Metamerism exists when two materials match under some lighting conditions but not under other lighting conditions. It is the occurrence of colors which have different properties appearing to match under a particular light source, yet under other light sources they appear to mismatch. This can be a serious problem for manufacturers. If you combine different materials or materials from different sources into one product, metamerism may occur. For example, you want all the parts of a car that are the same color to match whether it is a sunny or cloudy day. Or if you bought a suit you’d want the jacket and pants to match the same way in daylight as they do under the fluorescent lights of the department store.