All components of white light that a sample does not absorb are transmitted, and a color wheel can be used to predict the appearance of the sample. In general, if one color of light is absorbed, the sample will appear to be the color on the wheel opposite to the one absorbed.
For example, if a sample only absorbs light from 650 nm to 700 nm (red light), all other wavelengths will be transmitted. The sample will appear green, since green is the complementary color to red and is across from red on the color wheel. (Note: A sample may absorb more than one color, and predicting its appearance becomes more difficult.)