用铜物理显影的多级放大成像过程 Ⅰ.影像强化和节银效应

感光乳剂中卤化银颗粒接收足够的曝光量后可形成潜影,经过显影便成为可见影像。这个过程可以看作是第一级放大。它的放大因子为10~9。但是影像的密度取决于单位面积上显出的银量和银影像的遮盖本领。如果单位面积上显出的银颗粒太少,影像就不能被眼睛或仪器(如密度计)检测出来。单位面积上银颗粒太少可由两个原因造成的:或是因为曝光量太低以致具有可显潜影的颗粒太少;或是因为乳剂层中卤化银颗粒本来就太少。

AN IMAGING PROCESS WITH MULTI-STAGE AMPLIFICATION BY COPPER PHYSICAL DEVELOPMENT

The imaging process with multi-stage amplification by copper physical development was studied with different emulsion coatings: the positive cine film, the negative emulsion coating, the direct positive emulsion coating and radiographic film. The results. showed that the sensitivity of the emulsion layer can be increased significantly by the copper physical development and the amount of coated silver can be greatly reduced. It is extremely interesting, as shown in this work, that a Lith Effect can easily be obtained by the copper physical development. The imaging process with multi-stage amplification can find practical applications in the following cases: i. the enhancement of faint images otherwise would not be detected; ii. the development of photographic materials with extremely low silver content; iii. the reduction of X-ray dosage in medical rediography.