PUTTING GESSO OR PRIMER ON A PREPRIMED CANVAS??
I first posted on this subject in February, but since then I have been studying some more information about the subject. The info below is good of course, but there are easier things you can do as well and those are listed at the end. I want you to have the latest information while keeping life simple, right?
Why do you gesso a preprimed canvas? Because you want your painting to last. This is true especially if you are painting in oils. The acids in your paints as well as solvents will eventually eat into the canvas and rot it. It will happen over time and according to "Murphy's law" it will happen with your best paintings! Also with oils, we want the canvas as stiff as possible to avoid any cracking of the paint. So questions to consider are first how to buy canvas, then how to prepare it for painting, what do you use and how do you use it? What do you look for when purchasing a canvas? There are several things to check if you want a good one:
1. Check that the canvas is tight by flicking the canvas with your finger and listen for the sound. It should be a good deep thud. If it is dull or pushes easily the canvas is too loose.
2. Turn the canvas over and check to see if there is a gap between the canvas and the stretcher bar. It will be a small space but they should not touch. This is so that the stretcher bar doesn't show in the painting. If too loose the painting will show the impression of the bar and that's bad because it cannot be corrected easily.
3. Lay the canvas down on a flat surface or even on the floor and check that it is not warped, if it is it will rock back and forth when touched. That cannot be fixed. Put it back and pick another canvas!
4. Choose a canvas with the staples on the back not the side. Most canvases come back stapled now which is nice. They fit into a frame much easier or can be painted on the sides and left unframed.
1. The first step is to size the canvas:
Using Golden GAC 400 sizing or fabric stiffener, and a wide nylon brush (3" or larger) pour sizing on canvas and spread on canvas working it into the canvas well, including sides and back. Do one coat. Do not shake bottle to mix. Instead, roll the bottle back and forth to mix well. This prevents bubbles. Allow 30 - 60 minutes drying time between each coat of this process.
2. Next, paint on two coats of Golden GAC 100 polymer to seal the canvas well. This prevents impurities from leaching into paint from the canvas.
3. Now comes the gesso. Be sure your gesso is of a good quality and is thick, not thin, otherwise you have to add a LOT of coats of gesso! Use a 2-3" brush for this and be sure to coat the sides and back as well. Any stroke is fine, but try to get the coat of gesso on smoothly. If hairs get into the gesso, just flick them out with the brush as you go and be sure to let the gesso dry thoroughly between coats. When the gesso is thoroughly dry, take a sponge sanding block and VERY LIGHTLY go over the canvas to knock off any bumps or lumps, etc. Rub your hand over the canvas when finished to check for imperfections. You will do 2-4 coats with sanding after each, but DO NOT sand the last coat of gesso. Again allow 30-60 min of drying time between coats. If it feels cool to the touch it is not completely dry. If you prefer a toned canvas like I do, you can tint the last coat of gesso with Acrylic color instead of adding another layer of paint for toning the canvas. Use acrylics to tone the canvas even for an oil painting! Let dry for a couple days if you have several coats of gesso to make sure the canvas is completely dry.
**NEVER try to paint acrylics or gesso over oils! It does not work! You CAN however paint oils over gesso or acrylics!
There are several good YOUTUBE videos on canvas preparation but the one by Opus Art Supplies called "Surface Preparation: Sizing and Gesso" is especially informative.
UPDATE: YOU CAN ALSO USE:
* There are primers that are best for oil painting. One that has been highly recommended is Gamblin Oil Painting Ground. It is not expensive, but makes a big difference in how long your painting lasts and produces a smooth surface. (16.46 / 8 oz, Jerry's Artarama)
* As for gesso, a well known artist uses Liquitex Gesso only. He likes it because it is smooth and pours on. He pours a small amount on the canvas and then using a good quality metal putty knife he smooths it out on the canvas and wipes the excess from the blade back into the bottle of gesso. He applies 2 or 3 coats as he likes a very smooth surface, and he will sand between coats.
Below is an 8 x 10 painting I worked on in the Smokey Mountains of Tennessee, USA.