The effect of grinding on the apparent color of the yellow sugar powder

Abstract

Understanding the grinding technique as a very useful tool for super fine powder manufacturing is critically important. The colors of powders are related to the fineness of the powder. This paper contains the results of experimental studies of the effect of grinding on the color of the yellow sugar powder. The fineness of the yellow sugar samples has been monitored by a granulometric analysis. The powder sample is sifting through a stack of mesh sieves, separating it into discrete size ranges. After sieving, yellow sugar powder distinguished by various degrees of grinding is transferred directly to the computer screen by a USB microscope. Color changes have been studied by using RGB (Red, Green, Blue) and HSL (Hue, Saturation, Lightness) color models. For the yellow sugar, color changes from dark yellow to white due to diffuse reflection on the powder particles. By fitting the experimental data the dependence of the L and S values on diameter has been established. Based on recorded Raman spectra, the diffusive reflectance and the absorption coefficients have been determined.