Call of saint Matthew, Caravaggio, color analysis

I remember from the old days t the university, when I saw the students in the third, fourth and fifth year of the speciality of painting, doing their preparatory drawings in a kraft paper with bistro or charcoal, and besides, in a small piece of paper, canvas or wood, a simplified version of the painting, reduced to rectangles. This was the palette. From there they will take guide when perparing the final piece. This is an attempt to doing the same but digitally. And here I processed two versions, one with more rectangles, and the other with les. Rectangles or squares, is the same, the point is to try to define the color areas independently of the shape and the softness  (or hardness) of the lightning. The light should be felt by the relationship among colors. I remember learning a lot from people like Jorge Caparo and Luis Najera. But they are just the first that come today to my mind.  I learn a lot from many of the artist growing there. Everyone has some aspect from which I could learn.