Screen engraving photo etching - uses half tone method of exposing film via diffusing layer and half tone in five stages

摘要

Screen engraving is by photo etching using a half-tone positive by exposing a light-sensitive material through an engraving screen with the required number of transparent transverse lines. The light-sensitive material is exposed to the light source via the half-tone positive. The light-sensitive material is exposed to the light source through a diffusion layer between the half-tone and the film. The sensitive material used can be a carbon resist (1) which is made sensitive by submerging in a solution of potassium dichromate and drying. The engraving is carried out in five stages.