对于曝光量低到最佳曝光量的1.5%的摄影负片来说,如密度接近于基础灰雾水平,这样靠显影液冲洗出来的像一般用密度计是测不出来的,眼睛也看不到。为了增强这种负片的极其微弱的像和反差,已经有人利用染金——中子激活处理的方法对增强影像进行研究。本文将简单介绍此项新技术。摄影侦察或情报底片胶卷的这种反差增强,可以恢复在有害光照条件下或昏暗阴影条 For photographic negatives with a low exposure to 1.5% of the optimum amount of exposure, such as density close to the base fog level, so the image of the developer rinsed out by the developer is undetectable and not visible to the eye . In order to enhance the extremely weak images and contrasts of this negative, enhanced images have been studied using dye-neutron activation processes. This article will briefly introduce this new technology. This contrast in photogrammetry or intelligence film multiplication can be enhanced by recovering under adverse lighting conditions or dark shading