Development of Novel Color Papers with High Color Reproduction and High Image Fastness

Abstract

A new composite of technologies was developed and has been introduced in amateur-use color photographic papers. This consists of a key technology of a novel magenta coupler whose dye has excellent absorption characteristics and other two assisting technologies, i. e. a specific light stabilizer and anti-dirt (anti-stain) agents. The magenta coupler has a novel 1 H-pyrazolo[1, 5-b][1, 2, 4]triazole skeleton, which is quite different from an usual magenta coupler 5-pyrazolone, and which was a five ring-five ring fused heterocycle first synthesized by nitrogen-nitrogen bond formation reaction. Spiroindan compound was discovered mostly useful for a light stabilizer of p yrazolotriazole dye through the research of light fading mechanism and also by screening of various light stabilizers. This compound was found to act a quencher of singlet excited state participated by bimolecular pyrazolotriazole dyes (probably excimer) and has lead to 1.5-2.0 times faster magenta image on new color papers than that on the previous one. Anti-stain agents are an active carbonic ester (electrophile) a nd a sulfinic acid compound (nucleophile), which are designed to react effectively with p-phenylendiamine (color developer)and quinone dimine (oxidized color developer), respectively. Magenta stain, which is occasionally formed by oxidative coupling reaction of the pyrazolotriazole coupler and a very small amount of color developer remained in a paper after color development process, is completely suppressed by these two scavengers.