In painting, drawing and painting a face is initially loosely - idea in a nutshell - brushes with mid-size or large (much matter to the background color, etc.)..
Towards the end of the work, its expressive meaning, the heart of all the work it blossoms in the details (short subject).
near the end of the work, therefore, little color (with finishing touches indichiamoli x) is a great expressive meaning (y). If I had to draw a graph showing the relationship between time in the amount of color and expression in a portrait, I would choose a exponential function y = x 2 .
Postscript:
Image by ffffound.com
