Opacifiers are sometimes used in liquid detergents to produce an esthetic or special effect.  Such opacifying compounds are of large molecular structure and are water insoluble, but lend themselves to forming a stable colloidal dispersion. Titanium dioxide, a pigment, is widely used in milled soaps for opacification, or to reduce translucence, and may be used alone to make the bar white or, when dyes are added to produce a desired color.