Color (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color categories, with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum.
Cesare Catania as painter and sculptor knows very well how to use and mix the colours one each other.
In this example you can see how mixing 4 colours (black, white, yellow and red) the most famous artist in the world create the first contemporary art sculpture for clourblind people.