Then using a sheet of white Pastelmat paper about 9" square I did a charcoal underdrawing, changing it from a rectangular format (see photo and sketch at bottom) to a square, and painted using PanPastels. Here's the result, which is still in progress:
In order to paint rocks underwater it's necessary to consider the rocks first. I suggest drawing them well, showing the underwater rocks with their shadows, if they're visible, and then consider the water's action, reflections, and ripples.
A drawing will help you see more accurately. Do a good sketch showing the placement of the rocks, either in charcoal or pastel. It’s not necessary to draw every single stone, but locate the major players, and then loosely indicate the size and general placement of scattered stones in non-essential regions.
Ask yourself what makes the rocks look wet. In the sketch above you can see that the dry rocks are generally lighter in value, while submerged ones are slightly darker. The water line indicates the shape of the rock, as well. You can clearly see the shapes and shadows cast by those beneath the water, although the contrasts are not as dramatic.
|WetCanvas RIL pic by Godzoned|
Reflections, along with light and shadow, affect how you see the water and stones under the surface.
I suggest you paint from bottom to top, beginning with the river bottom, any stones seen beneath the water, then its surface and any rocks above water.
I saw some wonderful pencil drawings begun in class as my students started to sort out rocks, both wet and dry, water and its reflections, bubbles and foam, and the shoreline rocks and trees.
Keep going, gang!