The color appearance of masterbatch varies from different producers. Some masterbtach is much brighter and some is darker. One of the reason is that the masterbatch with better color is added with optical brightener. Most master batch is added with titanium dioxide for the whiteness. But the reflectivity of titanium dioxide to incident light is not 100, and the light absorption rate for bule and purple color is high. This will make the whiteness not that good. But if optical brightener is added, it can absorb ultraviolet light with wavelength of 300-400nm, and then emit blue-violet fluorescence. This will significantly improve the color and whiteness of the masterbatch product.