US2434272A - Color photography with azosubstituted couplers - Google Patents

Description

Patented Jan. 13, 1945 COLOR PHOTOGRAPHY WITH AZO- SUBSTITUTED COUPLERS Edwin E. Jelley and Paul W. Vittum, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Application May 3, 1944, Serial No. 533,933

3 Claims. (Cl. 95-6) This invention relates to color photography and particularly to a method for producing stable dye images in photographic layers.

In Glass, Vittum, and Weissberger, U. S. patent applications Serial Nos. 533,930, 533,931 and 533,932, filed May 3, 1944, there are described colored couplers having an azo-substituted reactive methylene group or reactive ethanol group. It has been found that these couplers react with the development product of primary aromatic amino developing agents to form colored photographic images just as the couplers containing unsubstituted reactive methylene or ethanol groups react. The azo group is removed during coupling and an azomethine or indophenol dye is produced.

We have found that these colored couplers containing an azo-substituted reactive methylene or reactive ethanol group may be incorporated in the photographic emulsion layer and may be used to form the final dye image. According to the process, the emulsion layer contains a coupler having the color desired for the final dye image. After exposure of the layer, it is developed with a coupling developing agent, such as diethyl-p-phenylenediamine during which step the coupler color is destroyed at the points where development occurs leaving at these points an azomethine or indoaniline or indophenol dye image in place of the colored coupler originally present. At the places where no development occurs, the colored coupler is left intact. The layer is then subjected to a suitable treatment, such as a strong acid bath which destroys and removes the coupled dye without aiTecting the original colored coupler. The residual silver and silver halide are then removed, leaving a reversed dye image composed of the originally incorporated colored coupler.

The following colored couplers are suitable for incorporation in photographic layers according to our invention as well as the couplers described in Glass, Vittum and Weissberger U. S. patent applications Serial Nos. 533,930, 533,931 and 533,952 referred to above.

(3) $03K OCH; OCH: S0311 $0311 I SO3H It will be seen that the color of the dye formed during color development is of no importance since this dye is removed. The color of the original coupler is chosen to fulfill the requirements for the final dye image.

The colored coupler is incorporated in the silver halide emulsion layer which is generally of the gelatino-silver bromide type, by forming the sodium salt of the coupler and dissolving the solution directly in the emulsion prior to coating or by incorporating the coupler in a solution of a water-insoluble, water-permeable solvent as described in Mannes and Godowsky U. S. Patent 2,304,940 or our prior Patent 2,322,027. The amounts of coupler employed will generally vary between 1.0 gram and 10 grams per liter of wet emulsion. Thelayer containing the coupler is exposed in the usual way and is then developed in any of the usual color developers, such as pphenylenediamine or p-aminophenol. A typical developer formula is as follows:

p-Aminodimethylam'line HCl grams 3 Sodium sulfite do 2 Potassium bromide do 2 Sodium carbon do 20 Water to l ers 1 Hydrochloric acid concentrated cc 50 Water c-.. Isopropyl alcohol cc 850 The layer is then treated with solutions of ferricyanide and hypo in the usual way to remove undeveloped silver and residual silver halide. The fragments of the coupled dye destroyed by the acid treatment are also removed either by this treatment or by the preceding acid treatment.

The removal of the silver and residual silver halide may be carried out prior to the acid treatment, or the acid treatment and the fixing may be carried out simultaneously.

Our process can be adapted to single layer or multi-layer materials. In the latter case the ma: terial may be arranged in the known manner to give natural-color reversal pictures. For example, the red-sensitive layer containing cyan-col;- ored coupler would be coated on the support followed by the green-sensitive layer containing magenta-colored coupler and the blue-sensitive layer containing yellow-colored coupler. In this material, it would be advantageous to have sensitivity maXima which do not correspond with the absorption maxima of the colored couplers. Our process may also be adapted to other known arrangements, such as, those leading to false color pictures.

It is advantageous in certain cases when using multi-layer materials to incorporate the colored coupler in only a single layer or in less than all of the emulsion layers of the coating. The remaining emulsion layers might contain colorless couplers incorporated directly in the emulsion layer in the usual Way or incorporated in waterpermeable, water-insoluble solvents as described in the Marines and Godowsky U. S. Patent 2,304,949 and in our prior Patent 2,322,027 referred to above. It might also be advantageous to have one or more of the layers of the multilayer coating free of coupler so that the dye image could be formed in this layer by means of a coupler dissolved in the developing solution.

Several advantages accrue from the use of a system having colored couplers in less than all of the layers of a multi-layer coating and colorless couplers in the remaining emulsion layer. The layers containing the colored coupler would produce a positive image upon direct development in a color-forming developer, whereas. the layers containing the colorless couplers produced a negative image. camera material is, therefore, a mixture of negative and positive components. However, by printing onto a similarly constituted paper or other printing material, a normal positive is obtained. A further advantage in the case of multi-. layer materials coated in the normal order, that is with the blue-sensitive layer outermost, is that the yellow filter layer normally coated between the top and middle emulsion layers can be dispensed with by use of a blue-sensitive emulsion layer containing a yellow-colored coupler. Furthermore, by using a magenta-colored coupler in the green-sensitive emulsion layer as well as a yellow-colored coupler in the blue-sensitive emulsion layer, red light, only would reach the bottom red-sensitive layer so that not only would no yellow filter be, required but also the red-green color separation would be improved.

A still further advantage in the use of both colored and uncolored couplers is the possibility of i proving the overall stability of the finaldye images. 'In color processes in which eolorlesscow. plers are incorporated in the emulsion layers, it is not unusual to find that one or? the final dye images is much less stable than the other two. The present proposal would permit. the se of, a

The picture obtained on the colored coupler having higher stability than the unstable colorless coupler, so that the stability of the final dye images could be matched. This advantage is of course due to the higher stability of the azo dyes and is inherent in the colored couplers which we propose to use. Generally, the colored couplers containing azo groups may be selected to produce higher fastness to heat and light than can be obtained with the azomethine or indoaniline dyes normally obtained in colordevelopment processes.

In a specific embodiment of the use of a colored coupler in one of the layers of a multi-layer coating and colorless couplers in the other layers,

'asupp ort of filrn or paper may be coated first with a red-sensitive silver halide emulsion containing a dispersion of a coupler capable of yield- .jing a cyan dye on development, followed by a clear interlayer, a green-sensitive silver halide emulsion containing a dispersion of a, coupler capable of yielding a magenta dye on development, another clear interlayer, and then a, bluesensitive silver halide emulsion containing a dispersion of a yellow-colored coupler capablev of being destroyed on development to yield, an easily removable azomethine dye. An anti-abrasion layer of clear gelatin may be coated as the final layer.

In this system, the red-sensitive emulsion layer may contain as the cyan coupler o-lauryl phenol incorporated directly in the emulsion or a dispersion of (l) 2-0:-(4'-tert.amylphenoxy )-butyrylamino-l-phenol or (2) 5- (N- (v-phenylpropyl) N-(p-amylbenzoyl) amino) 1' naphthol, in n,- butyl phthalate or tri-orthocresylphosphate age cording to the method of our prior Patent 2,322,027.

The green-sensitive emulsion layer may con,- tain a dispersion of (1) 1-phenyl 3;n-pentadecy1 S-pyrazolone, (2) 1-phenyl-3:palrnitylamino-E: pyrazolone, or (3) l-cyanoacetyl-g-tert.amyldiphenyl. A dispersion in n-ainylphthalate, ethyl sebacate, or N-nr-amylphthalimide according to our prior Patent 2,322,027 of (1) 1-p-.(p,.- tertbutylphenoxy-phenyl) -3- m (p tertamyl-H phenoxybenzoylamino)-5-pyragolone, or (2) 2- cyanoacetylcournarone-5-sulfon- N ('y phenylw propyl) -p-tert.amylanilide may also be used. All ofthese couplers produce magenta d es.

The blue-Sensitive. mulsion. lay r a c ntai a dispersion of one of the following yellow-colored couplers dispersed directly in the, emulsion layer or used with a coupler solv nt as described in ourprior Patent 2,322,027:

ing developer and then removing the azomethi-ne dye from the originally blue-sensitive layer and also removing all of the silver and silver halide is shown in the following diagram:

6 linked to said reactive group and to an aryl radical, exposing said layer and developing it with a primary aromatic amino developing agent which simultaneously destroys the azo linkage It is apparent from this chart, which represents the three emulsion layers and shows the color of the image produced by exposure to various colors and the colors obtained by passing white light through the material as in printing, that the colors obtained in the negative bear no direct relation to the colors of the original. This material would not give a positive copy by reversal processin but upon printing the negative onto a similar material the colors of the original are reproduced.

For processing a material of this type a normal color developer is employed, that is one containing as the developing agent a primary aromatic washed, treated with an acid bath to remove the azomethine dye from the top emulsion layer, such as the acid loath listed above, treated with ierricyanide to convert the silver to silver ferrocyanide, and finally treated with hypo to remove the silver salts. 4

Since it is advantageous in some cases to confine the use of the acid dye bleach bath to the upper lay or layers, this bath may contain loading agents to control its penetration. The steps involving the use of the acid bleach bath and the ferricyanide bath can be combined by using a hydrochloric acidquinone bath, such as that described in column 2, lines 17 to 22, of Mannes and Godowsky U. S. Patent 2,113,329.

With the colored couplers used according to our invention, insolubilizing groups may be present in the coupler molecule to render the couplers non-diifusing in the emulsion layer or layers in which they are incorporated. These groups may be so chosen that the fragments of the coupler obtained after development and acid treatment will be small enough to permit easy diffusion and removal from the film.

It will be understood that our invention is capable of numerous modifications not herein 55 specifically mentioned and that our invention is to be taken as limited only by the scope of the appended claims.

We claim:

1. The method of producing a colored image in a photographic silver halide layer, which comprises incorporating in said layer a colored coupler having an azo-substituted reactive group selected from the class consisting of methylene and ethanol groups, the azo linkage being directly and forms a dye image in the exposed regions by coupling of the development product of the developer with the residue of the colored coupler, treating said layer with an acid solution to destroy said coupled dye image Without affecting said colored coupler, and removing silver and silver halide from said layer along with the destroyed coupled dye image.

2. The method of producing a colored image in a photographic silver halide layer which comprises incorporating in said layer a colored coupler having an azo-substituted reactive methylene group, the azo linkage being directly linked to said reactive group and to an aryl radical, exposing said layer and developing it with a primary aromatic amino developing agent which simultaneously destroys the azo linkage and forms a dye image in the exposed regions by coupling of the development product of the developer with the residue of the colored coupler, treating said layer with an acid solution to destroy said coupled dye image without afiectin said colored coupler, and removing silver and silver halide from said layer along with the destroyed coupled dye image.

3. The method of producing a colored image in a photographic silver halide layer which comprises incorporating in said layer a colored coupler having an azo-substituted reactive ethanol group, the azo linkage being directly linked to said reactive group and to an aryl radical, exposing said layer and developing it with a primary aromatic amino developing agent which simultaneously destroys the azo linkage and forms a dye image in the exposed regions by coupling of the development product of the developer with the residue of the colored coupler, treating said layer with an acid solution to destroy said coupled dye image without afiecting said colored coupler, and removing silver and silver halide from said layer along with the destroyed coupled dye image.

EDWIN E. JELLEY. PAUL W. VITTUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,322,001 Ehrenfried June 15, 1943 (Other references on following page) Number Woodward Feb. 22, 1944 Name Date Schinzel Jan. '7, 1941 Schinzel Nov. 18, 1941 Peterson Jan. 12, 1943 Woodward Oct. 6, 1942 FOREIGN PATENTS Country Date Great Britain Apr. 11, 1939