Two days of beautiful weather in a serene location made this plein air paintout a most pleasant experience. I was situated in a shady area with only fleeting moments of sunlight peeking through the leaves. Consequently, there were some strong darks under the rocks, etc. I was having difficulty mixing colors dark enough. Then I remembered, in a workshop with Ron Donoughe, his suggestion of a mixture of Thalo Green and Alizarin Crimson to make black. I used this to darken other colors. It worked. Thank you, Ron.