ИСТИНА

Physical and chemical base of photographic process on the main stages (chemical sensitization [CS], exposure and development) is connected with reactions of reduction of emulsion microcrystals (MC). These reactions proceed up to different levels and are often combined together. The evolution of silver during chemical sensitization determines the formation of sensitivity centers and fog centers and therefore this process is directly connected with photographic speed formation. The analysis of original results and literature data on the problem of association and redistribution of silver atoms during formation and growth of silver specks is given. The correlation of structure and centers compositions with sensitometric characteristics is discussed. It is noted that the data connected with mechanisms of individual stages are often contradictory. The alternative approaches to the nature and sizes of latent image centers which are able to initiate the total reduction of emulsion MC during development process are also discussed.