HI, regarding Richard's Grand Canyon painting, it's a great example of not painting only what you see. The goal is a great painting and I too get trapped into the paint what you see, or see in the photo often. If it needs red to offset or highlight some other colors, go for it. See what color you can use all over the painting once you've mixed something you love. The more I get away from the naturalistic colors, the better the work seems to be for me. Purple or blue shadows, yellow or orange brights, put in whatever is needed to make the scene work.