Printing plates etched to varying cavity widths and depths - by image generation via negative copy superimposed on grid

摘要

Printing plate with an etched surface for producing a hatched print image is made so that the surface cavities for accepting the ink vary both in depth and area according to the local intensity variations required in the image. Used for producing images to be read by e.g. laser scanning sensors. Quicker to produce than plates where contrasts are obtd. by successive etch treatments to vary the cavity depth. Capable of a wider range of contrast for a given definition than plates in which intensity variations depend only on cavity spot area.