Light-sensitive silver halide photographic materials (hereinafter "light-sensitive material(s)") must have stability with time as one of important properties. In particular, the stability required after they has been exposed and until they are photographically processed, i.e., latent image stability, is an important factor.
Latent images formed as a result of exposure of silver halides are unstable, and may fade or intensify with time because of heat or the like, resulting in a decrease or increase in sensitivity in regard to photographic performance.
This latent image stability is greatly affected by the manner by which silver halides are produced, structured, surface-treated, chemically sensitized or spectrally sensitized, the properties of binders such as gelatin, the types of hardening agents, the pH of coating solutions, the concentration of silver ions and so forth.
In order to improve latent image stability, various methods have been proposed. For example, Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 291250/1989 discloses use of benzothiazolium; Japanese Patent O.P.I. Publication No. 17431/1983, use of pyrogallol derivatives; and Japanese Patent O.P.I. Publication No. 152235/1983, use of tetrazaindenes. Japanese Patent O.P.I. Publication No. 257947 also discloses controlling tabular grains and their surface pH.
Employment of these techniques, however, can not achieve a satisfactory improvement in latent image stability or may be accompanied by a lowering of sensitivity or an increase in fog, and hence it has been sought to make an advance of more improved techniques.