一、序言近年来,由于世界白银产量远远低于需求量,造成银价不断上涨,因而在感光材料领域中正积极开展节银和代银技术研究。人们发现,显影后的黑白照相材料,在定影和水洗不充分的情况下,黑白显影剂如对苯二酚、邻苯二酚和连苯三酚等氧化产物会产生褐色或黑色的染料,沉积在显影银表面,增加银影像密度,因而通过一种或几种染料来强化或产生黑色影像,已为人们所关 I. Preface In recent years, due to the world’s silver production is far below the demand, resulting in rising silver prices, so in the field of photosensitive materials is actively carry out section of silver and silver technology research. It has been found that the developed black-and-white photographic material produces a brown or black dye upon oxidation of a black-and-white developer such as hydroquinone, catechol, and pyrogallol, in the case of insufficient fixing and washing, On the developing silver surface, increasing the density of the silver image and thus strengthening or creating a black image with one or several dyes has been of concern