At one level or another, a painting speaks to our senses- whether it be spiritual, emotional, psychological or physical. As human beings, we have related to images before we had words. Many books have been written on color, and experiments have taken place to discover how different colors affect us. Scientifically, each color has its own vibratory rate, just like everything in nature, which we resonate to. We use color intuitively in our daily lives.
Colors can energize, soothe, drain, nurture, etc.
This, along with the other visual elements I listed earlier creates an extensive repertoire of tools for the visual artist. I feel that a lot of people go to galleries and museums not just to look at paintings, but to experience them. Sometimes a painting would touch them so deeply that they decide to take it home with them. Some continually visit a certain piece, like an old friend. On a spiritual level, I feel that everything a person makes carries that person's energy and intent, their medicine.