Raster matrix for reproduction techniques - consists of a photographically developed thin film fitted to a glass plate

摘要

The matrix pattern is developed after a half tone vignetted exposure of the photographic emulsion on a transparent film. It is used as a distance raster for autotype image analysis by applying it to a transparent plate. A second plate is used as a protective cover. The method is claimed to be cost and labour saving. The raster reduces clouding effects and Newton rings and has good light transmission characteristics. In a typical arrangement the crystal glass plates are of equal thickness, with the grid matrix forming a sandwich of which the completely developed emulsion zones represent the maximum density and the partially developed zones the minimum density.