Frosting and Color Coating is the practice of making clear glass with a matte appearance by putting the glass in contact with the fluoride-based acid material. Glass is frosted to enhance the appearance, either over the entire surface or in designs. Frosting can be thought of as a subtractive process, one in which small quantities of the glass surface is removed, leaving behind a disrupted glass surface. These disruptions cause light that passes through or reflect off the glass to become diffused. It is this diffusion which makes the glass look frosty.