The light doesn’t pick up the color, but it is the object that picks up the light coming from the back. The left over goes off the object and come to your eyes, hence you see the color of light that it does not absorb. So if the object is red, it means that it only led red light pass through. When there is no light coming from the back, it will be black. (You might notice that the colors of the glass windows of a church are vivid from the inside, but almost invisible from the outside)
The color might also comes from scattering, e.g. the sky is blue due to Rayleigh scattering
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