What a read there is on http://www.handprint.com/HP/WCL/water.html. The autor is a certain Bruce MacEvoy, who, from what I learned was a top guy at Yahoo! Bruce seems to be extremely resourceful and this site is really a M U S T R E A D for any serious watercolourist who is interested to know how watercolours work. Bruce delves into the chemistry, physics and history of the medium and embellishes the site also comments on some the great watercolourists work. One of the best (if not the only) technical and scientific study of the pigments, colour theory, paper, etc related to watercolour. It's too much to take in one go, but if you bookmark it, you can refer to it when needed. There's also an interesting anecdotal history of his ventures in this medium. A most interesting read!
Andrew Borg is a Malta-based painter, working in oils and watercolour. He captures images which, to my mind, look good or have are quirky enough to have a below-the-paint meaning.