Recently I have been asked about my surface texture and what I use to prime my supports. I've done a fair bit of research into different methods of priming and tried various techniques and surfaces. Of late, I've settled on using an absorbent mid tone gesso on my boards. I prefer boards because they don't have bounce/give, they take more punishment and are smooth (no canvas texture showing through).
So what is Gesso? According to Wikipedia, Gesso is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. I've experimented with making my own gesso/absorbent ground by adding gypsum (also known as plaster of Paris), acrylic binder medium, and acrylic paint). I Add equal parts acrylic (mostly binder with a dab of green paint for colour) and plaster, this seems to be a good ratio for achieving a texture and absorbancy I'm happy with. I first heard of the equal parts plaster and binder method from the catalouge 'Art, Love & Life'
I've use a mid tone green (instead of white) to do my under painting on ever since I saw this video on Youtube about Sargent's painting methods. It seems to work well.
Paul DuSold -
The John Singer Sargent Method of Painting