Effects of preparation methods on color properties of ZnO-based nano-crystalline green pigments

Zn Co O green pigments, with crystallite sizes from 29 to 181 nm, were synthesized via solid state reaction and solution combustion using different fuels. The effects of experimental conditions on the color properties of the pigments were investigated by means of the spectral diffuse reflectance and the color coordinates determination. The results showed that the maximum perceptible color depth was obtained for the combustion method with citric acid. The calculated color properties as well as the hue angle values around 1578 confirmed a similar green shade with lightness ranging from 34 to 62. A good accordance was demonstrated between the results of the color properties in terms of the adsorption parameter of and the crystallite size variations. and are the coefficients of absorption and scattering of monochromatic light of an opaque substrate. The optimum color characteristics were obtained for the combustion synthesized sample by using citric acid as fuel.