Analysis of Halftone Dot Structure I: Observation of Dot Spread

Abstract

In order to understand the imaging characteristics of xerography, it is essential to compare dot gains of various hardcopy output systems such as Chromalin, offset printing, etc. For such a purpose, the most desirable definition of dot gain is “Dot area expansion caused by the dot thickness reduction compared with the one at the solid area”. According to this definition, the amount of dot gain can be semi-quantitatively estimated both from the cross-sectional dot structures and by colorimetric measurements of halftone wedges because any thickness change in the colorant layer sifts the color of the image. The cross-sectional details of the dots were characterized by the observations with a TEM and an optical microscope, confirming the validity of the present colorimetric analysis.