Using an oil based gesso (aka oil ground)
It’s different than acrylic gesso!
Pros of using oil gesso over acrylic? An oil “ground” (gesso) is less absorbent than acrylic gesso and applied properly can produce a smoother surface to paint on than the chalky acrylic.
If you’re familiar with oil paint you may think, but if the gesso is oil based what keeps the canvas from eroding then, because isn’t that the point of using acrylic gesso? To create a barrier between the corrosive qualities of oil paint and the canvas weave? You would be right! There is an extra step when using oil based gesso, called “sizing.” The “sizing” must be applied to the raw canvas BEFORE the oil gesso. This sizing basically functions similarly to acrylic gesso, it is the barrier layer between the raw canvas and the corrosive oil. Now, how do you buy “size” at the store? Well, back in the day they used rabbit skin glue- exactly what it sounds like- as the size. Which is difficult to use in that you must first carefully heat the glue and apply the sticky, cooking-pot-ruining, substance to the canvas. Not to mention it smells. But we live in modern times! So Gamblin has a product called PVA size, a synthetic substitute for the rabbit skin glue. This PVA must be applied to your raw canvas, let it dry for a day, and then apply the oil gesso with a spatula to avoid brush strokes and create the smoothest surface. After a few layers of your oil gesso, let it dry for a WEEK before painting on it!!!! Treat it the same as you would your oil paints, it needs time to dry. All these extra steps will leave you with a uniquely smooth layer to paint on. It’s fun to experiment with, especially if you paint in very thin layers and tiny details like I do.
Here’s your cons for using oil gesso: Longer dry time. You can not quickly prep the canvas, gesso and paint on it the next day like you can with acrylic. It also has the extra step and cost of using a sizing product (the PVA).
Image from Gamblin Paints
P.S. If you’re new to oil painting: you can safely use oil paints on acrylic gessoed canvas, this is also what the store bought canvases have on them. If you want to upgrade your store prepared canvas though, add another layer of gesso yourself to create a better surface.
Buy PVA size and oil ground gesso here:
Resources for more information on the Gamblin Website: https://gamblincolors.com/sizes-and-grounds/
