We propose a methodology to identify the address labels on flat mail pieces, for the cases where the surface characteristics of the address label are different from the remaining surface. Two methods are used: movement of highlights with differing illumination, and identification of highlights using color information. Reasoning about changes in hue, saturation and intensity, using a new representation of color, allows us to discriminate between matte and glossy surfaces. On grayscale images, we separate diffuse reflectance areas from glossy reflectance areas, using highlights which change with illumination angle. If that does not disambiguate the label, we use color, reasoning that highlights decrease the saturation value and increase the intensity.