One of my favorite art instruction books is “How to Make a Watercolor Paint Itself” by Nita Engle. Nita includes a variety of experimental techniques for creating dramatic waves, clouds, and atmospheric backgrounds. One that I use quite often is her 6-way wash. It works well for establishing skin tones, and can also force me away from trying to match the colors in a reference photo.
To create the wash, the entire area is wet with clean water. A central area of light color is painted, then ringed with a second color. A third color is painted around the outside. The entire surface gets a spritz of water, and then you pick up the paper or board and tilt it back and forth, encouraging the colors to merge and mingle.
Taking this approach further and thinking about backgrounds for landscapes, I experimented with a few different washes. The first combo was selected to indicate sunlight through the forest. Rather than using all greens, I tried adding a pink tone to the mix for warmth. This is Phthalo Yellow Green, Rhodonite Genuine (the pink) and Perylene Green.
This technique would also work for the inside of a large, scalloped shell, using Mars Yellow, Rhodonite Genuine and Manganese Blue Hue. The lifted area shows how the paint could be removed to create the raised folds of the shell.
Find Nita’s book on Amazon: How to Make a Watercolor Paint Itself