US2566180A

US2566180A - Direct postive photogrpahic color process

Info

Publication number: US2566180A
Application number: US44214A
Authority: US
Inventors: Fallesen George Earle; Stauffer Robert Eliot
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1948-08-13
Filing date: 1948-08-13
Publication date: 1951-08-28
Anticipated expiration: 1968-08-28
Also published as: BE490657A; FR1001737A

Description

1951 GE. FALLESEN EIAL 2,566,180

DIRECT POSITIVE. PHOTOGRAPHIC cdLoR PROCESS Filed Aug. 13. 1948 EXPOSURE INTERNAL mmvr/maz F] G. 1. 1 TREATMENT 04 com)? DEVELOPER aw: arm/11v: INH'RN/ll. EMULSION 22 q rc'uow FILTER 2o g}- GREENSEM'IT/Vf INTERNAL EMULSION FIG. 2. RED SENSITIVE INTERN/IL EMULSION GEORGE E.FALLESEN ROBERT E. STAUFT'ER INk'jNTQRS M ATTORNEYS Patented Aug. 28, 1951 UNITED STATES PATENT OFFICE Rochester, N. Y., assignors to Eastman Kodak Company, Rchester, N. Y., a corporation of New Jersey ApplicationAugus't 13, 1948, Serial No. 445214 3'C1aims. I This invention relates to photography and particularly to a method of making direct positive color photographs.

Fallesen U. S. application Ser. No 780,405, filed October 17, 1947, now U. S. Patent 2,497,875,

granted February 21, 1950, describes a process of making direct positive photographs in which a special type of silver halide emulsion capable of giving an internal latent image is exposed and developed in a photographic developer which is capable of giving aerial fog. Exposure of this emulsion produces an internal latent image and development of the exposed emulsion in a developer which gives aerial fog, develops a positive image inthose regions of the emulsion layer which were not exposed. Stauffer U. S. application Ser. No. 780,569, filed October 17, 1847, now U. S. Patent 2,497,817, granted February 21, 1950,. describes a method for obtaining increased aerial fog and higher maximum density of, the reversal image in the Fallesen process by the addition to the developer of certain compounds such as benzotriazole which are so constituted as to increase the maximum density of the positive image obtained in developing solutions capable of producing aerial fog.

Glass and Richey, as described in their U. S. application Serial No. 780,574; filed October 17, 1947,. now U. S. Patent 2,507,154, granted May 9, 1950, found that the aerial fogging developer of Fallesen could be replaced with a developer containing a primary aromatic amino developing agent and an active methylene coupler compound to form positive silver and dye images. In the Glass and Richey process the formation of the dye image is incidental to the formation of the silver image, since not all color couplers produce the reversal obtained with the active methylene coupler compounds. Couplers of the naphtholic or phenolic type are not operative in a the Glass and Richey process. Therefore, while yellow and magenta dye images can be obtained in the Glass and Richey process cyan images 1 have not been obtained and the process has limited utility in the field of color photography.

Ives described, in U. S. application Serial No.

capable of developing the surface latent image.

Since the processes described above are not capable of producing a range of colors suitable for natural color photography, it is the primary purpose of our invention to provide a method for the production of naturalcolor images, that is, a methodwhich will permit the formation of direct positive color photographs having a full range ofcolors.

This object is accomplished according to our invention by following a two-bath procedure similar to that of the Ives application'S'erial No. 780,318, now Patent No. 2. 333 oh We expose a suitable single layer or multidayer emulsion to an image, treat the exposedmaterial for a short time in a developer capable of producing surface latent ima e in the unexposed regions and then treat the exposed material in a developing solution containing a primary aromatic amino developer. To produce a color image, there must be a color coupler either in the developer or in the emulsion layer and either method can be used according to our invention.

In the accompanying drawing, sectional views of a photographic element at successive stages in our process are shown.

The photographic emulsion used in the process of our invention is a gelatino-silver halide emulsion such as silver bromide, silver bromoiodide or silver chloroiodide emulsion. It need not contain optical sensitizing dyes although certain sensitizing dyes may be added to it for the purpose of inducing aerial l'o'g, as well as for optical sensitizing The emulsion should be undigested or if digested, the digestion should be carried out without the use of surface sensitizers. An emulsion of this type isknown as Burtons Emulsion described in Wall Photographic Emulsions, 1927, pages 52 and 53. A further type of emulsion suitable for our process is an internal latent image emulsion described in Davey and Knott U. 3. application Ser. No. 790,232, filed December 6, 1947, now abandoned, of which application Serial No. 82,914, filed March 22, 1949, is a continuation-in-part.

Most of the internal latent imagetemulsions are silver bromoiodide of high iodide content, preferably containing at least 10 to 20% of the amount of silver halide as the iodide. Burtons Emulsion is an emulsion of. this type having a silver iodide content ofapproximately 40% of the content of silver halide. It is not absolutely essential, however, for the emulsion to contain silver iodide.

An internal latent image type of silver hal- 3 ide emulsion may be defined as one which, when a test portion is exposed to a light intensity scale for a fixed time between ,5 and 1 second and developed for 4 minutes at 20 C. in the ordinary surface developer (Example 1), exhibits a maximum density'not greater than the maximum density obtained when the same emulsion is equally exposed and developed. for 3 minutes at 20 C. in an internal type developer (Example 2). Preferably the maximum density ob= tained with the surface developer is not great-= er than 1 6 the maximum density obtained when the same emulsion is developed in the internal type developer. Stated conversely, an internal latent image emulsion, when developed in an internal type developer (Example 2) exhibits a maximum density at least and preferably at least 10 times the maximum density obtained when the emulsion is exposed in the same way and developed in a surface developer (Exam= ple 1).

According to our method of producing direct positive color images, an emulsion of the type described above is exposed to light rays or to a suitable image and is then bathed for approximately seconds to 1 minute in a selectively fogging developer such as those described in Fallesen U. S. Patent 2,497,875, Stauifer U. S. Patent 2,497,817 or Glass and Bichey U. S. Patent 2,507,154. After a brief rinse, the film is placed in an active developer containing a primary aromatic amino developing agent and a color coupler, unless the color coupler is present in the emulsion layer. Color couplers of the proper constitution can be introduced into the emulsion layers either in the form of coupler-= solvent dispersions as described in Marines and Godowsky U. S. Patent 2,304,940 or Jelley and Vittum U. S. 2,322,027 or as non-wondering coupiers of the type described in Fischer U. S. Patent 1,102,028. About ten minutes are generally required to produce the color image, although a shorter time may be sufficient. If the film is allowed to remain in the selectively fogging developer for about 12 to 15 minutes, a positive silver image will be formed. On the other hand, if the film is placed in the color developing solution without being placed in the fogging developing solution, a negative dye image will be produced in some cases and a positive dye image in others. If the color couplers used in the developer are of the type described in Glass and Richey U. S. Patent 2,507,154, a positive dye image will be produced and if the couplers are of the phenolic or naphtholic type, a negative dye image will be produced.

In the short treatment in the selective fogging developer used in our invention, no visible image appears in the emulsion. The treatment is mainly one of preparation and conditioning for subsequent development. Presumably the selectively fogging developer creates development centers on the surface of the silver halide grains and these are more susceptible to development in the active surface type developer used in the second step, than the development centers created inside the grains by the action of the earlier light exposure. When the emulsion is subjected to treatment in the selectively fogging developer, the grains aifected by the light 6X posure are less susceptible to development in the active surface type developer used in the second step, than the development centers created inside the grains by the action of earlier light exposure. When the emulsion is subjected to the internal latent image type is exposed to light under an image represented as having a transparent portion [2 and an opaque portion l3. This exposure produces an internal latent image at 14 in the emulsion layer I l.

, Treatment of the exposed element in the selectively fogging developer produces a surface latent image at [5 in the portions of the layers which were not exposed without affecting the internal latent image at 14 as shown in the second stage of the drawing.

A treatment of the element in an active color developer reduces the surface latent image to a metallic silver and dye image it as shown in the third stage of the drawing. The remaining silver halide and metallic silver are then removed to leave the dye image I! in the portions of the layer which were unexposed by the original exposure as shown in the final stage of Fig. l of the drawing.

Fig. 2 of the drawing illustrates a multi-layer material having a support [3 with superposed emulsion layers [9, 20 and 2! coated thereon. Emulsion layer I9 is a red-sensitive internal latent image emulsion containing a color coupler capable of forming a cyan dye image. Emulsion layer 20 is a green-sensitive internal latent image emulsion containing color coupler capable of producing a magenta dye image. Emulsion layer 2| is a blue-sensitive internal latent image emulsion containing a color coupler capable of producing a yellow dye image. The usual yellow filter layer 22 is present between emulsion layers 20 and 2| to prevent blue light from exposing emulsion layers l9 and 20.

An ordinary surface type developer, that is, one which develops an image only on the surface 'of the grains of an internal latent image emulsion is the following.

Example 1 p-Hydroxyphenylglycine grams 10- Sodium canbonate, (crystals) -do Water to liter 1 Development time, 4 min. at 20 C.

An internal type developer, that is, one which develops an image inside the grains of an :internal latent image emulsion is the following:

Example 2 Hydroquinone grams 15 Monomethyl-p-aminophenol sulfate do 15 Sodium sulfite (anhyd) do 50 Potassium bromide do 10 Sodium hydroxide do 25 Sodium thiosulfate (crystals) do 20 Water to liter 1 Development time, 3 min. at 20 C.

A developer which produces a direct positive image on exposure and development of an internal latent image emulsion as described in axiom-e Active color developers which" may be used to fogging developer are as follows:

Example 4 p-Amino diethylanillne HCI grams 2 Sodium sulfite (des.).-- -i dor i 2 Sodium carbonate (anhyd) do 20 2,4-dichloro-l-naphthol -do 3 Sodium hydroxide do 3 Water to 1iter 1 Example 5 ip-Amino diethylanilirle FZCl grams 2 Sodium 'sulfite (des.) do 2 Sodium carbonate (anhyd) i do 20 JAcetoacet-2,5-dichloro .anilide Minded 3 Sodium hydroxide headerv3 Water to s -i-- e liter 1 Eframple 6 p-Amino diethylaniline HCl grams 2 Sodium sulfite (des.) do 2 Sodium carbonate (anhyd) do 20 p-Nitrophenyl acetonitrile do 3 :Sodiiiin hydroxide do 3 Water to an. i r liter 1 In place of the couplers described above, any of the customary color-forming compounds may be used.

Our invention will now be described by reference to the following specific example.

An emulsion such as that described in Davey and Knott U. S. application 790,232 was coated on a support, dried and exposed on an Eastman IIb Sensitometer (Jour. Soc. Motion Picture Engineers, vol. 17, 1931, page 536). The exposed film was bathed for 15 seconds at 68 F. in the developer of Example 3 in a shallow tray and after a '5-second rinse in running water was placed immediately in a tank containing one of the developers of Examples i, 5 and 6 for a period of 10 minutes at 68 F. The three developers produced, respectively, silver and cyan, silver and yellow, and silver and magenta dye images. The silver images were then bleached in the usual way and the undeveloped silver salts fixed out to leave dye images in the gelatin.

To prepare a multi-layer natural color dye image, a support was coated with successive layers of red-sensitive emulsion, green-sensitive emulsion, yellow filter and blue-sensitive emulsion, all emulsions being of the type described in Davey and Knott U. S. application 790,232. The red-sensitive emulsion contained 5-(p-amyl phenoxy benzene sulfonamino-l-naphthol), the green-sensitive contained 2-cyano-acetyl-5-(psec. amyl benzoylamino) coumarone and the blue-sensitive contained N amyl-p-benzoyl ace- .tamino benzene sulfonate. All couplers were dispersed in the emulsions as described in Jelley and Vittum U. S. Patent 2,822,027, granted June 15, 1943.

The emulsions were exposed to a step tablet 6, andwere'then developed for 15 minutes in L be following developer (Example 7): i

.Cyan;magenta, andyellow dye images were pro- 'ducedin the red-sensitive, green-sensitive and .blue sensitive layers, respectively, and the silver was" then converted toasoluble salt and removed by fixing inthe usual way.

It will be understood that the modifications included herein are illustrative only and that variations may be made incur process within, the

scope of the appended claims.

Weclaim: 1. The method oiuobtaining a direct positive :dye image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer a test portion of which upon exposure to 'a light intensity scalefor a fixed time between ,I/lOO'and 1 second andidevelopment for 3 minutes at 20.C.'in thefollowing internal type de veloper:

Hydroquinone grams" l5 Monornethyl p-a1nino1: henol sulfate- .do '15 Anhydrous sodiumsuliite s do 50 Potassiumbromide do 10 Sodium hydroxide do. 25 Sodiumthiosulfate 1do 20 Water to liter 1 1 gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface de= veloper (I):

p-Hydroxyphenylglycine grams 10 Sodium carbonate (crystals) do Water to liter" 1 immersing the exposed emulsion layer in an aerial fogging developer for about 15 seconds to l min ute, during which time no visible image is formed, then immersing said layer in an active surfacetype developer containing a primary aromatic amino developing agent and a color coupler, for approximately 10 minutes during which time a positive dye image is formed in said layer.

2. The method of obtaining a direct positive dye image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer a test portion of which upon exposure to a light intensity scale for a fixed time between 1/100 and 1 second and development for 3 minutes at 20 C. in the following internal type developer:

Hydroquinone grams 15 Monomethyl-p-aminophenol sulfate do 15 Anhydrous sodium sulfite do. 50 Potassium bromide do 10 Sodium hydroxide do 25 Sodium thiosulfate do 20 Water to liter -1 gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 7 minutes at 20 C. in the following surface developer (I) p-Hydroxyphenylglycine grams Sodium carbonate (crystals) do 100 Water to liter 1 immersing the exposed layer in an aerial fogging developer of the following composition for about seconds at 68 F.:

Hydroquinone grams 10 Sodium sulflte (des.) do 16 p-Formalydehyde do 4 Sodium carbonate (anhyd.) do Benzotriazole do 0.4 Water to liter 1 then immersing said layer in an active surfacetype developer containing a primary aromatic amino developing agent and a color coupler, for

7 approximately 10 minutes during which time a veloper:

Hydroquinone grams" 15 Monomethylp-aminophenol sulfate do 15 Anhydrous sodium sulfite do 50 Potassium bromide do 10 Sodium hydroxide do 25 Sodium thiosulfate do 20 Water to liter 1 gives a maximum density at least 5 times the 8 maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface developer (I):

p-Hydroxyphenylglycine grams 10 Sodium carbonate (crystals) do Water to liter 1 immersing the exposed layer in an aerial fogging developer of the following composition for about 15 seconds at 68 F.:

Hydroquinone grams 10 Sodium sulflte (des.) do 16 p-Formaldehyde do 4 Sodium carbonate (anhyd) do 25 Benzotriazole (10.... 0A Water to liter 1 then immediately immersing said layer in the following active developer for about 10 minutes at 68 F.:

p-Amino-diethylaniline HCi grams 2 Sodium sulflte (des.) do 2 Sodium carbonate (anhyd) do 20 p-Nitrophenyl acetonitrile do 3 Sodium hydroxide do 3 Water to liter 1 thereby forming a positive magenta dye image in said layer.

GEORGE EARLE FALLESEN. ROBERT ELIOT STAUFFER.

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

Wall: Photographic Emulsions," publ. 1929 by Amer. PhQt-.l?ub1. Co., Boston; pages 52 and, 5.3..

Claims

1. THE METHOD OF OBTAINING A DIRECT POSITIVE DYE IMAGE IN SILVER HALIDE EMULSION LAYER, WHICH COMPRISES EXPOSING TO LIGHT RAYS TO WHICH THE EMULSION IS SENSITIVE, A SILVER HALIDE EMULSION LAYER A TEST PORTION OF WHICH UPON EXPOSURE TO A LIGHT INTENSITY SCALE FOR A FIXED TIME BETWEEN 1/100 PART AND 1 SECOND AND DEVELOPMENT FOR 3 MINUTES AT 20* C. IN THE FOLLOWING INTERNAL TYPE DEVELOPER: