When building a painting think in terms of colorful grays. Use the color wheel to help with creating these grays by combining complimentary colors. When you have these grays be sure that your values are correct and that they are going from lighter in the background to darker and richer as you come forward. This will give you a solid foundation to build on and embellish with purer color and higher intensity light.
Nature is greyer than we think. Using complimentary colors to paint a blue sky, for example, I’ll use Lead white, Ultramarine blue and Cobalt Turquoise then greyed with a dash of either transparent red oxide or Burnt Sienna which is considered an orange.
What are your favorite combinations of colorful greys, Al?
I think the greens. I paint a lot of trees and grasses so creating differences within them especially in one painting, makes a tremendous difference. Combinations of yellows and blues and blacks and yellows give a very large palette of greens then adding different reds to them gives endless possibilities.