Pigments in Paper Industry

Pigments are used in the coloration of paper. If the brightness of the paper has to be decreased then the percentage of red and yellow part of the visible spectrum has to be decreased. In such cases, pigments which absorb these parts can be added. Their addition will reduce the paper’s brightness as desired quite contrary to the result attained with an optical-brightening agent. On the other hand if the paper whiteness has to be increased then pigments are used along with an optical brightening agent. At such times, violet and blue dyes are the most commonly used pigments. https://vipulorganics.com/blog/2016/09/19/pigments-in-paper-industry/