Technically, you don't. It provides you with a nice, slightly more absorbent surface to work on, especially if your working on board or raw canvas, but for a pre-primed canvas it's unnecessary. Don't forget your pre-primed canvas from the art store already has a layer of gesso on it.Mar 15, 2016
What exactly is gesso?
"Gesso", also known "glue gesso" or "Italian gesso" is a traditional mix of an animal glue binder (usually rabbit-skin glue), chalk, and white pigment, used to coat rigid surfaces such as wooden painting panels as an absorbent primer coat substrate for painting.
How do you mix gesso?
The first thing you need to do is grab a bowl, scoop out a dollop or two of the Gesso, and pour in some water. I don't really measure out specific amounts, I just add a little bit at a time until I get the consistency right. Take a couple of minutes to thoroughly mix the water and Gesso, getting rid of any chunks.Jun 29, 2007