Optimization of the Method for Color Measurement of Printing on Holographic Paper

摘要

Color is one of the most important quality control parameters for printing, but there is no applicable color measurement method for printing on holographic paper. The aim of this study was to analyze the reason why current instruments are unable to provide accurate color measurement for holographic paper printing and find a way to solve the problem. Diffuse geometry instrument was proved to be more suitable than directional geometty instrument for holographic paper printing. Variations in the measured color coordinates due to holograph patterns were observed by measuring four types of holographic papers before and after printing. The distribution uniformity and the area of holographic patterns were considered as the main factors that influence measurement repeatability and consistency. By using d:8° geometry instrument in specular component included (SCI) mode and large circular measured area, measurements at two angles of the same point and averaging, or measurements at three different positions and averaging were proved to improve the measurement repeatability on a single point and measurement consistency on a single sheet of holographic paper.