US3536486A

US3536486A - High temperature processing of exposed photographic elements

Info

Publication number: US3536486A
Application number: US796172A
Authority: US
Inventors: Leo E Beavers
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1969-02-03
Filing date: 1969-02-03
Publication date: 1970-10-27
Anticipated expiration: 1987-10-27

Description

United States Patent 3,536,486 HIGH TEMPERATURE PROCESSING OF EXPOSED PHOTOGRAPHIC ELEMENTS Leo E. Beavers, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Feb. 3, 1969, Ser. No. 796,172

Int. Cl. G03c 5/50 US. Cl. 96-22 31 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to photographic processes, and more particularly to photographic processes for providing multicolor reproductions.

The dyes employed in providing multicolor photographic reproductions are not always true colors. For

example, magenta dyes often have small amounts of blue I light absorption and red light absorption. Similarly, yellow dyes and cyan dyes absorb small amounts of light other than blue and red light, respectively. The effects of such unwanted absorptions by dyes employed in photographic multicolor processes is the production of dark and desaturated colors or color hue errors.

Such deficiencies in dyes employed in multicolor photographic processes can be compensated, at least in part, by creating certain interimage effects. The interimage effects to which this invention pertains are referred to herein as undercut interimage effects. In accordance with this invention, novel means are provided for inducing undercut interimage effects in processes for providing multicolor photographic reproductions.

It is one object of this invention to provide a novel method for correcting unwanted absorptions of dye images formed in photographic multicolor processes.

It is another object of this invention to provide a novel method for providing undercut interimage effects in photographic multicolor processes which utilize at least one photographic silver haloiodide emulsion layer.

It is a further object of this invention to provide a novel method for introducing undercut interimage effects in photographic processes for providing multicolor images.

It is still another object of this invention to provide multicolor photographic processes which result in increased contrast, speed, sharpness and reduced color contamination.

Still other objects of this invention will be apparent from the disclosure herein and the appended claims.

In accordance with one embodiment of this invention, an improvement is provided in photographic multicolor processes which includes (1) developing silver images in 3,536,486 Patented Oct. 27, 1970 an exposed photographic element having at least two superposed hydrophilic colloid layers containing lightsensitive silver halide, and (2) forming differently colored dye images in proportion to said silver images. This improvement resides in introducing a diffusible 4-thiazoline- 2-thione into the exposed photographic element so that 4-thiazoline-2-thione is present during development of the silver images. When a diffusible 4-thiazoline-2-thione is present during the formation of silver images in multicolor photographic processes of the type described above, undercut interimage effects are obtained in the completed multicolor photographic reproduction.

'Interimage effects are Well known in photographic multicolor processes. See, for example, Hanson and Horton, Journal of the Optical Society of America, vol. 42, No. 9, pages 663-669, September 1952, and Pinney, Interimage Effects and Color Reproduction, The SPSE Reporter, November 1960. The interimage effects produced by the present invention are referred to herein and in the appended claims as undercut interimage effects. Undercut interimage effects are characterized by repression of a given color scale produced by a neutral exposure, and the lack of such repression for that color scale in a single color exposure.

A more specific, hypothetical example will further illustrate the meaning of undercut interimage effects. A photographic element is provided containing two light-sensitive silver halide emulsion layers. One of these layers is sensitive to red radiation and is adapted to form cyan dye. The second layer is sensitive to blue radiation, and forms yellow dye. One sample of such a film is given a stepped exposure to red light. A second sample is given a stepped exposure to red plus blue light. The amount of red light is the same in each exposure. Undercut interimage effects are present when the cyan dye produced from the exposure to red light only is less than the cyan dye produced from the exposure to red plus blue light. A similar analysis can be made for other dye images, such as red, green, blue, magenta and yellow.

Undercut interimage effects result in more saturated and brighter dye images. These interimage effects can be measured by the procedures described by Pinney or Hanson and Horton, referred to above.

As noted, the compounds employed in this invention to induce undercut interimage effects include the diffusible 4-thiazoline-2-thiones. These compounds generally are, at least in solution, in equilibrium with their corresponding mercaptan forms. The compounds should be capable of forming a complex with silver halide, thereby rendering the compound non-diffusible unless the silver halide is developed to a silver image. One especially useful class of 4-thiazoline-2-thione compounds has, in the 4-position thereof, an alkyl substituent having a carbonyl or hydroxyl group. As used herein and in the appended claims, the term carbonyl has its usual meaning, i.e., =C=O. Typical useful alkyl substituents containing a carbonyl group include formyl, carboxyl, alkoxy- Icarbonyl, e.g., ethoxycarbonyl, and allkoxyalkyl, e.g., acetoxymethyl. Another highly useful class of 4-thiazoline-Z-thiones contains an alkyl substituent in the 4-position thereof, said alkyl substituent consisting of from 4 to 5 carbon atoms, each of the carbon atoms having a hydroxyl group attached thereto. As used herein, the term 4-thiaz0line-2-thione refers to the 3-hydrogen subgeneral formula:

l N X'- wherein X represents alkyl such as methyl or ethyl; an alkyl substituent containing at least one hydroxyl group such as hydroxy methyl, [i-hydroxyethyl, gluco or arabino; or an alkyl substituent having at least one carbonyl-containing group such as formyl, carboxyl, ethoxy carbonyl or acetoxy methyl; and, Z is independently se ected from a value given for X, and preferably represents hydrogen. Advantageously, the 4-thiazoline-2-thione compound employed is one which can emolize to its corresponding mercaptan form. Enolization can take place at any suitable time, such as when the 4-thiazoline- 2-thione is added to a hydrophilic colloid layer containing light sensitive silver halide.

Representative dilfusible 4-thiazoline-2-thiones which can be advantageously employed in the practice of this invention include the following:

(3) 4-carboxy-4-thiazoline-2-thione COOH TNH l l. S

(4) 4-carboxy-5-methyl-4-thiazoline-2-thione COOH I EI l r (5) 4-carbethoxy-4-thiazoline-2-thione (6) 4-acetoxymethyl-4-thiazoline-Z-thione 4 (7) 4-(D-arabino-tetraacetoxybutyl)-4-thiazoline-2- o 11 0 020E H H0 0 o o 0 Ha HC 0 o 0 CH3 orrzocoorr (8) 4- D-gluco-penta-acetoxypentyl) -4-thiazoline-2- thione l g H H I OCOCH CH3CO2CH HCOOOCH l HCOOOCH;

C HzOCOCHs (9) 4- (D-gluco-penta-hydroxypentyl) -4-thiazoline-2- thione HC OH HOOH HJJOH l ENIJOH CHaOH (l0) 4-hydroxymethyl-4-thiazoline-2-thione N H l E3011 11) 4-methyl-4-thiazoline-2-thione 12) 4-(D-arabino-1,2,3,4-tetrahydroxybutyl)-4- thiazoline-Z-thione As is known, several isomers of compound 12 exist; Any of these isomers, or mixtures thereof, can be employed in accordance with this invention to produce undercut interimage effects.

The 4-thiazoline-2-thiones employed in this invention are ditfusible in hydrophilic colloids. As used herein, the term ditfusible denotes materials having the property of moving effectively through the colloid layers of the photographic elements employed. Thus, it follows that any substituents on the subject compounds should not, alone or in their combined action, prevent diffusion of the compounds through the colloid layers employed in the photosensitive element. In short, the substituents of such compounds should be non-ballasting. Although we do not wish to be limited to any theory as to the nature of the operation of the invention, it seems reasonable to believe that the 4-thiazoline-2-thiones become attached to silver halide crystals, and are prevented from diffusing freely through the colloid layers of the photographic element. However, when the silver halide is developed to silver image, it seems that the 4-thiazoline-2-thione is thus released and is diffused imagewise in the system, and probably inhibits development.

In order to obtain undercut interimage effects in accordance with the invention, the diffusable 4-thiazoline-2- thiones must be present in the photosensitive element during the development of silver image (i.e., the initial development of silver image). The photosensitive element can also be treated subsequent to exposure, such as "with an aqueous solution containing the diifusable interimage producing addenda of the invention. Such aqueous solutions can contain various photographically useful reactants, such as prehardener. The compounds of the invention can also be added to the developer solution employed to develop silver image in the exposed photographic element.

The effective concentration of the addenda in accordance with this invention can be varied over a considerable range. The concentration employed depends on the particular light sensitive silver halide emulsions utilized, the concentration of silver halide in the emulsion layers, and the concentration of dye to be formed. A highly useful concentration range of addenda is from about 0.1 mg. to about 1.0 g. addenda per liter of solution (such as blackand-white developer solution) with about 1.0 mg. to 50 mg. addenda per liter of solution being the range generally preferred.

The 4-thiazoline-2-thione undercut interimage producers can be used to advantage with any compound which functions to develop silver image in a silver halide layer containing a latent image. Highly useful classes of silver image developing agents include the polyhydroxy benzenes, N-monoalkylamino phenols and mixtures of polyhydroxy benzenes and N-monoalkylamino phenols. Typical useful polyhydroxy benzenes include hydroquinone, catechol, pyrogallol, etc., and typical useful N-substituted aminophenols include N-methylamino phenols, N-ethylamino phenols, etc., or mixtures of such developers. Prominent among such developing agents are those which provide rapid development of photographic images comprising hydroquinone and p-N-methylarnino phenol. The developing agents with which the undercut interimage increasing addenda of this invention can be used include dye developers, such as those disclosed and referred to in Weyerts et al. U.S. Pat. 3,146,102 issued Aug. 25, 1964, and Rogers U.S. Pat. 2,983,606 issued May 9, 1961. The addenda of this invention can also be used in the photographic color processes described in Whitmore et al., U.S. Pat. 3,227,550, issued Sept. 7, 1962; Barr et al., U.S. Pat. 3,227,551, issued Jan. 4, 1966; Whitmore U.S. Pat. 3,227,552, issued Jan. 4, 1966; Barr et al. U.S. Pat. 3,227,554, issued Jan. 4, 1966; or Barr U.S. Pat. 3,243,- 294, issued Mar. 29, 1966.

Desirable undercut images are obtained in accordance with this invention when the processing is conducted at conventional temperatures, such as about 68 to 75 F., or when higher processing temperatures are employed, such as from 75 F. up to about 180 F., or higher.

The undercut interimage producing addenda of this invention can be used in any process of providing multicolor photographic reproductions which includes (1) developing silver images in an exposed photographic element having at least two superposed hydrophilic colloid layers containing silver halide, and (2) forming differently colored dye images in proportion to said silver images. For example, the addenda are highly useful in complete photographic reversal processes wherein a multilayer photographic element containing a plurality of differentially sensitized photographic silver halide emulsion layers is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image, and a second exposure followed by at least one additional development in a photographic developer for producing a colored dye image. In such systems, the dye image may be provided in one of two classical techniques. In one, color couplers are incorporated in or contiguous to the photographic emulsions prior to exposure. Gen erally, the color forming couplers are dispersed in a suitable medium, such as one of those described in US. Pats. 2,322,027 or 2,304,940. Representative useful color formers which may be used in such processes are well known in the literature, and are described for example, in Fierke et al., U.S. Pat. 2,801,171; Weissberger et al., U.S. Pat. 2,474,293; Glass et al., U.S. Pat. 2,521,908; and Mc- Crossen et al., U.S. Pat. 2,857,057. Such elements can be developed by one of the processes described and referred to in Graham et al. U.S. Pat. 3,046,129, col. 23 and 24. General classes of useful color formers include phenolic, S-pyrazolone, and open chain ketornethylene compounds.

The second of such color reversal photographic processes is characterized by the introduction into the photosensitive element of dye former contained in the developer. In such processes, couplers of the type referred to above can be incorporated in a color developer solution. These processes are described in the literature, such as Mannes et al., U.S. Pat. 2,252,718, issued Aug. 19, 1941.

The color forming developers which can be used in accordance with the two processes described above have been previously described in the art. The most useful of such color forrning developers are the phenylene diamines and substituted derivatives thereof, such as those disclosed in Weissberger et al., U.S. Pat. 2,548,574, issued Apr. 10, 1951; Weissberger et al., U.S. Pat. 2,552,- 240-2 issued May 8, 1951; and Weissberger et al., U.S. Pat. 2,566,271, issued Aug. 28, 1951. Other phenylene diamine color forming developers can be employed to advantage in the process of this invention.

This invention is also applicable to other photographic processes for forming multicolor images, such as color diffusion transfer processes of the type described in Rogers U.S. Pat. 2,983,606, issued May 9, 1961; Weyerts U.S. Pat. 3,146,102, issued Aug. 25, 1964; Barr et al. U.S. Pat. 3,227,551, issued Jan. 4, 1966; Barr et al. U.S. Pat. 3,227,554, issued Ian. 4, 1966; Barr U.S. Pat. 3,243,- 294, issued Mar. 29, 1966; Whitmore et al., U.S. Pat. 3,227,550, issued Jan. 4, 1966; and Whitmore U.S. Pat. 3,227,552, issued Aug. 27, 1964.

The novel addenda of this invention can also be employed to advantage in photographic processes which provide dye images by the photographic silver dye bleach process. In such processes, which are described in the literature, bleachable dye is incorporated in or contiguous to a given silver halide layer, a silver image is produced after exposure, and the dye is bleached imagewise in proportion to the silver image developed to provide contrasting dye images.

As is known, one highly useful arrangement of light sensitive silver halide layers for the provision of multicolor photographic records comprises a support having coated thereon, respectively, superposed light sensitive silver halide colloid layers which are sensitive, respectively, to red, green and blue radiation. Silver images can be developed in such layers, and dyes formed imagewise in proportion to the developed silver image. Advantageously, cyan, magenta and yellow dyes are formed in proportion to the red, green and blue layers respectively. Such dyes can be formed in any convenient manner, such as in the color processes referred to above. Advantageously, a dye image is formed having a complementary relationship to the region of the spectrum to which the silver halide emulsion is sensitized.

The addena which has been described herein can be added to emulsions containing various light sensitive silver halide salts, such as silver bromide, silver iodide, silver chloride, or mixed silver halides, such as silver chlorobromide, silver bromoiodide or silver chlorobromoiodide. Best results are obtained when at least one emulsion layer contains silver haloiodide, such as silver chloroiodide, or preferably silver bromoiodide (or silver bromochloroiodide). Advantageously, the silver haloiodide contains from 1 to 10 mole percent, and preferably 4 to 8 mole percent, iodide. The emulsions can contain various chemical sensitizers, optical sensitizers, stabilizers, speed increasing compounds, plasticizers, hardeners and coating aids, such as are described and referred to in Beavers US. Pat. 3,039,873, issued June 19, 1962, cols. 9-12. The light sensitive silver halide salts can be dispersed in various binders, such as the colloids described and referred to in aforementioned Beavers patent, col. 13. Any suitable support can be used, such as a cellulose ester, poly(ethylene terephthalate), paper, baryta coated paper, polyolefin coated paper such as polyethylene or polypropylene coated paper, which can be electron bombarded to promote emulsion adhesion. Emulsion layers having different speeds can be utilized to extend the latitude of the element.

The following examples are included for a further understanding of the invention. In the examples, two types of photographic elements are employed. The first element, referred to herein as Type I, is prepared by coating a transparent poly(ethylene terephthalate) film support with the following hydrophilic colloid layers, in the order in which they are given starting from the support:

TYPE I Layer A-antihalatin A dispersion of gray colloidal silver in gelatin is coated over the support at a concentration of 455 milligrams per square foot gelatin and 23 milligrams per square foot gray colloidal silver.

Layer B-interlayer A gelatin interlayer is coated over the antihalation layer at the rate of 115 milligrams gelatin per square foot.

Layer C-cyan-producing layer A gelatin silver bromoiodide emulsion containing a dispersion of a mixture of cyan-forming coupler, e.g., couplers Nos. 1 through 6 of Fierke et al. U.S. Pat. 2,801,171 (column 2) in conventional coupler solvent such as tri-o-cresyl phosphate is coated at the rate of 110 milligrams per square foot gelatin, 65 milligrams per square foot silver and 50 milligrams per square foot cyan coupler mixture. Red sensitization (600-700 mg) is provided with spectral sensitizing dye.

Layer D-interlayer A gelatin layer coated at the rate of 60 milligrams gelatin per square foot.

Layer E-magenta-producing layer A silver bromoiodide gelatin emulsion spectrally sensitized to green radiation (500-600 m with a spectral sensitizing dye and containing a dispersion in tri-o-cresyl phosphate of a pyrazolone coupler, e.g., couplers number 7 etc. of Fierke et al. US. Pat. 2,801,171 (column 2) together with a pyrazolone coupler, e.g., coupler number 8 of US. Pat. 2,801,171 is coated at the rate of 165 milligrams per square foot gelatin, 95 milligrams per square foot silver and 65 milligrams per square foot coupler mixture.

Layer Fyellow filter layer A gelatin layer containing Carey-Lea colloidal silver is coated at the rate of 90 milligrams per square foot gelatin, and 10 milligrams per square foot silver.

Layer Gyellow-producing layer A gelatin silver bromoiodide emulsion (blue-sensitive) containing a yellow image-forming coupler, e.g., coupler Nos. I to V of McCrossen et al., US. Pat. 2,875,057, issued Feb. 24, 1959, dispersed in dibutyl phthalate is 8 coated at a concentration of 115 milligrams per square foot gelatin, 70 milligrams per square foot silver and 50 milligrams per square foot color coupler.

Layer H-overcoat layer A gelatin layer is coated at the rate of milligrams per square foot gelatin.

In the following examples, all elements of Type I are processed in the following reversal color process: first, the exposed film is developed for 10 minutes in a Developer A having the following composition:

Sodium hexametaphosphate-2.0 g. N-methyl-p-aminophenol sulfate6.0 g.

Sodium sulfite, anhydrous50.0 g.

Hydroquinone6.0 g.

Sodium carbonate monohydrate-35 .0 g.

Potassium bromide-2.0 g.

Sodium thiocyanate1.5 g.

0.5% solution of 6-nitrobenzimidazole nitrate12.0 cc. 0.1 solution of potassium iodide-40.0 cc.

Water to make 1 liter.

The element is then thoroughly washed for one minute with water and treated for 3 minutes in a hardening bath having the following composition:

Postassium chrome alum crystals30.0 g. Water to make 1 liter.

The element is then thoroughly washed for 3 minutes with water and treated for 30 seconds in a solution having the following composition:

Sodium borohydride0.25 g. Sodium hydroxide-40 g. Water to make 1 liter.

The element is then treated for 15 minutes in a color developer having the following composition:

Sodium thiosulfate--150.0 g. Sodium bisulfite20.0 g. Water to make 1 liter.

The element is then treated for 8 minutes in a bleach bath having the following composition:

Potassium dichromate5.0 g. Potassium ferricyanide70.0 g. Potassium bromide-20.0 g. Water to make 1 liter.

The element is again washed for one minute and treated for 4 minutes with the clearing and fixing bath identified above. The element is washed for 8 minutes and treated for one minute in a stabilizing bath having the following composition:

Formaldehyde (37% by weight)7.0 cc. Dispersing agent 0.5 g. Water to make 1 liter.

1 Such as Triton X100, i.e., on alkylaryl p'olyether alcollOl (octylphenoxy polyethoxy ethanol).

The above processing is referred to as Processing Procedure I in the examples. The temperature of each bath and solution in this processing is 75 F.

The second type of photographic element employed in the following examples, Type II, is the same as Type I except that Type II elements do not contain any incorporated color-former. These Type II elements are processed by a procedure of the type described in Mannes et al. US. Pat. 2,252,718, issued Aug. 19, 1941, page 2, col. 2, line 48 through page 3, col. 1, line 5. This processing is referred to in the examples as Processing Procedure II and is defined more fully below:

PROCESSING PROCEDURE II Step: Time Prehardener 2 min. Water wash 30 sec. MQ Developer 3 min. 40 sec. Water wash l min. Red light exposed through support. Cyan Developer 4 min. 30 sec. Water wash 2 min. Blue light exposed through emulsion. Yellow developer 4 min. Water wash 2 min. Borohydride bath 1 min. Water Wash 30 sec. Magenta developer 5 min. 30 sec. Water wash 4 min. Ferricyanide bleach 2 min. Hypo Fix bath 2 min. Water wash 4 min. Dry.

The solutions have the compositions given below:

Prehardener:

Sodium hexametaphosphate0.5 g. Sulfuric Acid1.7 m1. Sodium tetraborate 5H O .0 g. Sodium bromide2.0 g. Sodium sulfate200.0 g. Formalin (37.5 %)20.0 ml. Sodium bisulfitel.0 g. Water to make-1 liter. developer: Sodium hexametaphosphate0.6 g. Sodium sulfite79.0 g. Monomethyl-p-aminophenyl sulfate5.0 g. Sodium hydroxide1.0 g. Hydroquinoneg. Sodium carbonate-35.0 g. Potassium iodide (0.1%)-12.5 ml. Sodium bromide3.0 g. Sodium thiocyanate1.7 g. Hydroquinone monosulfate4.0 g. Water to make 1 liter. Cyan developer:

Sodium hexametaphosphate--0.6 g. Sodium bromide-2.5 g. S-nitrobenzimidazole nitrate (1% in .1% NaOH) 3.0 ml. Potassium iodide (0.1% )l 1.0 ml. Sodium sulfite10.0 g. Sodium sulfate-60.0 g. Sodium hydroxide3.8 g. Sodium thiocyanate1.0 g. Hydroxylamine sulfate0.65 g. 4 amino N ethyl-N-B-hydroxyethyl-3-methyl aniline sulfate2.05 g. l-hydroxy N (Z-acetamidophenethyl)-2-naphthamide-1.65 g. Hexylene glycol-50 ml. Polyoxyethylene (m. wt. 1540)-1.0 g. N-benzyl-p-aminophenyl.45 g. Methanol2.0 ml. p-Aminophenol.16 g. Water to make 1 liter.

10 Yellow developer:

Sodium hexametaphosphate-0.6 g. Sodium sulfite10.0 g. Sodium bromide.55 g. Polyoxyethylene (m. wt. 4000)1.0 g. Potassium iodide (0.1% )26.0 ml. N,N-diethyl-p-phenylenediamine HCl-3.0 g. 5-nitrobenzimidazole-10.0 ml. Sodium hydroxide2.l g. Sodium sulfate-64.0 g. Hexylene glycol10.0 ml. ot-Benzoyl-2-methoxyacetanilide1.5 g. Diethylhydroxylamine-1.38 ml. 1-phenyl-3-pyrazolidone-0.5 g. Water to make 1 liter. Borohydride bath:

Sodium hexametaphosphate0.6 g. Sodium hydroxide- 2.16 g. Potassium borohydride-0.l0 g. Water to make 1 liter. Magenta developer:

Sodium hexametaphosphate4.0 g. Sulfuric acid-21 ml. Sodium phosphate12H -40.0 g. Sodium sulfite5.0 g. Sodium thiocyanatel.0 g. Potassium iodide (0.1% )7.5 ml. Sodium bromide-0.5 g. Sodium sulfate-60.0 g. 4 amino-N-ethyl-N-(p-methane-sulfonamidoethyl)- m-toluidine sesquisulfate monohydrate-2.9 g. Citrazinic acid-0.72 g. Ethylenediamine3.0 ml. Polyoxyethylene (in. wt. 4000)-10.0 ml. Hexylene glycol-10.0 ml. 1-(2,4,6-trichlorophenyl) 3 (4-nitroanilino)-5- pyrazolone1.67 g. Sodium hydroxide0.32 g. Water to make 1 liter. Ferricyanide bleach bath:

Sodium bromide-35.0 g. Potassium ferricyanide-10H O200.0 g. Sodium hydroxide0.1 g. Sodium tetraborate-5H O-1.0 g. Water to make 1 liter. Hypo fix bath:

Sodium thiosulfate220.0 g. Sodium sulfite-10.0 g. Sodium hydroxide.15 g. Water to make 1 liter.

EXAMPLE 1 Several photographic elements of Type 1 are prepared. Separate areas of each of these elements are given a single color sensitometric exposure to red, green and blue light, respectively. Unexposed portions of each photographic element are then given an equivalent neutral sensitometric exposure consisting of red plus green plus blue light. The red, green and blue of the neutral exposure is the same as the single color red, green and blue exposures, respectively. One exposed element is processed by Processing Procedure I; the other exposed elements are processed in the same way except that a 4-thiazoline-2-thione is added to Developer A of Processing Procedure I. Density curves are plotted for each of the cyan, magenta and yellow dye densities formed from the red, green and blue light exposures, respectively, and for the respective cyan, magenta and yellow dye densities formed by the neutral exposure. The resulting single color density curves are compared for speed (A log E) to the same color density curves of the neutral exposure at 0.6 density. The improvement in undercut interimage effects is shown in Table I, and is indicated by the increased A log E speed at 0.6 density of a given color scale compared with the corresponding color scale resulting from the neutral exposure.

TABLE I Concentration of A log E at 0.6 density addenda in Addenda developer A Cyan Magenta Yellow Control 13 03 11 Compound 12 4.2 X 10* moles 29 06 18 per liter.

Several photographic elements of Type II are prepared and exposed as described in Example 1. The exposed photographic elements are processed by Processing Procedure II above, except that in processing the test ele ments, 100 mguof compound 12 is added to the prehardener. The A log E at 0.6 density is determined, with the results shown in Table II.

TABLE II Concentration of A log E at 0.6 density Addenda in Addenda prehardener Cyan Magenta Yellow Control 1 05 1.5 Compound 12 100 mg. per liter. 3 2 2 Essentially similar results are obtained when compounds 2, 7 or 9 are substituted for compound 12. Also, substantially identical results are obtained when compound 12 is incorporated in the bath following the prehardener, or in the MQ developer, rather than in the prehardener.

The highly unobvious nature of this invention is emphasized by the fact that compounds closely related to 4-thiazoline-2-thiones, such as 3-carboxyethyl-4-methyl thiazoline 2 thione; 2,2 dithio[5,4 (1,2 D- tritylgluco)]-thiazole; 2-arnin05-thiaz0le carboxylic acid; or, di-(2-amino-4methylthiazole-S-yl)-sulfide, do not produce undercut interimage effects.

The invention has been described in detail with particular reference to preferred embodiments thereof, but, it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

I claim:

1. In the process of providing multicolor photographic records which includes (1) developing silver images in an exposed photographic element having at least two superposed hydrophilic colloid layers containing lightsensitive silver halide, and (2) forming differently colored dye images in proportion to said silver images: the improvement which comprises introducing a diffusible 4- thiazoline-Z-thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver images, whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction.

2. A process of providing multicolor photographic records as defined in claim 1 wherein the silver halide of at least one of said layers comprises a silver haloiodide.

3. A process of providing multicolor photographic records as defined in claim 2 wherein said 4-thiazoline-2- thione has, in the 4-position thereof, an alkyl substituent having a group selected from the class consisting of carbonyl and hydroxyl.

4. A process of providing multicolor photographic 12 records as defined in claim 2 wherein said 4-thiaZoline-2- thione contains an alkyl substituent in the 4-position, said alkyl substituent consisting of from 4 to 5 carbon atoms, each of said carbon atoms having a hydroxyl group attached thereto.

5. A process of providing multicolor photographic records as defined in claim 2 wherein said 4-thiazoline-2- thione contains, in the 4-position thereof, a substituent selected from the group consisting of formyl, carboxyl, ethoxycarbonyl, hydroxymethyl, and acetoxymethyl.

6. In the process of providing multicolor photographic records which includes (1) developing silver images in an exposed photographic element having at least two superposed hydrophilic colloid layers containing lightsensitive silver halide, at least one of said layers comprising silver haloiodide, and (2) forming differently colored dye images in proportion to said silver images: the improvement which comprises introducing a difiusible 4-thiazoline-2-thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver images, said 4-thiazoline-2- thione having the following general formula:

wherein X represents a substituent selected from the class consisting of alkyl; an alkyl substituent containing at least one hydroxyl group; and, an alkyl substituent having at least one carbonyl-containing group; and, Z represents a substituent selected from the class consisting of hydrogen; alkyl; an alkyl substituent containing at least one hydroxyl group; and, an alkyl substituent containing at least one carbonyl-containing group, whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction.

7. In the process of providing multicolor photographic records which includes (1) developing silver images in an exposed photographic element having at least two superposed hydrophilic colloid layers containing lightsensitive silver halide, at least one of said layers comprising silver haloiodide, and (2) forming differently colored dye images in proportion to said silver images: the improvement which comprises introducing a diffusible 4-thiazoline-2-thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver images, said 4-thiazoline-2- thione being selected from the group consisting of 4-thiazoline-4-carboxaldehyde-Z-thione; 5-carbethoxy-4-methyl-4-thiaZoline-2-thione; 4-carboxy-4-thiazoline-2-thione; 4-carboxy-5-methyl-4-thiazoline-2-thione; 4-carbethoxy-4-thiazoline-2-thione; 4-acetoxymethyl-4-thiazoline-2-thione; 4- (D-arabinotetraacetoxybutyl) -4-thiaZoline-2-thione; 4- (D-glucopenta-acetoxypentyl) -4-thiazoline-2-thione; 4- (D-gluc openta hydroxyp entyl) -4-thiazoline-2-thione; 4-hydroxymethyl-4-thiazoline-2-thione; 4-methyl-4-thiazoline-2-thione; and 4-(D-arabino-l,2,3,4-tetrahydroxybutyl)-4-thiazoline-2- thione,

whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction.

8. In the process for providing multicolor photographic records which includes (1) developing silver image records in an exposed photographic element having coated on a support three superposed hydrophilic colloid layers container light-sensitive silver halide, said layers being selectively sensitive to red, green and blue radiation, which silver images are records for the red, green and blue portions of an object, and (2) forming cyan, magenta and yellow dye images, respectively, in proportion to said red, green and blue silver image records: the improvement which comprises introducing a diffusible 4- thiazoline-Z-thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver image records, whereby undercut interimage effects are obtained for at least one of said dye images.

9. A process of providing multicolor photographic records as defined in claim 8 wherein at least one of said layers comprises light-sensitive silver bromoiodide.

10. A process of providing multicolor photographic records as defined in claim 9 wherein said 4-thiazoline-2- thione has, in the 4-position thereof, an alkyl substituent having a group selected from the class consisting of carbonyl and hydroxyl.

11. A process of providing multicolor photographic records as defined in claim 9 wherein said 4-thiazoline-2- thione contains an alkyl substituents in the 4-position, said alkyl substituent consisting of from 4 to carbon atoms, each of said carbon atoms having a hydroxyl group attached thereto.

12. A process of providing multicolor photographic records as defined in claim 9 wherein said 4-thiazoline-2- thione contains in the 4-position thereof, a substituent selected from the group consisting of formyl, carboxyl, ethoxycarbonyl, hydroxymethyl and acetoxymethyl.

13. In the process for providing multicolor photographic records which includes (1) developing silver image records in an exposed photographic element having coated on a support three superposed hydrophilic colloid layers containing light-sensitive silver halide, said layers being selectively sensitive to red, green and blue radiation, which silver images are records for the red, green and blue portions of an object, and (2) forming cyan, magenta and yelow dye images, respectively, in proportion to said red, green and blue silver image records: the improvement which comprises introducing a diffusible 4-thiazoline-2- thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver image records, whereby undercut interimage effects are obtained for at least one of said dye images, said 4-thiazoline-2-thione having the following general formula:

wherein X represents a substituent selected of the class consisting of alkyl; an akyl substituent containing at least one hydroxy group; and an alkyl substituent having at least one carbonyl-containing group; and, Z represents a substituent selected from the class consisting of hydrogen; alkyl; an alkyl substituent containing at least one hydroxyl group; and, an alkyl substituent containing at least one carbonyl-containing group.

14. In the process for providing multicolor photographic records which includes (1) developing silver image records in an exposed photographic element having coated on a support three superposed hydrophilic colloid layers containing light-sensitive silver halide, said layers being selectively sensitive to red, green and blue radiation, which silver imagw are records for the red, green and blue portions of an object, and (2) forming cyan, magenta and yellow dye images, respectively, in proportion to said red, green and blue silver image records: the improvement which comprises introducing a diffusible 4-thiazoline-2-thione into the exposed photographic element so that the 4-thiazoline-2-thione is present during the development of the silver image records, whereby undercut interimage effects are obtained for at least one of said dye images, which 4-thiazoline-2-thione is selected from the group consisting of 4-thiazoline-4-carboxa1dehyde-2-thione;

5 -carbethoxy-4-methyl-thiazoline-Z-thione;

4-carboxy-4thiazoline-2-thione;

4-carboxy-5-methyl-4-thiazoline-2-thione;

4-carbethoxy-4-thiazoline-2-thi0ne;

4-acetoxymethyl-4-thiazoline-2-thione;

4- (D-arabino-tetraacetoxybutyl) -4-thiazoline-2-thione;

4- D-gluco-penta-acetoxyphenyl) -4-thiazoline-2-thione;

4- (D-gluco-penta-hydroxyphenyl -4-thiazoline-2-thione;

4-hydroxymethyl-4-thiaZoline-2-thione;

4-methyl-4-thiazoline-2-thione; and

4- D-arabinol ,2,3 ,4-tetrahydroxybutyl) -4-thiazo-line- 2-thione.

15. In a complete photographic reversal color process wherein a multilayer photographic element containing a plurality of differentially sensitized photographic silver halide emulsion layers is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image and a second exposure followed by at least one additional development in a photographic developer for producing a color image, the improvement which comprises introducing a diffusible 4-thiazoline-2-thione into said photographic element subsequent to said first exposure so that said 4-thiazoline-2- thione is present during said development which produces silver negative image, whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction.

16. The photographic reversal color process as described in claim 15 wherein at least one of said silver halide emulsion layers comprises silver bromoiodide.

17. The photographic reversal color process as described in claim 16 wherein said silver negative image is developed in the presence of a 4-thiazoline-2-thione which has, in the 4-position thereof, an alkyl substituent having a group selected from the class consisting of carbonyl and hydroxyl.

18. The photographic reversal color process as described in claim 16 wherein said silver negative image is developed in the presence of a 4-thiazoline-2-thione which contains an alkyl substituent in the 4-position, said alkyl substitutent consisting of from 4 to 5 carbon atoms, each of said carbon atoms having a hydroxyl group attached thereto.

19. The photographic reversal color process as described in claim 16 wherein said silver negative image is developed in the presence of a 4-thiazoline-2-thione which contains, in the 4-position thereof, a substituent selected from the group consisting of formyl, carboxyl, ethoxycarbonyl, hydroxymethyl, and acetoxymethyl.

20. In a complete photographic reversal color process wherein a multilayer photographic element containing a plurality of differentially sensitized photographic silver halide emulsion layers is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image and a second exposure followed by at least one additional development in a photographic developer for producing a color image, the improvement which comprises introducing a diffusible 4-thiazoline-2-thione into said photographic element subsequent to said first exposure so that said 4-thiazoline- Z-thione is present during said development which produces silver negative image, whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction, said 4-thiazoline-2-thione having the following general formula:

wherein X represents a substituent selected of the class consisting of alkyl; an alkyl substituent containing at least one hydroxyl group; and an alkyl substituent having at least one carbonyl-containing group; and, Z represents a substituent selected from the class consisting of hydrogen; alkyl; an alkyl substituent containing at least one hydroxyl group; and, an alkyl substituent containing at least one carbonyl-containing group.

21. In a complete photographic reversal color process wherein a multilayer photographic element containing a plurality of differentially sensitized photographic silver halide emulsion layers is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image and a second exposure followed by at least one additional development in a photographic developer for producing a color image, the improvement which comprises introducing a diffusible 4-thiaZoline-2-thione into said photographic element subsequent to said first exposure so that said 4-thiazoline2- thione is present during said development which produces silver negative image whereby undercut effects are obtained for at least one of the dye images in said multicolor photographic reproduction, said 4-thiazoline-2-thione being selected from the group consisting of 4-thiazoline-Z-carboxaldehyde-2-thione; S-car-bethoxy-4-rnethyl-4-thiazoline-2-thione; 4-carboxy-4-thiazoline-Z-thione; 4-carboxy-5-methyl-4-thiaZoline-2-thione; 4-carbethoxy-4-thiazoline-2-thione; 4-acetoxymethyl-4-thiazoline-Z-thione; 4- D-arabino-tetraacetoxybutyl -4-thiazoline-2-thione; 4- D-gluco-penta-acetoxypentyl -4-thiazoline-2-thione; 4- (D-gluco-penta-hydroxypentyl) -4-thiazoline-2-thione; 4-hydroxymethyl-4-thiazoline-2-thione; 4-methyl-4-thiazoline-2-thione; and 4- (D-arabino- 1 ,2,3,4-tetra-hydroxybutyl) -4-thiazoline-2- thione.

22. In a complete photographic reversal color process wherein a multilayer photographic element containing a plurality of differentially sensitized photographic silver halide emulsion layers is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image and a second exposure followed by at least one additional development in a photographic developer for producing a color image, the improvement which comprises introducing a diffusible 4-thiazoline-2-thione into said photographic element subsequent to said first exposure so that said 4-thiazoline-2- thione is present during said development which produces silver negative image, whereby undercut interimage effects are obtained for at least one of the dye images in said multicolor photographic reproduction, said 4-thiazoline-2-thione being 4-(D-arabino 1,2,3,4-tetrahydroxybutyl)-4thiazoline-2-thione.

23. A photographic reversal color process as defined in claim 15 wherein each of said silver halide emulsion layers contains an incorporated color former which produces dye images upon reaction with oxidized primary aromatic color developing agent, and each of said dye images bears a complementary relationship to the region of the spectrum to which the photographic silver halide emulsion has been differentially sensitized.

24. A process of providing multicolor photographic records as defined in claim 1 wherein said diifusible compound is incorporated in the developer used to form said silver images.

25. A process of providing multicolor records as defined in claim 1 wherein said development is conducted at a temperature of from 68 to 180 F.

26. A process of providing multicolor records as defined in claim 6 wherein said development is conducted at about F.

27. A process of providing multicolor records as defined in claim 8 wherein said development is conducted at a temperature of from 68 to F 28. A process of providing multicolor records as defined in claim 13 wherein said development is conducted at a temperature of from 68 to 180 F.

29. A process of providing multicolor records as defined in claim 15 wherein said development is conducted at a temperature of from 68 to 180 F.

30. A process of providing multicolor records as defined in claim 20 wherein said development is conducted at a temperature of from 68 to 180 F.

31. In a complete photographic reversal color process wherein a multilayer photographic element comprising a support having coated thereon a blue sensitive silver bromoiodide emulsion layer containing yellow dye former, a green sensitive silver bromoiodide emulsion layer containing magenta dye former, and a red sensitive layer containing cyan dye former is given a first exposure, followed by development in a photographic developer for producing a black-and-white silver negative image and a second explosure followed by at least one additional development in a photographic primary aromatic amino developing agent to produce dye images: the improvement which comprises incorporating approximately 4.2x 10- moles 4-(D-arabino-1,2,3,4-tetra-hydroxybutyl)-4-thiazoline-2-thione per litre of said developer for producing black-and-white silver negative images.

References Cited FOREIGN PATENTS 7/1934 Great Britain. 9/1939 Germany.

US. Cl. X.R. 9659