Some of you may be wondering, what is gesso coated paper? The simple answer is: watercolour paper that has been painted with gesso prior to being painted with watercolours.
Gesso is a kind of primer. Acrylic and oil painters use acrylic and true gesso, respectively, to prime canvases or wood before they paint on them. Basically, it creates a toothed surface which is not absorbent and which the paint binds well to. For the watercolourist, however, the paint is not bound, and it can be manipulated more than once, as it remains on the surface (not soaked into the paper) and soluble. It provides both challenges and new freedom of expression, especially because the paint can be wiped off almost as easily as it is applied. Once you are done, a spray finish is used to bind the paint to the surface, and it is framed like a traditional watercolour.
I learned the use of this medium in 2004 during a week-long workshop taught by Don Getz (AWS), when I was an active signature member of the Saint Louis Watercolor Society. Roughly a third to a half of my paintings are now done on gesso coated paper, as it provides an alternative for achieving certain images and keeps my creativity refreshed. I will be teaching a day-long workshop or two on this in the new year. There is more to know!!