(Posted by Bill)
Okay, bad joke. But painting underwater rocks is fun, especially when they're under some relatively clean, shallow water. You can achieve a believable effect with just three values of the same hue. In this case, a cool green. You can also use a little of a warmer color picked up from the dominant local rock color.
Addendum, by Maggie: I've learned a lot from watching Bill paint underwater rocks over the last few years. I think the most important thing you have to achieve is a feeling of layers—the underneath layer of rocks and river-bottom, the layer of water, and finally the layer of the surface. In this painting, the water is shallow, as Bill notes. So there's really just the bottom layer of rocks and sand, and the top layer of the surface of the water. He's created that top layer with just a few marks to indicate the movement of the water.
This river in northern California is very beautiful, especially in the early spring when it runs deep and fast. It's also the greenest river I've ever seen. Bill caught that color perfectly in this painting.
Above, Smith River Shallows II, 6x9 pastel, ©Bill Canright, $95