Contrary to what we may believe, we do not sense color. While that may sound counter-intuitive it is indeed true. Color is the visual experience that arises from our biology interacting with the spectral composition of the light (electromagnetic radiation) that is emitted, transmitted, or reflected by the environment.
For example, what you might perceive as a “blue” sphere is not physically composed of what we might understand as “blue”. Rather, it has a surface that absorbs all wavelengths of visible light except some that are relatively short. Now we have a certain type of receptor cell that is “tuned” for these short wavelengths. When that cell encounters a short wavelength from the environment, it generates an electrochemical signal that propagates along our visual pathway (along with many other signals) to generate our experience of “blue.” So no, the sphere itself not physically blue, the wavelengths encountered from the sphere are not blue, nor does the cell referenced above “sense” blue. We assign “blue” to a particular sensation that is a reflexive response to a certain wavelength.
This is indeed a simplification of the process but I hope it may makes the general concept a little bit easier to understand.
Happy Painting!