金在直接正性乳剂中的作用

直接正性乳剂预灰化时，金有重要作用。本文使用在灰化结束后加入卤化银溶剂的方法研究金在灰化过程中的作用，并交替应用金浴（Ａｕ＾＋）增强灰雾中心，再用氰化钠浴（ＣＮ＾－）选择性地除去灰雾中心的金，研究金与灰雾中心的作用。实验表明，在灰化过程中加入金可以影响灰雾中心大小分布；当乳剂层内还原剂量大时，沉积反应是主要反应；而当乳剂层内还原剂量少时，置换反应是主要反应。直接正性乳剂还原灰化时，Ａｕ＾＋被还原而

The Effects of Gold in the Pre-fogging Process of Direct Positive Emulsions

Gold plays a very important rule in the pre-fogging process of the direct positive emulsion. In this paper,the effects of gold on the formation of fog centers were studied by adding silver halide solvents after the emulsions were fogged by thiourea dioxide and thiourea dioxide plus gold, respectively. The interaction between the gold and the fog centers was studied by alternatively immersing in the gold bath and sodium cynide bath. The results indicated that the presence of gold during fogging can make the fog center size distribution narrow. It was also shown that the deposition of gold is the main reaction when there are plenty of reduction agent in the emulsion layer and the replacement of silve atonies by gold may become important when there is short of reduction agent. When the direct positive emulsion is pre-fogged, the reduction of gold ions and the deposiotion of gold onto the fog centers is the main reaction, because there is plenty of reduction agent.