The sun produces electromagnetic radiation, some of which we know as radio waves, UV rays and visible light. Everything we see around us is a reflection of this visible radiation. Artificial light is meant to reproduce the properties of sunlight, but nature is difficult to imitate and most products are fall short.
A ripe tomato is red because it absorbs every wavelength other than in the red spectrum. However, if your light source has weak or non-existent light in the red spectrum, your tomato will appear orange/brown.
Capturing what we see and experience has become an important part of our lives. Dull or missing colours can make your images appear lifeless and time consuming or even impossible to fix through editing.