網印刷物の光沢の検討 ( 1 ) : 網画像の微視的解析

Abstract

A reflectance of half-tone printed matter decreased with increasing wave number measured. The measurement by an image processing apparatus indicates that the reflectance decreased continuously around the dot edge. The width of the reflectance change was determind to be 32μm. By the effect of the dot edge, the dot area was changed in the monitoring threshold value, the wavelength, screen ruling, dot percentage, etc.. On the basies of thies results, an equation for the evaluation reflection density was proposed on the hypothesis of a middle tone area around the dot; R=(1-a)(10)^<-dp>+a(10)^<-ds>-b((10)^<-dp/2>-(10)^<-ds/2>)^2 where b is the middle tone area. The width of middle tone area was also determind. The error limit of the equation was within 0.4%.