US2178450A - Developing photographic films and plates - Google Patents

Description

Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE DEVELOPING PHOTOGRAPHIC FILMS AND PLATES poration of Delaware No Drawing. Application April 6, 1938, Serial No. 200,432

16 Claims.

This invention relates to photographic developers and methods of photographic developmg.

Photographic development, particularly of films, has been subject to a number of difliculties such as the formation of air bubbles on the emulsion, pin hole formation and uneven development, particularly when a rapid developer is used in a day-light developing tank where the solution is poured in and one portion of the film encounters the developer before other portions. These difficulties are largely due to high surface tension of the developer solution. However, the ordinary type of surface tension reducing materials such as for example ordinary soaps and the like cannot be used because they are not inert in the process.

According to the present invention, the distribution of the developer solution over the surface of the photographic emulsion is effected by the presence of minute amounts of salts of esters of aliphatic sulpho dicarboxylic acids. Among the compounds which may be used are salts of the esters of sulphosuccinic, sulphomaleic, sulphoglutaric and other sulpho dicarboxylic acids. The esters may be of various alcohols depending ,on the particular acid used. In general, the molecular weight of the alcohols should be greater with sulpho dicarboxylic acids of low molecular weight and may be less with those of higher molecular weight. Taking the esters of sulphosuccinic acid as an example, because they are commercially available, the effectiveness is much lower with the methyl, ethyl, propyl and butyl esters and increases rapidly until the octyl ester is reached, beyond which the effectiveness slowly decreases. We have found that the best material for the present invention is sodium dioctyl sulphosuccinate which is extremely effective.

The sulpho dicarboxylic acid esters of the present invention have the important property that they do not form decomposition products, which exert any deleterious action on development. This is an important factor because on long standing, particularly with developers of high pH, a considerable degree of decomposition of the sulpho dicarboxylic ester takes place.

The present invention may be carried .out by two general methods suitable for diiferent types of developing technique. The simplest method for tray development for plates, film packs, cut film and the like is to subject the material to a preliminary bath in a very dilute aqueous solution of the sulpho dicarboxylic ester. The wetted film is then transferred to the developer and developed, hardened and fixed in the usual manner. No change in operating technique is required and the advantages of complete freedom from pin holes, streaks and other evidences of uneven development are obtained withoutany sacrifice irr emulsion speed, definition, grain size or other desirable characteristics of a particular developer or a development technique. When desensitization is employed, the desensitizer such as pinacryptol yellow or green may be added to the preliminary bath in which case, of course, the film or plate should be left in the preliminary bath for a suflicient time to satisfactorily desensitize, which in general will be longer than the time required to thoroughly distribute a film of the dilute solution of the sulpho dicarboxylic ester over the photographic emulsion. It is an advantage of the present invention that the emulsion is not in any way aifected by long contact with the sulpho dicarboxylic ester.

The second method which is more satisfactory for tank development, particularly in the daylight tanks where solutions are added in full daylight, and in the development of prints, involves the addition of a small amount of sulpho dicarboxylic ester to the developer. This eliminates the necessity of a separate bath but is not universally applicable to alltypes of developers as will be pointed out below.

Salts of sulpho dicarboxylic acid esters such as sodium dioctyl sulphosuccinate are sensitive to alkali and at high pH values are destroyed to a considerable extent. Thus, with developers of very high pH such as D-72 and particularly D-ll, D-9 and other high energy developers, the effectiveness of the sulpho dicarboxylic ester decreases after standing for days and weeks. With developers of lower pH such as D-76, DK-50, Sease #3, Champlin #15 and the like, the effectiveness of the sulpho dicarboxylic ester remains for many weeks and even months. In the case of developers having a pH of about 53.8-10.0, there is considerable decomposition of the sulpho dicarboxylic ester when standing for weeks. Typical examples of such developers are D-16, and the Agfa Tropical developer. Even in the case of these developers, the effectiveness of the sulpho dicarboxylic ester remains for a considerable period of time. i The second method, that is to say where the sulpho dicarboxylic ester is incorporated with the developer and not as a separate bath, may also be used even with developers of very high pH in which case a small amount of the sulpho dicarboxylic ester is added to the developer just before it is used. The decomposition products do not harm development and fresh additions maybe -made each time the developer is used.

In the case of print development, which usually employs developers such'as D-72 having a pH of somewhat over 10.0, the sulpho dicarboxylic ester is added to the diluted developer and it is not material that the resulting product does not keep very well since a batch of diluted developer is discarded after an evenings. printing in any event. The addition of the sulpho dicarboxylic ester to a strong stock solution of D-72 is not desirable as it decomposes and loses its activity within a few weeks.

The choice of the particular method of employing the present invention will be determined to a large extent by the pH of the developer. In the case of sodium dioctyl sulphosuccinate, the preferred sulpho dicarboxylic ester of the present invention. the critical pH range is somewhere around 9.8. Developers with lower pHs such as D-76, Sease #3, Champlin #15 and the like show excellent keeping qualities and therefore it is preferable to incorporate the dioctyl sulphosuccinate with these developers. Developers of higher pH are preferably used with a preliminary bath.

The following examples will illustrate the invention.

Example 1 A bath is prepared containing about 0.25% of sodium dioctyl sulphosuccinate. The films or plates to be developed are immersed for a short time in the bath, then if desired rinsed in a bath of plain water and developed in the usual manner. Complete freedom from streaks, pin holes and other results of uneven development will be noted. No streaking will occur even though a developer of high speed, such as D-72, is employed and even though but little agitation is used.

For convenience, it is desirable to make up a 2% stock solution of the sodium dioctyl sulphosuccinate which is most advantageously made in an 80% water, 20% methyl alcohol solution. A small portion of the stock solution is diluted with water to make up the 0.25% bath.

If desired, desensitization can be effected by incorporating a desensitizer in the bath containing the sodium dioctyl sulphosuccinate or in a bath following it. Desensitization is more rapid and complete because of the action of the sodium dioctyl sulphosuccinate.

Example 2 D-"76 developer is prepared in accordance with the standard formula published by the Eastman Kodak Company containing 2 gms. of metol, 5 gms. of hydroquinone, 100 gms. of anhydrous sodium sulfite and 2 gms. oi borax per liter of water. 1 cc. of a 10% aqueous solution of sodium dioctyl sulphosuccinate is added and the developer used in the normal manner. For example, in developing a roll of mm. Eastman Supersensitive Panchromatic film, the film is loaded into a day-light tank, the lights turned on, the developer added and development continued for 15 minutes with only occasional agitation. An excellent negative is obtained free from any evidence of uneven development and the results are in every way comparable to those obtained by continuous agitation, it being an advantage of the present invention that practically stagnant development can be used without uneven results. On standing for weeks, no substantial change in the developer solution is noted and it can be reused to the same extent as ordinary D-76 developer.

Example 3 A Sease #3 developer containing 10 gms. of pphenylenediamine, 6 gms. of glycine and 90 gms. of anhydrous sodium sulfite to the liter of water is prepared and 0.75 cc. of a 10% solution or sodium dioctyl sulphosuccinate is added. Tank development of 35 mm. Eastman Supersensitive Panchromatic film is carried out as described in Example 1, the development time being 27 minutes at 21 C. The development is stagnant and a negative is obtained free from any signs of uneven development.

The developer maintains its desirable properties even on standing for weeks.

Example 4 A Champlin #15 developer containing 3.5 gms. of pyrogallol, gms. of anhydrous sodium sulfite, 1.2 gms. of benzoic acid, 0.5 gms. of salicylic acid, 2.5 gms. of boric acid, 1 gm. of digallic acid, 11.5 gms. of glycine, 11.5 gms. of p-phenylenediamine, 50 cc. of isopropyl alcohol and 1 gm. of nickel ammonium sulfate in a liter of water is mixed with 1 cc. of a 10% aqueous solution of sodium dioctyl sulphosuccinate. stagnant tank development of 35 mm. rolls of Eastman Supersensitive Panchromatic film carried out for 27 minutes at 21 C. results in a negative of excellent characteristics showing no trace of uneven development. The developer retains its characteristics on standing for weeks.

Example 5 An Agia Tropical developer containing 2.5 gms. of metol, 18 gms. of anhydrous sodium sulfite, 6.5 gms. of hydroquinone, 16 gms. of anhydrous sodium carbonate and 1 gm. of potassium bromide in a liter of water is mixed with 1 cc. of 10% aqueous solution of sodium dioctyl sulphosuccinate. A cut film of Eastman Supersensitive Panchromatic film is developed in a tray with full agitation for one and a half minutes at 29 C. The film is then hardened with chrome alum hardener and fixed in the usual manner for tropical development. No sign of uneven development is to be noted which is particularly important as the high speed of the developer makes streaking due to non-uniform development more serious than in slower developers.

The developer shows considerable loss of characteristics after standing for several weeks and if permitted to stand for so long a time, a small amount, for example 0.5 cc., of 10% sodium dioctyl sulphosuccinate should be added before reuse. 1

Example 6 An Eastman D-16 developer is prepared containing 0.31 gm. of metol, 6 gms. of hydroquinone, 39.6 gms. of anhydrous sodium sulfite, 18.7 gms. of anhydrous sodium carbonate, 0.86 gm. of potassium bromide, 0.68 gm. of citric acid and 1.5 gms. of potassium meta-bisulfite in a liter of water. 2 cc. of a 10% solution of sodium dioctyl sulphosuccinate is added and orthochromatic process film developed in a tray with full agitation for three minutes at 18 C. An excellent negative is obtained with no traces of uneven development.

The developer loses but little of its characteristics on standing for several weeks.

Example 7 A 13-72 developer for print development is prepared by diluting D-72 stock solution containing 3.1 gms. of metol, 12 gms. of hydroquinone, 45 gms. of anhydrous sodium sulfite, 67.5 gms. of anhydrous sodium carbonate and 1.9 gms. of potassium bromide to the liter of water with 3 to 4 parts of water and adding from 0.2 to 0.3 cc. of 10% solution of sodium dioctyl sulphosuccinate to the liter of diluted solution. Paper developed in this developer gives excellent prints with no ment is to be noted in spite of the stagnant tank development. The developer will keep for a day or two but will not keep for a longer period of time and should be discarded after use.

Example 8 A developer of the formula of Eastman Kodaks DK-50 is prepared and 1 cc. of a 10% aqueous solution of sodium di(methy1 amyl) sulphosuccinic acid is incorporated. A roll of 2%" by 3 Agfa Superplenachrome roll film is loaded into a day-light developing tank and 500 cc. of the dedeveloper poured into the tank without agitation. Substantially stagnant development is then carried out for five minutes at 18 C. and the negative then fixed and hardened in the customary manner. The negative shows excellent detail with no sign of uneven development in spite of the relatively slow addition'of the developing solution which would normally result in a streaked roll because of longer development of the portion of the roll in the bottom of the tank.

The developer keeps satisfactorily for weeks but if kept for more than a month requires the addition of fresh sulphosuccinic ester.

The examples give typical results obtainable by means of the present invention with standard developers. It is an advantage of the invention that it is equally applicable to all types of films having been successfully used not only on Supersensitive Panchromatic, high speed Orthochromatic and slow speed Orthochromatic films as described above but also on slow speed panchromatic and motion picture positive. In the case of process films and motion picture positive films where high contrast developers of high pH are often used, the invention gives exceptionally good results because these high energy developers tend toward uneven development due to their high developing speed.

What we claim is:

1. A method ofdeveloping silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a chemical developer together with an effective amount not substantially exceeding 0.25% of a salt of an ester of an aliphatic sulfodicarboxylic acid.

2. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a bath consisting of an aqueous solution containnig an effective amount not substantially exceeding 0.25% of a salt of an ester of an aliphatic suliodicarboxyllc acid and then subjecting the emulsion to the action of a photographic developing agent.

3. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a photographic developing solution having incorporated therein an effective amount not substans tially exceeding 0.25% of a salt of an ester of an aliphatic sulfodicarboxyllc acid.

4. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a chemical developer together with an effective amount not substantially exceeding 0.25% of a salt of an ester of sulfosuccinic acid.

5. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to. the action of a bath consisting of an aqueous solution containing an efiective amount not substantially exceeding 0.25% of a salt of an ester of sulfosuccinic acid and then subjecting the emulsion to the action of a photographic developing agent.

6. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a photographic developing solution having incorporated therein an eiiective amount not substantially exceeding 0.25% of a salt of an ester of sulfosuccinic acid. I

'7. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a chemical developer together with an efiective amount not substantially exceeding 0.25% of a salt of a dioctyl ester of sulfosuccinic acid.

8. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a bath consisting of an aqueous solution containing an effective amount not substantially exceeding 0.25% of a salt of a dioctyl ester of sulfosuccinic acid and then subjecting the emulsion to the action of a photographic developing agent.

9. A method of developing silver halide emulsions which comprises subjecting the emulsion containing a latent image to the action of a photographic developing solution having incorporated therein an effective amount not substantially exceeding 0.25% of a salt of a dioctyl ester of sulfosuccinic acid.

10. A photographic developing solution having incorporated therein an effective amount not substantially exceeding 0.25% of a salt of an ester of an aliphatic sulfodicarboxylic acid.

11. A photographic developing solution having incorporated therein an efiective amount not substantially exceeding 0.25% of a salt of an ester of sulfosuccinic acid.

12. A photographic developing solution having incorporated therein an efiective amount not substantially exceeding 0.25% of a salt of a dioctyl ester of sulfosuccinic acid.

13. A method according to claim 3 in which the amount of the salt of an aliphatic sulfo dicarboxylic acid ester does not exceed 0.01%.

14. A photographic developer solution according to claim 10 in which the concentration of the salt of an aliphatic sulfo dicarboxylic acid ester is of the order of magnitude of-0.01%.

muons o. Janeen. JOSEPH n. JEWETT.