Applying gesso to a canvas is really easy. Get a large, flat brush, load it up with gesso and gently brush it on to the canvas. The aim is to cover the entire canvas in a smooth and even layer of gesso, so be sure to smooth out any lumps or bumps. It’s up to you how many layers you use to prime your canvas with. Try doing a few different paintings, each with a different number of layers, and see how you find each one. You’ll notice that the more layers you have, the less the paint soaks into the canvas.
You don’t have to prime your canvas with gesso if you’re doing an acrylic painting, though it certainly does help to do it. If you don’t prime your canvas, the paint will soak into the canvas material a lot more easily. You’ll find that a lot of canvases come pre-primed – these canvases have already had a layer of gesso applied to them, so you don’t have to worry about applying gesso to them. However, if you’re used to working with a few layers of gesso, you might want to add an extra layer or two. An unprimed canvas will give you very deep staining effects.
If you don’t want to have a white layer for your primer, you don’t have to. While normal acrylic gesso comes in titanium white, you’ll find acrylic gessos in many different colours that are available to purchase. Alternatively, you can create a coloured gesso yourself; all you have to do is get a different colour of acrylic paint and mix it in with the white gesso before applying it to the canvas. By doing this, you can prime your canvas with any colour you want. If you want a more textured surface as your primer, mix a texturing gel in with the gesso before applying it to the canvas.
As with all art supplies, you’ll find a wide variety of gesso variations. Some gesso products will give a smoother effect when applied on the canvas, while others will give the canvas more of a textured look. Consistency can also differ among brands: some gessos can be quite thick and more like a solid, whereas others can be really thin and more like a liquid. You should also bear in mind the differences between student grade gesso and artist grade gesso: student grade gesso usually only comes in white and is a lot cheaper, though it has less pigment and less consistency. Artist grade gesso, on the other hand, is a lot more expensive, though it does come in different colours and is a lot thicker than student grade gesso.