US2550617A - Fine grain photographic developer containing morpholine - Google Patents

Description

Patented Apr. 24, 1951 FINE GRAIN PHOTOGRAPHIC DEVELOPER CONTAINING MORPHOLINE George L. Steans, New York, N. Y., assignor to a The FE Corporation, New York, N. Y., a corporation of New York No Drawing. Application June 6, 1946, Serial No. 674,939

1 Claim.

My invention relates generally to the art of photography, and in particular it relates to developers, that is, solutions for developing latent images on photographic film having a silver tween 8.2 and 9. I have found that this pH range and the resultant very fine grain obtained with my developer to be due largely to the presence of the mcrpholine in the solution, and that the halide emulsion thereon, after exposure of the 5 grain size is measurably increased when other film to the action of light. alkaline compounds are used instead.

Most developers, or developing solutions, com- An illustrative example of a very fine grain prise a developing agent as metol (paramethyldeveloper compounded in accordance with my aminophenol sulphate), a preservative as sodium invention is as follows:

sulfite, an accelerator as sodium carbonate, and a restrainer as potassium bromide. Silver halide Metol (paramethylaminophenol solvents, as sodium thiocyanate, are also added Sulphate) 6 in certain instances, for decreasing the size of the sodmm Sumte 80 silver grains. While these developers are relasodmn} thlocya'r late 1 tively satisfactory for'larger film sizes where the -P bromlde Morphohne "cc" 1 enlargement factor is relatively small, I have dis covered that they can be very much improved not only for use with films of smaller size, as 35 mm., but also for the larger film sizes, by the substitution in the solution for the alkalies now used of an alkaline compound containing a secondary amine and an ether group, the compound being known as morpholine of the following formula:

Water to make one liter of solution.

I believe that the foregoing example is the very first disclosure of a practical and highly beneficial metol-containing developing compound using morpholine itself. The morpholine aids in maintaining the alkalinity of the solution, and has a very noticeable effect on the keeping properties thereof when used in concentrations described,

OH CHz 0 NH for it permits the use and re-use of the developer over a much longer period of time than heretofore 2 2 possible with standard or ordinary developers Among the objects of my invention, therefore, are the formation of an extremely fine grain developer for silver halide emulsion films which has longer keeping qualities than previously known developers and which maintains its alkalinity over a longer period-of time than heretofore possible, by means of the addition to the solution of morpholine. Other objects of my invention will be obvious from the following description of an illustrative embodiment, and still others will be specifically pointed out in the following description.

Developers including those containing metolhydroquinone are already known in the art which use derivatives of morpholine, or which use reaction products of morpholine and sulphur dioxide, and which use sulfites of morphcline, but none of these have the properties of my new and improved developer, and none of these prior diswhich do not contain morpholine.

I have found, further, that morpholine may advantageously be added to the metol-containing developing solution as above described in concentrations of between .15 cc. to 3 cc. per liter, which corresponds to 315% to 3% by volume, the resultant solution achieving and retaining all the benefits above described. As used herein, and in the claim appended hereto, the term metol refers to the product commercially and commonly known as p-aramethylaminophenol sul phate.

Having described my invention, what I claim and desire to secure by Letters Patent is:

A photographic developer essentially consisting of an aqueous solution of the following ingredients in approximately the amounts indicated per liter of solution:

closures evidence any appreciation of the benefits Paramethylaminophenol sulphate grams 6 attendant the use of morpholine in the developsodium s lfite do 8O SOIU-tiOIIJ Sodium thiocyanate do 1 r This particular compound, morpholine, has otassium bromide do .7 some developing properties of its own, and. when M honn cc. 1 used as an alkaline agent in connection with metol-containing developing compounds, con- GEORGE L. STEANS. taining preservatives, silver halide solvents and restrainers, my compound has a final pH of be- (References on following page) REFERENCES CITED UNITED STATES PATENTS Number FOREIGN PATENTS Country Date Great Britain June 27, 1935 OTHER REFERENCES Number Name Date Monthly Abstract Bulletin, published by Peterson Apr. 9, 1940 Eastman Kodak 00., Rochester, New York, vol. Wood Apr. 16, 1940 26 (1940), page 19.

Wood Apr. 16, 1940 Henney: Handbook of Photography, 1939, Schneider et a1 Dec. 1, 1942 10 pages 334, 335 and 337 to 344 cited.

Kinematograph Weekly 270: p. 32, Aug. 31, 1939.