Transparency, a method for forming it and a photographic mask whose optical densities are correlated with the contour of a surface

摘要

Disclosed is a transparency, a method for forming it and a photographic mask having variations in optical density corresponding to deviations of a surface contour from a plane of an original surface. The transparency is a composite two layer, transparent, preferably resinous structure with a contoured interface between the layers. The transparency may be made by forming a first conformed transparent layer on the contoured surface of a substrate. A second conformed transparent layer is then formed on the contoured surface of the first transparent layer. One of said first or second transparent layers is uniformly colored, the other of said layers may be uncolored, or have a less intense, uniform, similar, or different color. Each of the layers has a refractive index substantially equal to that of the other layer at all points. Light may be passed through the transparency in substantially unrefracted rays, and in amounts related to the thickness of the most intensely colored layer. A photographic mask, or plate having variations in optical density corresponding to those of the transparency may be formed by passing light through the transparency onto a film, or plate positioned thereunder.