USE OF KETOGLUCONATES IN PHOTOGRAPHY

Abstract: Derivatives of ketogluconic acid have been found to be useful as developing agents for photographic media.

Description: USE OF KETOGLUCONATES IN PHOTOGRAPHY The present invention relates to the use of derivatives of ketogluconic acid as photographic agents. Development of a photographic image (both negative and positive) is accomplished by selective reduction of light sensitized silver halide to elemental silver. Chemicals capable of this selective reduction are generally of the "Kendall Structure" X.-(C=C) n -X 2 wherein X, and X 2 are hydroxy, amino or substituted amino group and n is either zero or an integer. Silver halide emulsions are coated on various papers and films for use in photographic applications. When these emulsions have been exposed to radiation, the sensitized emulsion produces a latent image in the silver halide grains. The image is latent because the grains are sensitized to reduction by the formation of minute quantities of free silver in the grains from the exposure. These grains are developed by placing the exposed photosensitive material in an aqueous solution containing one or more specific reducing chemicals. There are very few reducing agents which will only develop the latent image and not reduce the unexposed silver halide. The reducing agents conventionally employed include such organic materials as hydroquinone and other materials meeting the criteria of the Kendall-Pelz rule. The structure of developing agents according to the rule are as follows: a-(A=B)-a' where A is carbon, B is carbon or nitrogen, a and a' are OH, NH 2 , NHR,, NR.R 2 . Examples of chemicals meeting this rule are hydroquinone, catechol, pyrogallol, ascorbic acid and its stereoisomers, and derivatives of phenylenediamine. An example of a developing agent which is an exception to the rule is 1-phenyl-3-pyrazolidone (Phenidone). Two of these developing agents may be used in the same formulation to produce a result known in the photographic industry as superadditivity, also known as synergy. It is defined as the mixture of two developing agents showing a greater degree of developer activity than the sum of the actions of each agent separately. SUBSTITUTE SHEET Figs. 1-6 are graphs showing the effect of various ketogluconates on photographic media. In one embodiment, the present invention is directed to a process for the development of a photographic image on a photographic medium comprising reducing the photosensitized silver on said medium with an effective amount of (a) a compound selected from the group consisting of alkali metal salts, alkaline earth metal salts, amine salts of ketogluconic acid, alkali metal salts, alkaline earth metal salts and amine salts of stereoisomers of ketogluconic acid; and C--C 4 alkyl esters of ketogluconic acid and C,-C 4 alkyl esters of stereoisomers of ketogluconic acid; and (b) a co-developer. In a preferred process, the salt of ketogluconic acid is sodium-2-ketogluconate. In an especially preferred process, the ester is the methyl ester. In another preferred process, the methyl ester is methyl-2-ketogluconate. In another especially preferred process, the alkaline earth metal salt is calcium- 2,5-diketogluconate. In a preferred process, the co-developer is selected from the group consisting of 4-methylaminophenol, 1-phenyl-3-pyrazolidone, and para-phenylenediamines. In a further embodiment, the present invention is directed to a photographic composition comprising (a) an effective amount of a developing agent selected from the group consisting of alkali metal salts, alkaline earth metal salts, amine salts of ketogluconic acid; alkali metal salts, alkaline earth metal salts and amine salts of stereoisomers thereof; C,-C 4 alkyl esters of said salts of ketogluconic acid and stereoisomers thereof; and (b) a co-developer. In a preferred composition the co-developer is selected from the group consisting of 4-methylaminophenol, 1-phenyl-3-pyrazolidone, and para- phenylenediamines. In another embodiment, the present invention is directed to a process for the development of a photographic image on a photographic medium comprising reducing the photosensitized silver on said medium with an effective amount of methyI-2- ketogluconate. In another embodiment, the present invention is directed to a photographic composition containing an effective amount of methyl-2-ketogluconate as a developing agent. SUBSTITUTE SHEET The present invention uses derivatives of ketogluconic acid. These derivatives are used in the form of salts which are hereinafter referred to as either ketogluconates or in the case of the stereoisomers, as ketogulonates. One class of the present developing agents are the alkali metal salts of keto- gluconates, and stereoisomers thereof. The D, L and DL forms of the keto-gluconates may be used. Stereoi s omers of the ketogluconates include the ketogulonates which may also be used in x, ,« D, L or DL forms. Preferred alkali metal salts are the sodium and potassium salts. The sodium and potassium salts of the keto-D-gluconates, keto-L-gluconates, and the k gluconates may be used in the composition and process of the present inver,..υn. Similarly, the sodium and potassium salts of the keto-D-gulonates, keto-L-gulonates and keto-DL-gulonates may be used in the process and compositions of the present invention. Preferred amine salts are the ammonium salts, the triethanolamine saltε, the diethylaminoethyl, cyclohexylamine, and the morpholine salts of the ketogluconates and ketogulonates. Preferred alkaline earth metal salts are the calcium salts of ketogluconates and ketogulonates. As is well known to these skilled in the art to which this invention applies, the derivatives of ketogluconic acid also exist in the diketo form. Thus, as used herein, salts of ketogluconic acid include the diketo salts and esters include the diketo esters. Preferred esters of the ketogluconates and ketogulonates are the C.-C 4 alkyl esters. Preferred is the methyl ester. The derivatives of ketogluconic acid are used with a co-developer. Preferred co- developers are metol (1-phenyl-3 pyrazolidone), a pyrazolidone derivative, phenidone (4-aminomethylphenol), and para-phenylenediamines. Other 3-pyrazolidone silver halide developing agents may be used. Examples of such derivatives include: 1 -p-tolyl-3-pyrazolidone, 5-phenyl-3-pyrazolidone.5-methyl- 3-pyrazoIidone, 1-p-chlorophenol-3-pyrazolidone, 1-phenyl-5-phenyl-3-pyrazolidone, 1- m-tolyl-3-pyrazolidone, 1-phenyl-5-methyl-3-pyrazolidone, 1 -p-tolyl-5-phenyl-3- p f -*olidone, 1 -m-tolyl-3-pyrazolidone, 1-p-methoxyphenyl-3-pyrazolidone s acetamidophenyl-3-pyrazolidone, 1-phenyl-2-acetyl-4, 4-dimethyl-3-pyrazolidone i- phenyl-4, 4-dimethyl-3-pyrazolidone, 1-m-aminophenyl-4-4-propyl-3-pyrazolidone, 1-o- SUBSTITUTE SHEET chlorophenol~4-methyl-4-ethyl-3-pyrazolidone, 1 -m-acetamidophenyl-4, 4-diethyl-3- pyrazolidone, 1 -p-hydroxyphenyl-4, 4-dimethyl-3-pyrazolidone, 1 -p-methoxyphenyl-4, 4- diethyl-3-pyrazolidone, 1 -p-tolyl-4,4-dimethyl-3-pyrazolidone, 1 -p-diphenyl-4,4-dimethyl- 3-pyrazolidone,1 -p-(B-hydroxyethylphenyl)-3-pyrazolidone,1 -o-tolyl-3-pyrazolidone,1 -o- tolyl-4, 4-dimethyl-3-pyrazolidone. Examples of phenylenediamine compounds are N,N-diethyl-p-phenylene- diamine, N,N-diethyl-o-methyl-p-phenylenediamine, N,N-diethyl-methoxy-p- phenylenediamine, P-phenylenediamine, N-ethyl-n-hydroxyethyl-p-phenylenediamine, and N-ethyl-N-hydroxyethyl-o-methyl-p-phenylenediamine. Examples of photographic media on which images may be developed include black and white print film, color transparencies, black and white transparencies, and color print film. It has also been found that the methyl ester of ketogluconic acid, methyl-2- ketogluconate will develop an image without the presence of a co-developer. Thus, the present invention is also directed to a process for developing a photographic image by using methyl-2-ketogluconate as a developer, and to a photographic composition containing methyl-2-ketogluconate as a developing agent. Having described the invention in general terms, reference is now made to specific examples. It is to be understood that these examples are not meant to limit the present invention, the scope of which is determined by the appended claims. The developing formulations used in these procedures are based on universal developer solutions described in the S.P.S.E. Handbook of Photographic Science and Engineering, Wiley, 1973, page 569. Various derivatives of ketogluconic acid were substituted for those described in the formulations. In the test to evaluate the developers on paper, a piece of commercial black and white photographic paper was exposed to a light source from an enlarger at a f-stop of 11 for 30 seconds. A 21 step wedge of various densities was in contact with the paper during exposure. The entire procedure was conducted under safelight conditions. After exposure the paper was developed in the test formulation for 2 minutes. The paper was then placed in an acid stop bath for 10 seconds. Following the stop, the paper was fixed in a Kodak F-5 formulation. The entire development procedure took place in trays placed in a temperature control shaker bath at a constant speed and 20 degree C. The paper was then rinsed in running water for 5 minutes and SUBSTITUTE SHEET dried. The densities of the step wedge developed on the paper were then read on a Macbeth TR 924 densitometer. The results of the test were plotted on a D log E curve. The y axis had the values of densities from the relative step exposure on the x axis. In order to evaluate our developers on film, the exposure and developing of the film took place in total darkness. The film was exposed in a X-Rite 383 sensitometer which has a built in 21 step wedge template. The film was then developed in a test formulation for 4 minutes, stopped for 10 seconds, and fixed (Kodak F-5) for 4 minutes. Again the entire development procedure took place at a constant agitation and a temperature of 20 degree C. The film was then washed in running water for 20 minutes, squeeged, and dried, and a D log E curve was prepared. Example 1 The following formulations were prepared and used to develop Kodak Polycontrast III RC FM paper. gram to 500 ml water sodium sulfite 12.5 12.5 12.5 h ydroquinone 3.0 methyl-2- 10.0 ketogluconate sodium carbonate 15.0 15.0 15.0 SUBSTITUTE SHEET Results of Development The results of this test indicate that methyl-2-ketogluconate is a developing agent and yields equivalent densities to those of hydroquinone and phenidone. The graph of this example is shown as. Fig. 2. Example 2 The following formulations were prepared and used to develop Kodak Tri-X Pan 4164 film. gram to 500 ml water potassium bromide 0.1875 0.1875 0.1875 SUBSTITUTE SHEET Results of Development The results of this test show that methyl-2-ketogluconate has superadditivity with metol, since the sum of the active of the two compounds is greater than either one alone. The graph of the example is shown as Fig. 2. SUBSTITUTE SHEET Example 3 The following formulations were prepared and used to develop Kodak Tri-X Pan 4164 film, grams to 500 ml water 12.5 12.5 12.0 12.0 15.0 15.0 0.125 0.5 0.5 0.5 0.05 Results of Development SUBSTITUTE SHEET The table above shows that methyl-2-ketogluconate is a co-developer with phenidone and displays superadditivity. Phenidone is preferred because it is commercially available in large quantities while other known, related developing agents having similar structures and characteristics are not widely available. The graph of the data is shown as Fig. 3. Example 4 The following formulations were prepared and used to develop Kodak Tri-X Pan 4164 film. The formula for N,N-Diethyl-1 , 4-phenylenediamine will be abbreviated as DEPDA. grams to 500 ml water SUBSTITUTE SHE T Results of Development These results demonstrate superadditivity of methyl-2-ketogluconate with another developing agent. The graph is shown as Fig. 4. Example 5 The following formulation was prepared and used to develop Kodak Polycontrast III RC FM paper. SUBSTITUTE SHEET This data indicates that other ketogluconates can have activity as photographic developers. The graph is shown as Fig. 5. SUBSTITUTE SHEET Example 6 The following formulation was prepared and used to develop Kodak KODALITH Ortho film, Type 3. This data shows that methyl-2-ketogluconate will produce an image on film without co-developers. The graph is shown as Fig. 6. SUBSTITUTE SHEET

Claims: CLAIMS 1. A process for the development of a photographic image on a photographic medium comprising reducing the photosensitized silver on said medium with an effective amount of (a) a compound selected from the group consisting of alkali metal salts, alkaline earth metal salts, and, amine salts of ketogluconic acid; alkali metal salts, alkaline earth metal salts, and, amine salts of stereoisomers of ketogluconic acid, and C,-C 4 alkyl esters of ketogluconic acid, C,-C 4 alkyl esters of stereoisomers of ketogluconic adid, and (b) a co-developer for said photographic medium. 2. A process according to claim 1 wherein said salt of keto-gluconic acid is sodium 2-ketogluconate. 3. A process according to claim 1 wherein said ester is the methyl ester. 4. A process according to claim 3 wherein said methyl ester is methyl 2- ketogluconate. 5. A process according to claim 1 wherein said alkaline earth metal salt is calcium-2,5-diketogluconate. 6. A process according to claim 7 wherein said co-developer is selected from the group consisting of methylaminophenol, 1-phenyl-3-pyrazolidone and para- phenylenediamines. 7. A photographic composition containing an effective amount of a developing agent selected from the group consisting of alkali metal salts, alkaline earth metal salts, amine salts of ketogluconic acid; alkali metal salts, alkaline earth metal salts and amine salts of stereoisomers thereof; C,-C 4 alkyl esters of ketogluconic acid, and C,-C 4 alkyl esters of stereoisomers of ketogluconic acids, and (b) a co-developer in said photographic medium. 8. A composition according to claim 7 where said co-developer is selected from the group consisting of methylaminophenol, 1-phenyl-3-pyrazolidone and para- phenylenediamines. 9. A process for the development of a photographic image on a photographic medium comprising reducing the photosensitized silver on said medium with an effective amount of methyl-2-ketogluconate. 10. A photographic composition containing an effective amount of methyl-2- ketogluconate as a developing agent. SUBSTITUTE SHEET

Inventors: GEWANTER HERMAN L, RASHAN JOSEPH M JR, REITZ LARRY R, GEWANTER, HERMAN, L., RASHAN, JOSEPH, M., JR., REITZ, LARRY, R.
Applicants: PFIZER, PFIZER INC.
Application year: 1993
Main classification: G03C5
IPC codes: G03C5