 0.5 to 2.0 g 
SURFACE ACTIVE AGENT 
5% SAPONIN 5 ml. 
WATER to make 1000 ml. 
II POLYVINYL PYROLIDONE 15 G. 
ETHYL ALCOHOL 200 ml. 
SODIUM SULFITE 7.0 G. 
GUANIDINE CARBONATE 10.0 G. 
WATER to make 1000 ml. 
III POLYVINYL PYRROLIDONE 35 G. 
WATER 600 ml. 
GUANIDINE CARBONATE 8 G. 
SODIUM SULFITE 8 G. 
Water to make 1000 ml. 
IV ETHYL ALCOHOL 50 to 150 ml. 
ISOPROPYL ALCOHOL 100 to 300 ml. 
SODIUM SULFITE 5 to 15 G. 
GUANIDINE CARBONATE 5 to 15 G. 
Water to make 1000 ml. 
______________________________________ 
The substrate bearing the silver image to be colored is flooded with or 
immersed in the preparation solution for a period of from about 30 seconds 
to 2 minutes at ambient (room) temperature. This time period is sufficient 
to desensitize any remaining mordanting contaminants and to deactivate any 
dye mordanting constituents which may have remained affixed to the silver 
image or in the colloid. The preparation solution is then removed by 
blotting with paper toweling, a cotton swab, Q-tip, sponge or other 
absorbent material. 
Following either a thorough water washing and/or the preparation bath 
treatment, the photographic silver image is ready for the dyeing 
operation. In order to facilitate further consideration of the invention, 
the present system will be described with respect to dyeing preselected 
portions of a photographic silver image produced on a coated paper base 
with a diffusion transfer reproduction process as described in U.S. Pat. 
No. 2,751,300 Example 2 although it should be clearly understood that the 
invention is not limited to use in this fashion. Specifically, the 
invention will be described with respect to dyeing preselected area of a 
photographic silver image depicting the word "RECOGNITION" in block 
letters. 
An important advantage of the instant system is that the dyeing and 
mordanting operations are carried on simultaneously by application to the 
image bearing substrate of a single processing solution. The coloring bath 
which is used to dye the photographic silver image is mixed just prior to 
use by admixing predetermined quantities of a dye bath and a mordanting 
solution. The dyeing operation is carried on by forming a mordanting 
complex from the metallic silver of the photographic image and one or more 
complexing agents carried in the coloring bath. The mordanting complex has 
an affinity for the dye present in the coloring bath. 
The mordanting solution consists essentially of an aqueous alkaline 
solution of one or more complexing agents which will form an insoluble 
stable salt complex with the metallic silver of the photographic image. 
Suitable complexing agents are water soluble compounds which function as 
oxidizing agents under aqueous alkaline conditions such as alkali metal 
ferricyanides (e.g. potassium ferricyanide). The foregoing oxidizing 
agents may optionally be used in conjunction with complexing adjuvants, 
e.g. sodium thiocyanate, water soluble halogens (e.g. iodine, chlorine or 
bromine), alkali metal salts of near neutral pH (pH 6.5-7.5), including 
halogen salts, e.g. chlorides (sodium chloride), bromides, iodides 
(potassium iodide), sulfate (e.g. potassium sulfate), or nitrates (e.g. 
sodium nitrate) either singly or together with each other and which will, 
together with the oxidizing agent, form a complex with the silver image. 
The complex oxidizing agents are generally present in the form of their 
alkali metal salts, preferably the sodium, potassium or lithium salts, 
potassium ferricyanide being the preferred complexing and oxidizing agent 
for use in the invention. In most instances, the mordanting solution will 
contain from about 8 to about 20% and preferably from about 10 to about 
15% by weight of the complexing agent. In addition to the complexing 
agent, the mordanting solution will also preferably contain from about 0.1 
to about 5% by weight of iodine. The iodine can be added to the aqueous 
mordanting solution either as an alkali metal iodide salt (preferably 
potassium iodide) which is oxidized to elemental iodine by the 
ferricyanide in one embodiment of the invention, or preferably in the form 
of an elemental iodine solution in an aqueous or organic solvent miscible 
with water (e.g., iodine in acetone). Although the iodine can be added to 
the aqueous solution in the form of potassium iodide, any soluble, 
colorless, alkali metal iodide salt may be employed in the invention. 
The mordanting solution also contains an alkaline material to bring the 
solution to a pH above 7.5 and preferably in the range pH 7.5 to 11.5. In 
the preferred embodiment of the invention, the mordanting solution 
contains excess alkaline material in the event that the dye bath may be 
carrying a small quantity of acidic reactant. Since most dyes are 
commercially available in the form of their acid salts, the excess alkali 
in the mordanting solution insures that the final processing bath used to 
color the photographic silver image is within the alkaline pH range in 
which the present invention will operate. The water soluble organic and 
inorganic alkaline constituents of the mordanting solution may be selected 
from amongst those employed in formulating the preparation solution. 
Laboratory trials consistently show that operation of the invention above 
pH 11.5 and below pH 7.5 does not provide satisfactory dyeing conditions. 
Optionally, a rheological control agent or thickener of the type employed 
in conjunction with the preparation solution may also be utilized in the 
mordant solution. 
It has been found that the alkaline nature of the mordanting solution will 
bring dyes present in the dye bath into alkaline conditions and maintain 
them in their soluble form as opposed to the flocculated precipitate which 
often occurs when dyes are removed from an acid environment. 
The rheological control agent assists in maintaining the combined 
mordanting-dye solution which is applied to the photographic silver image 
in stable condition for several hours by preventing flocculation of the 
dye and its precipitation from the solution. The level of iodine in the 
mordanting solution is intentionally kept low because iodine stains 
gelatin and many hydrophilic colloids. The instant process does not 
require the presence of a relatively high level of iodine in the 
mordanting solution, as a stable complex is formed with the elemental 
silver of the photographic image and the complexing agent of the 
invention. Accordingly, approximately from about 0.1 to 5% of iodine is 
required in the mordanting solution. The preparation of the mordanting 
solution is accomplished by combining the complexing agent, iodine and 
optical constituents in the desired quantities with a sufficient amount of 
water to bring them into solution and within the range pH 7.5 to 11.5. 
Several suitable mordanting solutions including the preferred formulation 
with polyvinyl pyrrolidone are illustrated in Table B. 
TABLE B 
______________________________________ 
I POTASSIUM FERRICYONIDE 90 to 150 G. 
POTASSIUM IODIDE 0.1 to 4.5 G. 
POTASSIUM CARBONATE 5 to 10 G. 
WATER TO MAKE 1000 ml. 
II POTASSIUM FERRICYANIDE 90 to 150 G. 
3% IODINE SOLUTION IN ACETONE 
75 to 150 ml. 
POTASSIUM CARBONATE 5 to 10 G. 
WATER TO MAKE 1000 ml. 
III POTASSIUM FERRICYANIDE 90 to 150 G. 
3% IODINE IN ACETONE 75 to 150 ml. 
GUANIDINE CARBONATE 5 to 19 G. 
WATER TO MAKE 1000 ml. 
IV PREFERRED 
POLYVINYL PYROLIDONE 35 G. 
POTASSIUM FERRICYANIDE 124 G. 
3% IODINE SOLUTION IN ACETONE 
100 ml. 
GUANIDINE CARBONATE 10 G. 
WATER TO MAKE 1000 ml. 
______________________________________ 
The mordanting solution is prepared in advance and held separately until 
just prior to admixture with the dye bath. 
The dyes which may be used in the present invention are those dispersible 
in aqueous and organic solvents and include those generally classified as 
basic dyes as well as those acid dyes free from sulfonic groups and which 
have an affinity for the mordanting complex of this invention. Diazo dyes 
containing only the carboxylic group as the acidulating factor may be 
employed in the invention. In addition, the dyes must be capable of being 
mordanted under the alkaline conditions of the invention and remain 
insoluble in the mordanted condition. It will be appreciated that since 
the mordanting and dying reactions are taking place simultaneously in the 
same solution, only those dyes which can be mordanted under alkaline 
conditions may be employed successfully in the present invention. A 
non-limiting example of the dyes which may be employed in preparing the 
dye baths of the present invention is found in Table C. 
TABLE C 
__________________________________________________________________________ 
BASIC DYES 
GENERIC TRADE SPECIFIC 
STRUCTURES NAME IDENTIFICATION COLOR 
__________________________________________________________________________ 
DIPHENYMNENTHANE AURAMINE YELLOW 
CI 41000 
TRIPHENYLMETHANE 
BASIC MALACHITE GREEN 
GREEN # 4 
GREEN 
CI 42000 
BASIC VICTORIA BLUE 
BLUE # 11 
BLUE R 
CI 44040 
BASIC METHYL VIOLET 
VIOLET # 1 
VIOLET 2B 
CI 42535 
BASIC BASIC RED 
RED # 9 FUCHSIN 
CI 42500 
ROSANILINE RED 
CI 42510 
ACRIDINE ACRIDINE YELLOW 
YELLOW 
CI 46025 
OXAZINE BASIC NILE BLUE A BLUISH 
BLUE # 12 
CI 51180 
THIAZINE BASIC THIOFLAVINE T YELLOW 
YELLOW CI 49005 
TOLUIDINE BLUE BLUE 
CI 52040 
BASIC METHYLENE BLUE BLUE 
BLUE # 9 CI 52015 
AZINE BASIC SAFRANINE O RED 
RED # 2 CI 50240 
DIAZO CHRYSOIDINE 
MONO-DIAZO COUPLED DYE 
YELLOW 
Y CI 11270 
ACID DYES 
RHODANINE RHODAMINE BX SCARLET 
PATENT BLUE A GR BLUE 
DIAZO METHYL RED YELLOW 
__________________________________________________________________________ 
In addition to the dyes which are generally present at a level of from 
about 0.001% to 1%, the dye baths may also contain one or more organic 
solvents for the dye which are miscible with water and one of the 
rheological additives utilized in the preparation solution. 
The particular solvents used in the dye bath depend upon the nature of the 
dyes in the bath, and diphenyl and triphenyl methane dyes generally being 
soluble in lower alcohols such as methanol. The organic solvents which may 
be used in the dye bath are preferably water miscible and must be at least 
partially water miscible. 1-formyl piperdine has been found to be 
especially useful as a dye solvent in the present invention. Generally, 
the solvents indicated to be useful in conjunction with the Preparation 
solution may be employed in formulating the dye baths of this invention. 
Preferably, the dye bath solution will contain from about 0.005% to about 
1.0% dye. The quantity of dye in a particular solution is varied according 
to the tinctatorial strength of the particular commercial dye batch from 
which the bath is being prepared and according to the color intensity 
desired by the operator on the finished image. The dye bath may optionally 
contain from about 5 to about 25% of an organic solvent which is at least 
partially water miscible and from about 1 to about 10% by weight of a 
rheological additive or surfactant which may be selected from amongst 
those employed in formulating the Preparation solution. The amount of 
organic solvent used in preparing a dye bath will vary from one dye to 
another. This is believed to be attributable to the manner in which 
different batches of the same dye are prepared by commercial 
manufacturers. Accordingly, to facilitate removal of a particular dye 
stain from the background (non-image) area it is often necessary to 
utilize increased levels of solvent or mixtures of the solvents mentioned 
in the invention. For example, the tendency of malachite green dyes to 
form tenacious stains is overcome by employing up to 30% by weight of 
isopropyl alcohol in preparing a bath containing this dye. The particular 
solvent to be added to a given dye bath may be selected by the operator 
from amongst the solvents enumerated herein in connection with the 
preparation bath. Rheological agents and surfactants selected from amongst 
those employed in the Preparation solution may also be employed in the dye 
bath. The dye baths of the invention are mixed in advance and held in 
separate containers for admixture with the mordanting solution just prior 
to use in the process of the invention. Several typical dye baths are 
illustrated in Table D. 
TABLE D 
______________________________________ 
I PREFERRED 
WATER 600 ml. 
POLYVINYL PYROLIDONE 
25 G. 
DIACETONE ALCOHOL 60 ml. 
1-FORMYL PIPERIDINE 65 ml. 
DYE ACCORDING TO 0.005 to 1.0% BY WT. 
TINCTATORIAL STRENGTH 
WATER TO MAKE UP TO 1000 ml. 
II "CARBOWAX" 4000 8 to 20 G. 
WATER 600 ml. 
ISOPROPYL ALCOHOL to 35% 
DIACETONE ALCOHOL to 15% 
DYE ACCORDING TO 0.005 to 1.0% BY WT. 
TINCTATORIAL STRENGTH 
WATER TO MAKE 1000 ml. 
III METHYL CELLUSOLVE 15 ml. 
ISOPROPYL ALCOHOL 150 ml. 
DYE ACCORDING TO 0.005% to 1.0% By Wt. 
TINCTATORIAL 
STRENGTH 
WATER TO MAKE 1000 ml. 
______________________________________ 
A further advantage of the processes and compositions of this invention is 
that they provide the operator with the ability to admix various dyes at 
the time of their application to the photographic image in order to obtain 
specific coloration effects in the finished product. In addition, it is 
possible by the present invention to vary the intensity of a particular 
dye to some extent by using the mordanting solution as a diluent for a 
specific dye bath. Thus, the invention affords complete coloring 
flexibility to the operator and enables this freedom of operation to be 
practiced at the time of applying the dye to the photographic image. This 
in turn permits easy adjustment of coloration and the concommitant 
availability of a wide range of color tones and hues from a fundamental 
group of dye colors. 
Just prior to use in dyeing a photographic silver image, approximately 
equal amounts of the mordanting solution and a particular dye bath are 
admixed together in a small container. It will be appreciated by those 
skilled in the art that the concentration of either the mordanting 
solution or the respective dye baths to be employed in the invention may 
be adjusted at the time of its preparation in order to permit the operator 
to employ equal amounts of each in preparing the processing solution which 
is to be applied to color the photographic silver image. However, the 
combined dye-mordanting solution must have a pH of at least 7.5 and 
preferably in the range pH 7.5-11.5. To accomplish this objective, it may 
be necessary to admix an excess quantity of the mordant solution with the 
dye bath in those instances where the dye both is somewhat acidic in 
nature. Accordingly it should be understood that the pH of the combined 
dye-mordant solution can be adjusted to fall within the proper alkaline 
range by regulating the quantity of mordanting solution which is added to 
a particular dye bath. Thus, a separate color processing solution will be 
prepared for each dye color which is to be applied to the image by 
combining appropriate quantities of dye bath and mordanting solution. This 
permits an operator to color one segment of a photograpahic image (e.g., 
the letters "REC" in the word RECOGNITION) in a first color and another 
portion of the same word (e.g., the letters "OGNI") in a second color. It 
will be appreciated that each dye bath is preferably prepared beforehand 
so that it may be combined with approximately equal volumes of the 
mordanting solution prepared for use in the invention. In such case the 
operator can combine equal volumes (e.g., a few milliliters) of mordanting 
solution and dye bath in the first color (e.g., yellow) in a separate 
container. The contents are admixed to form the combined color processing 
solution which is applied to preselected portions of the photograph, for 
example to color the garments on the arms and legs of a figure shown in 
the image. Application of the coloring solution (or any of the other 
processing fluids of the invention) can be by way of a Q-tip, sponge, 
cotton ball, paint brush or similar implement which will permit the 
operator to generously bathe the desired image area with the color 
processing solution. In the event the area to be dyed with the first color 
is adjacent to other silver image areas which are to be treated with 
different dye colors, the latter areas of the photographic image may be 
masked off using artists' drafting tape, a Mylar shield, or similar fluid 
impervious masking materials. The admixture of the dye bath and mordanting 
solution to form the color processing solution can be made in a small 
paper cup, glass beaker, or even on a water color palette of the type 
employed by artists. The quantity of processing fluid prepared is based on 
the size of the photogrpahic image area to be dyed, although in most 
instances from about five to about twenty ml. is sufficient. The premixed 
processing fluid can be generously applied to the image lines and areas 
which are to be colored and no care need be taken to prevent the fluid 
from spilling over onto the background areas of the photographic print, 
e.g., those portions which do not bear a silver image. Generally, the 
premixed coloring fluid is allowed to remain on the image area for a 
period of about a minute or so during which time the excess fluid is 
gently swabbed or agitated back and forth across the areas to be processed 
using the same implement previously employed to apply the solution to the 
image area. This agitation technique aids in insuring that a uniform 
coloration is imparted to the preselected image area. After the image has 
been immersed for about a minute or so, the excess fluid is removed by 
blotting with paper toweling, cotton or cloth wads, a sponge, or similar 
absorbent, non-abrasive material. 
At this point, a fixing solution is generously applied to the previously 
treated area in which the silver images no longer appear black, but 
instead bear the coloration imparted by the color processing solution. The 
fixing bath which is applied to those areas of the substrate treated with 
color processing fluid is an aqueous alkaline solution containing from 10 
to about 50% and preferably 20-40% of an organic solvent which is at least 
partially water soluble, and having a pH above 7.5 and preferably in the 
range pH 7.5 to 11.5. Suitable fixer solutions are substantially identical 
to the alkaline solution first applied to prepare the image to receive dye 
coloration and may contain the same constituents except that the fixer 
solutions must include 10-50% of an organic solvent which is at least 
partially water miscible, and preferably include from about 0.5 to 5% of a 
colorless alkali metal iodide to assist in stabilizing the mordanted dye 
complex. The presence in the fixer bath of the alkali metal iodide, 
preferably potassium iodide, also serves to brighten the mordanted dyes 
and to render them more transparent. Achieving a light transmitting 
mordanted dye is of great importance in those instances where the dyed 
photographic image is to be used as a transparency to be illuminated with 
an overhead projector or similar projection device. The preferred fixer 
solution of the invention includes an inorganic alkali metal salt of a 
reducing agent, and is preferably one containing a sulfite ion (e.g., 
sodium or potassium sulfite) as one alkaline constituent of the fixer 
solution. As in the case of the Preparation, mordanting, and dye baths of 
the invention, the relative proportion of ingredients in the fixer 
solution to one another is not critical except that the solution should 
comprise from about 0.5 to about 5% by weight of the iodide constituent, 
must contain from about 10 to about 50% by weight of a hydrocarbon solvent 
which is at least partially water miscible and must have a pH no lower 
than 7.5 and preferably in the range pH 7.5 - pH 11.5. Application of the 
alkaline fixer solution is made to the image areas which are generally 
still moist from the previous dyeing solution. The iodide constituent of 
the fixer is believed to form a complex with the dyed mordant thereby 
rendering it more transparent and intense. The fixer solution also acts to 
solubilize any unmordanted dye and bring it into solution. Accordingly, 
the fixer solution simultaneously renders the dye mordanted portions of 
the image more transparent and creates an alkaline condition which will 
assist in rapidly removing dyes from the background or non-image sites on 
the photographic substrate. It is important that the fixer solution 
maintain the alkaline condition imposed throughout the earlier steps in 
the dyeing procedure and accordingly the fixer solution has a pH of at 
least 7.5 and preferably in the range 7.5 through 11.5. 
Table E contains several non-limiting examples illustrating fixer solutions 
which may be employed in practicing the process of the present invention. 
TABLE E 
______________________________________ 
I (PREFERRED) 
POLYVINYL PYROLIDONE 14 G. 
WATER 600 ml. 
ISOPROPYL ALCOHOL 200 ml. 
POTASSIUM IODIDE 8 G. 
SODIUM SULFITE 8 G. 
GUANIDINE CARBONATE 8 G. 
WATER TO MAKE TO 1000 ml. 
II CARBOWAX 400 10 G. 
WATER 600 ml. 
ISOPROPYL ALCOHOL 100 ml. 
ETHYL ALCOHOL 50 ml. 
METHYL CELLOSOLVE 20 ml. 
POTASSIUM IODIDE 4 to 10 G. 
SODIUM SULFITE 4 to 10 G. 
MONOETHANOLAMINE 10 ml. 
WATER TO MAKE TO 1000 ml. 
III WATER 600 ml. 
ISOPROPYL ALCOHOL 150 to 300 ml. 
Potassium Sulfite 4 to 8 G. 
POTASSIUM CARBONATE 4 to 15 G. 
WATER TO MAKE TO 1000 ml. 
______________________________________

The following example is included to facilitate a further understanding of 
the invention. 
EXAMPLE I 
A diffusion transfer reproduction on an 8 inch .times. 10 inch diffusion 
transfer substrate of the word "RECOGNITION" in capital letters was 
prepared acording to Example 2 of U.S. Pat. No. 2,751,300 and the 
resulting print allowed to dry. The image portion of the print consisted 
solely of the word "RECOGNITION" appearing in black letters against a 
clean white background. 
A preparation solution was prepared by admixing 35 grams of polyvinyl 
pyrrolidone, 8 grams of sodium sulfite, and 8 grams of guanidine carbonate 
in 600 milliliters of water at room temperature. After the solids were 
dissolved additional water was added to bring the total solution to 1,000 
ml. This solution had a pH in the range 7.5-11.5. Approximately 20 ml. of 
this solution was swabbed across the face of the diffusion transfer print 
for about 1 minute using a cotton pad. 
A mordanting solution was prepared by admixing 100 grams of potassium 
ferricyanide, 100 ml. of a 3% iodine solution in acetone, 15 grams of 
guanidine carbonate and 25 grams of polyvinyl pyrrolidone in 750 ml. of 
water at room temperature. After the solids were dissolved a sufficient 
amount of water was added to make 1000 ml of solution. 
Three dye baths were prepared by admixing the ingredients in water and 
solvent at room temperature according to the following formulation: 
______________________________________ 
DYE BATH 
______________________________________ 
Polyvinyl pyrrolidone (M.W. 40,000) 
25 grams 
Diacetone alcohol 50 ml 
1-formyl piperdine 60 ml 
0.1 gm Auramine Yellow 
(C.I. 41000) + 1.0 gm Acridine 
Yellow (C.I. 46025) -water to make 
1000 ml 
______________________________________ 
Separate 1000 ml baths were prepared in the same fashion using 2.0 gm basic 
blue #9 (methylene blue color index 52015) and 0.7 basic red #2 (safranine 
O color index 50240) as the respective dye in each instance, the dyes 
provided a vivid intense coloration to the dye bath. 
After resting on the image surface for about one minute, the preparation 
fluid was soaked up by blotting the image with paper toweling and the 
print allowed to dry. 
While the print was drying, approximately 10 ml of the yellow dye bath was 
combined with an approximately equal quantity of the mordanting solution 
in a small glass beaker to form a coloring solution having a pH within the 
range 7.5-11.5 and the mixture agitated with an artist's fine tip paint 
brush. A fluid impermeable Mylar mask was laid down over the word 
"RECOGNITION" except the letters "REC" which remained exposed. The fine 
tip paint brush was used to apply about 5 ml of the premixed yellow 
coloring fluid over the exposed substrate area bearing the letters "REC". 
Application of the fluid was not limited to the imaged letter areas and 
the fluid was also applied onto the background area as well by moving the 
brush back and forth across the letters "REC" and the intervening 
non-image areas. After about one minute of swabbing action and dye 
processing solution was removed from the substrate by blotting with a 
paper towel. The letters "REC" appear in a clear yellow color. The 
background areas appeared lightly pigmented in a yellow tone although the 
white background was clearly visible through the coloration. Thereafter, 
about 10 ml of a fixer solution having a pH in the range 7.5-11.5 prepared 
by admixing 14 grams of polyvinyl pyrrolidone, 200 ml. isopropyl alcohol, 
8 grams potassium iodide, 8 grams sodium sulfite, and 8 grams of guanidine 
carbonate in 600 ml. of water to dissolve the solid ingredients and then 
adding water to make 1,000 ml. was generously applied to the previously 
treated area. The fixer solution was agitated back and forth across the 
treated area for approximately about 1 minute after which time it was 
removed with blotting paper to leave the letters "REC" colored in 
brilliant yellow and the background (non-image areas) clean white and free 
from stain. 
After the print has dried, the mask was moved to expose only the letters 
"OGN". These letters were dyed blue by combining about 10 ml. of the blue 
dye with an approximately equal amount of the mordanting solution in a 
separate beaker and applying about 5 ml. of the resulting blue color 
processing solution to the substrate with a paint brush. The processing 
solution had a pH within the range 7.5-11.5. No further treatment of this 
area with the preparation solution was required. After approximately 1 
minute the excess fluid was removed by blotting with paper toweling and 
the treated area swabbed with a liberal amount of the previously prepared 
fixer solution. After 1 minute the fixer solution was removed by blotting 
to reveal the letters "OGNI" colored in blue with the background clear and 
stainfree. After drying, the same procedure was again repeated to color 
the remaining letters of the word (i.e. "TION") in red by applying about 5 
ml of a coloring solution (prepared by admixing approximately 10 ml of the 
red dye bath with an approximately equal amount of the mordanting solution 
in a separate beaker) to the substrate area including the exposed letters 
and thereafter applying a liberal quantity of fixer solution in the same 
manner as before. 
At the conclusion of this procedure the diffusion transfer photograph of 
the word "RECOGNITION" in which the letters were originally black on a 
white background was converted to a colored image in which the letters 
"REC" were yellow, the letters "OGNI" were blue, and the letters "TION" 
red. 
EXAMPLE II 
The same procedure was repeated as in Example I, except that the word 
RECOGNITION was produced as a positive photographic silver image on a 
transparent polyester film base. The image bearing substrate was treated 
with Preparation solution, dried, and the letter groups REC, OGNI and TION 
respectively masked off, coated with yellow, blue and red dyes, treated 
with fixer solution and dried in the same manner as in Example I. The 
transparent (non-image) areas of the film base remained free of any dye 
coloration or staining after the final treatment with fixer solution. The 
color bearing image areas were optically light transmitting and appeared 
translucent when held up to a 100 watt incandescent light bulb. 
It will be understood by those skilled in the art that the above examples 
are presented by way of illustrating preferred embodiments of the 
invention which is not limited to operation in this fashion. In general, 
the proportions of ingredients to one another in the baths and solutions 
of the invention is not critical and the process will operate in a 
satisfactory fashion provided that the alkaline pH range of 7.5-11.5 is 
maintained and the respective ingredients are dissolved in the solution. 
The preceding examples illustrate the manner of operating the invention 
with a minimum amount of equipment. However, the instant dye coloring 
system may also be carried out in trays, on automatic processing machines 
in which a moving film web is transported by means of rollers from one 
bath to another, in photographic developing tanks and similar processing 
apparatus. The quantity of dye employed in preparing the respective dye 
baths for use in the invention may be varied to a considerable extent 
according to the tinctatorial strength of a particular dye and the degree 
of coloration sought to be obtained in the finally colored image. It is 
also possible to combine different dyes in a given dye bath to achieve a 
wide variety of coloration and hue. 
In most instances stain removal ability can be enhanced by raising the pH 
of the fixer solution. Generally, the fixer solution should be prepared 
with an excess of the alkali constituent in order to avoid staining of the 
background (non-image) areas. In general, as the amount of alkali is 
increased in the fixer solution, the solution's ability to remove dye 
stains from the background area is increased. Similarly, the mordanting 
solution should also contain a stoichiometric excess of alkali to 
counteract the acidic nature of certain dye formulations. 
The fixer solution alters the structure of any remaining unmordanted dye 
and renders it more soluble in the solution. For instance, diphenylmethane 
and triphenylmethane dyes are converted into their carbinol forms, while 
thiazine and acridine dyes are generally more soluble under alkaline 
conditions. 
The quantity of mordanting solution required to be admixed with each 
particular dye bath may vary. As a general rule, the invention will 
operate if a sufficient amount of mordant solution is admixed with a given 
dye bath to insure that the combined fluid admixture has a pH above 7.5 
and preferably in the range 7.5 through 11.5. 
To further facilitate operation of the invention, 8 or 10 dye baths may be 
prepared in advance and held separately from one another in stoppered 
glass bottles. Similarly, the Preparation, Fixer and Mordanting solutions 
may also be prepared in advance and stored in separate, stoppered, glass 
bottles. In operaton, a particular dye bath may be admixed with an 
appropriate quantity of mordanting solution just prior to use, to form the 
color processing solution of the inventon. It has been found that the 
color processing solutions formed by admixing the dye bath and the aqueous 
mordanting solutions are stable for periods up to 4 hours or more, thus 
enabling the same bath to be used in coloring several photographs. 
Accordingly, the present invention will be seen to provide a rapid 
technique for imparting permanent colors to preselected image areas of a 
photographic silver image in which the dye color is taken up 
preferentially by the imaged areas and any excess dye easily removed from 
the non-imaged (background) areas of the photographic substrate. This 
system is especially useful in conjunction with negative and positive 
images produced by photographic diffusion transfer reproduction.