Abstract
The color of inorganic pigment consists of the reflecting and permeating lights. The reflectance of inorganic pigment is dependent upon both primary and agglomerated particle size and shape. As for the iron oxide pigment with red tone color, the tone color changed systematically from yellowish red to red, dark red, dark purple and black, with increasing the particle size and changing the particle shape. The permeating color of the pigment is determined by atomic position and electron state. Molecular orbital calculation could simulate the color of permeating light.
