Half tone tactile pictures - have deep etched metal master with rubber moulded prints suitable for feeling by blind people

摘要

A half tone tactile picture is prepared by deep etching a raster pattern on a metal master, with the raster modulated by the picture content. The master is etched deeper than a print master, and with a coarser raster. A silicone rubber moulding, with the image printed on top forms the tactile emulsion. The process changes conventional pictures into tactile images which can be scanned by the sensitive, trained fingers of blind persons. The etched pattern can be prepared by conventional photolithographic processes or by a programmed laser etcher.