What Is Gesso and Why It Matters

Over my years of teaching the topics of gesso, size, what surface to paint on and what surface not to paint on have come up a lot. I want to address these FAQs in this blog post.

If you're just beginning to oil paint, you can just buy ready-made canvases that are already prepared using the methods below and ready to paint on!

Before the first stroke of paint ever touches canvas, there’s one crucial step that determines how your artwork will age: priming.

That’s where gesso comes in - an essential material that artists have used for centuries to prepare their surfaces.

What Exactly Is Gesso?

In short, gesso is a primer. It strengthens the surface of raw canvas - cotton or linen - preventing oil paint from soaking into the fabric. Without it, the oil can seep into the fibres, eventually rotting the material over time. If you've ever tried painting on raw canvas with oil paint, you'll know that the oil bleeds through almost immediately.

Traditionally, gesso was made from chalk, glue, and often white pigment. Modern acrylic gesso is easier to use and dries faster - perfect for preparing stretched canvas or boards at home. Because modern gesso is acrylic based, it also means you don't need to apply a 'size' before the gesso. Traditionally a 'size' was made from rabbit skin glue. After that a primer was applied - either white or coloured (the gesso layer).

Why It Matters

A properly primed surface:

• Protects your canvas from oil damage

• Provides a slightly absorbent “tooth” for paint to grip

• Gives you control over the surface texture (smooth or rough, depending on your preference) - you can sand layers of gesso if you want the surface smoother.

If you’ve ever wondered why your paint feels slick, patchy, or inconsistent, the surface preparation might be the culprit.

Takeaway

Traditionally the layers were:

1. Wood panel or canvas - historically it would've been linen

2. Size - A coat of rabbit skin glue

3. Primer - A coat or multiple coats of gesso.

Modern equivalent

1. Wood panel or canvas - nowadays it's common to paint on cotton duck as well as linen

2. Size and primer - Gesso. This is because, as mentioned, modern gesso is acrylic based so it replaces the rabbit skin glue 'size' layer and so acts as both a size and a primer. If you have raw canvas you want to prepare for oil or acrylic painting, you can just apply modern gesso and you're set to go. You just choose how many layers of the gesso to apply and how much sanding you want to do for the surface you require.

Learn the Whole Process

In my upcoming oil painting course, I’ll show you how to:

• Prime, tone, and prepare your own painting surfaces

• Avoid common beginner mistakes when starting a painting

  
  

Join my mailing list here below this post to be the first to know when the course launches and to get early access to studio tips and behind-the-scenes lessons.

You might also like: The 5 Essential Tools and Materials You Actually Need to Start Oil Painting