TEST METHOD FOR EVALUATING FAULTS ON PRINTED SHEETS AND WEBS

摘要

Method of evaluating faults on printed sheets by means of a reflectance meter and test fields which includes: detecting by a measuring technique reflectance values of four test fields one of which is a full tone field and the other three are line screen test fields having screen lines disposed at varying angles yet exhibiting equal screen width and equal screen tone values in the film, mathematically determining the screen tone value in a print, deducting any effect of slip and mackling from the measured four reflectance values or from the screen tone values in the three line screen test fields ascertainable therefrom; and selectively indicating these values.