Choosing the appropriate color-measuring instrument does not have to be difficult. There are basically four geometries for color-measuring instruments: sphere-based specular-included, sphere-based specular-excluded, 0/45-degree and 45/0-degree. Although determining the most appropriate instrument really depends on the application, a few general rules apply. To negate the effects of surface characteristics, such as gloss, texture and pattern, use a sphere-based instrument in the specular-included mode. To measure appearance, use a 0/45- or 45/0-degree instrument.