Continuing on Rocks & Foam

I'm working on this piece a little at a time and really enjoying rendering the stones. I'm making them a little more colorful than they are in my photo, I do have some rocks in my studio to look at also. The colors I'm using consist of many grays and browns with touches of other colors; blues, purples, red/orange, yellows. The more I look, the more color I see so I have to back off a little from making them all to colorful and not realistic. My goal is soft and subtle rocks, foam and sand with subtle colors added. While I enjoy working on the sanded grounds in which the pencil can be applied quicker, I have to say my favorite surface is rag illustration board because its durable and takes the pencil softly. Once in a while I don't mind taking forever on a drawing because I enjoy the process and the outcome.