Color is an event that occurs among three participants, light source, object and observer.

It should come as no surprise that one and the same object will look different under differing light sources.

Your clothes do not have the same color under a fluorescent tube, a regular light bulb or in sunlight.

However, most of the differences are 'corrected' in our brain by a psychological process called 'color constancy'.

A color is always composed of light of different wavelengths.

Sunlight, for instance, can be deconstructed to the colors of the rainbow but a surface can also be deconstructed in a spectral analysis.

This is the spectral analysis of a certain shade of red:

This is the spectral analysis of almost exactly the same color red:

There's something peculiar about these two colors: they are metamere.

Which means that perceived in a certain light, in this example sunlight, they will appear exactly the same to our eyes. But under another source of light, say an electric bulb, they will appear different.

Metamerism is a quite common phenomenon that can cause problems in color schemes.

If, for instance, the same color is ordered from different manufacturers, there's a distinct possibility that they will be metamer, which means they will not be the same in all circumstances.

This is because different manufacturers use different pigments.

Metamerism is something to keep in mind when trying to match two colors. You should therefore make sure to match the colors under the proper light source.