Ascorbic acid developing compositions containing sugar and methods of use

#This invention relates in general to photography and in particular to improved black-and-white developing compositions. More particularly, it relates to improved and stabilized ascorbic acid developing compositions and to methods for their use in processing photographic silver halide materials.

#Photographic black-and-white developing compositions containing a silver halide black-and-white developing agent are well known in the photographic art for reducing silver halide grains containing a latent image to yield a developed photographic image. Many useful developing agents are known in the art, with hydroquinone and similar dihydroxybenzene compounds and ascorbic acid (and derivatives) being some of the most common. Such compositions generally contain other components such as sulfites, buffers, antifoggants, halides and hardeners.

#Dihydroxybenzenes (such as hydroquinone) are the most common black-and-white developing agents and are quite active to provide development in various black-and-white photographic elements with or without booster and nucleating compounds. However, they are disadvantageous from several technical and environmental considerations. For example, hydroquinone compositions are not completely stable in air, being prone to aerial oxidation. The by-products from instability are often insoluble, black and tarry materials that contaminate the processing solutions and equipment.

#FIG. 1 is a graphical representation of stabilization data generated for Example 1 below.

#The present invention is useful for black-and-white development in any photographic silver halide material requiring at least one black-and-white development step. Such types of silver halide materials include, but are not limited to, particularly, radiographic films, aerial films, black-and-white motion picture films, duplicating and copy films, graphic arts films, positive- and negative-working microfilms and amateur and professional continuous tone black-and-white films. The general composition of such materials is well known in the art but specific features that render them particularly adaptable to the present invention are described below in more detail.

#In addition, the black-and-white developing composition of this invention can be used in the “first” (black-and-white) development of color reversal photographic silver halide materials (details described below).

#The black-and-white developing compositions of this invention contain one or more ascorbic acid developing agents. An “ascorbic acid” developing agent means ascorbic acid and derivatives thereof. Ascorbic acid developing agents are described in a considerable number of publications in photographic processes, including U.S. Pat. No. 5,236,816 (noted above) and references cited therein. Useful ascorbic acid developing agents include ascorbic acid and the analogues, isomers and derivatives thereof. Such compounds include, but are not limited to, D- or L-ascorbic acid, sugar-type derivatives thereof (such as sorboascorbic acid, γ-lactoascorbic acid, 6-desoxy-L-ascorbic acid, L-rhamnoascorbic acid, imino-6-desoxy-L-ascorbic acid, glucoascorbic acid, fucoascorbic acid, glucoheptoascorbic acid, maltoascorbic acid, L-arabosascorbic acid), sodium ascorbate, potassium ascorbate, isoascorbic acid (or L-erythroascorbic acid), and salts thereof (such as alkali metal, ammonium or others known in the art), endiol type ascorbic acid, an enaminol type ascorbic acid, a thioenol type ascorbic acid, and an enamin-thiol type ascorbic acid, as described for example in U.S. Pat. No. 5,498,511 (Yamashita et al), EP-A-0 585,792 (published Mar. 9, 1994), EP-A-0 573 700 (published Dec. 15, 1993), EP-A-0 588 408 (published Mar. 23, 1994), WO 95/00881 (published Jan. 5, 1995), U.S. Pat. Nos. 5,089,819 and 5,278,035 (both of Knapp), U.S. Pat. No. 5,384,232 (Bishop et al), U.S. Pat. No. 5,376,510 (Parker et al), Japanese Kokai 7-56286 (published Mar. 3, 1995), U.S. Pat. No. 2,688,549 (James et al), U.S. Pat. No. 5,236,816 (noted above) and Research Disclosure, publication 37152, March 1995. D-, L-, or D,L-ascorbic acid (and alkali metal salts thereof) or isoascorbic acid (or alkali metal salts thereof) are preferred. Sodium ascorbate and sodium isoascorbate are most preferred. Mixtures of these developing agents can be used if desired.