US Patent 7586656 Process for producing optimised printing forms

The invention is a process for producing an optimised printing form comprising printing onto a substrate with a printing form with predetermined raster percentages on the printing press to obtain a test print in form of a stepped wedge with raster patches, measuring the reflectance spectrum of each raster patch, determining associated colorimetric values L*,a*,b* from the reflectance spectrum, transforming the colorimetric values L*,a*,b* for each raster patch in linear correlation with the color perception of the human eye, using the formula