Above is another Waugh of course. I keep posting his paintings because they are such good examples of seascape. They get me all excited about painting seascape. I hope they do the same for you. Some of you who are out in the Midwest may be zoning out on all this seascape stuff, and I am going to give it a rest soon, and write about something else. But I will return to the subject and do some demos in a couple of weeks. I have to make time to prepare those. I am madly burning the candle at both ends.
Rocks are the other element in seascape. The composition of a seascape is often a designed interplay between the dark rocks and the light sea. The water and sky often function as a single unit . They can be part of the same value area and share a lot of values and colors. Remember back when I was discussing snow painting that I talked about the paper doll idea? It applies here too. If the sea and the sky are in a high value, all of the rocks are laid on top of them, like paper dolls cut from black paper land placed on a light ground. The rocks are essentially silhouetted in front of the water and sky. This isn't always the case but it does happen a lot and seascape painters use this as a design motif. That is another reason why back lighting seascapes is so common.
Here is a photo showing that. All of the rocks are down in a low value, although they do have some lights in them they are all well below the value of the sea. It is easy to lay in the rocks as and interesting series of interlocking darks and then decorate them with some color and value variation to get variety in them. The trick is not to chop them up to much, but keep them unified.
Looking at Waughs work, I believe he often toned his canvas dark at the outset and then painted the water light down onto that, leaving his dark for the rocks. I have experimented some with that and it seems like a good system.