Money -- we chase it, stack it, blow it, can't get enough of it. It makes the world go 'round and solves at least 83 of the 99 problems we have. But don't take my word for it, instead listen to these folks:
The canvas is colored with an assortment of spraypaints with a coat of black over the top. Then, through a subtractive engraving process, The black paint is removed exposing the image and colors below. The last step involves 2 clear coats to help preserve the piece.