What Is Gesso? Why It’s A Must For Every Artist

Originally, gesso was a mixture of animal glue and gypsum applied to a wooden panel so a painting wouldn’t wash away. Today, it describes any type of primer before painting takes place.

But, is it necessary? How do we know which to use?

No matter what kind you choose, gesso is a must for traditional painting. Keep reading to find out the different types of gesso, why you should use gesso, and how.

What Are The Different Types of Gesso?

There are 3 types: genuine, modern, and casein gesso. Each of these has its own qualities that determine use. True gesso and casein gesso have absorbent qualities that modern gesso does not, but modern gesso was created to work for all paints instead of just tempera and oils.

What Is Traditional or Genuine Gesso?

Traditional gesso, or genuine gesso, is a mixture of hot animal glue (usually rabbit skin glue) and gypsum applied to a stiff surface in several layers while it’s still warm. In the 14th century, gesso started as a primer for wood panels. This gesso primer allowed tempera paintings to stick to the painting support and last longer because the paint would sink in more evenly instead of unevenly in the wood grain.

If you’re interested in a more in-depth history of genuine gesso, click here.

What Is Acrylic Gesso?

Modern acrylic gesso acts as a canvas sealant, a primer, and a painting ground and comprises an acrylic polymer medium (glue) and calcium carbonate (chalk). This gesso is what most people refer to when answering the question, “what is gesso?”. It was created in 1955 to be similar to genuine gesso but more versatile.

Modern gesso is more flexible and isn’t restricted to a stiff panel. It’s also water resistant making it less likely to wash away.

What Is Casein Gesso?

Casein gesso is a balance between traditional and modern gesso. It has the absorbent surface of genuine gesso for those who use tempera or encaustic paints. Still, it contains emulsified oils, allowing it to be used on any painting support.

So How Do You Use Gesso?

Alright, now that you know what gesso is, you’ll want to know how to use it. Gesso is a primer so that your paint adheres to the surface better, but it has a couple more uses.

Use Gesso Before You Paint

You should gesso your painting surface before you start painting. That also goes for a stretched canvas and canvas panels that say they are already primed.

In production, pre-primed surfaces get a layer of gesso, but then they get a layer of sealant, making the gesso pointless. The sealant is a slippery, shiny surface and not ideal for paint adhesion. Because of this sealant, it is recommended that you gesso a pre-primed surface anyway so your paint adheres better.

When painting with acrylic, it’s not as big of a deal, but for those using oil or watercolor paints, the sealant layer repels the color instead of accepting it. That makes it hard to paint.

How To Prime A Canvas

There are a few different ways of applying gesso, and it’s really up to personal preference. With a cotton canvas or linen canvas, start in the center and spread the gesso to the corners. Starting from the corners, you can do the opposite and make your way to the center.

You may also paint it in one direction (say left to right) and then top to bottom when adding the next coat. Keep rotating the direction in thin layers until you have the desired look.

Learn more about the different methods of priming a canvas and the various techniques of applying traditional, casein, and modern gesso.

What Happens If You Don’t Gesso?

If you paint on a raw (un-primed) canvas, the bare canvas surface will soak up the paint and resemble painted clothing instead of a professional painting. Some artists do this intentionally, like Morris Louis. However, unless that’s your desired effect, gesso your canvas.

Do You Need A Different Kind Of Gesso For Oil Painting?

You don’t need a different kind of gesso for oils. Modern gesso will accept oil paints just fine as long as it’s not sanded down too much. Over-sanding will cause the paint not to stick to the gesso.

There is something called “oil ground.” Oil ground is an oil-based primer used as a layer before painting for those working with oil paints. However, you can’t use it to prime a raw canvas by itself because it’s not really a gesso that would seal and prime a bare surface.

If you want to skip the gesso and just use oil ground, you will need to apply a size onto the canvas, such as PVA. A size is a type of glue (like PVA) that seals the canvas to prevent absorption. The sealant prevents the paint from sinking into the fibers and tightens the canvas, so it doesn’t move as much while you paint.

Alternatively, you can add a layer of oil ground after you apply gesso with no issues.

If you’ve heard the term “oil gesso,” it’s important to know that it doesn’t exist. Modern gesso (acrylic) was designed to act as a canvas sealant, primer, and painting ground all in one, reducing the need to get 3 different products. “Oil gesso” refers to “oil ground,” which should not be used in place of a sealant.

Oil primer is a lot to unpack. Check out this article to learn more about oil ground and how to use it to prep your canvas for oil painting.

Using Gesso To Erase.

Yes, you read that right. Use gesso primer to erase an entire painting or apply gesso to an area you’d like to redo. When gessoing over an old image, you need to sand first so the gesso will adhere better.

This is especially true for gessoing over a painting done with oils. Acrylic will eventually peel off oil, which is why sanding is necessary when covering oil. And don’t just gesso if you’re covering an oil piece. Use an oil medium like turpenoid to “wash” the paint off and then sand once dry.

If you don’t want to risk it, this article covers an old oil-based painting with homemade oil-based ground.

Do You Need To Sand Gesso?

When using modern gesso, sanding is not required before painting. You can sand the gesso between coats if you want a smooth surface. However, don’t over-sand when using oils over the gesso, or the paint won’t stick.

For traditional or casein gesso, it’s recommended to sand between the layers of gesso once the gesso is completely dry. See here for more information on sanding genuine gesso.

Creating Texture With Gesso

As you prime your painting support, create a textured surface by applying the gesso thickly with a brush or sponge, or use a tool like a palette knife to “draw” textured areas into the gesso.

Because gesso contains chalk, it’s naturally matte. Use this to your advantage by having areas of different finishes. Acrylic paints have a shine, but if you mix in a bit of gesso, you’ll have matte paint.

If you’re into multi-media, use your gesso to prime sculpey or paper mache that you’ve added to the canvas.

Mixing Gesso With Paint

The main reason for adding a little acrylic paint to modern gesso is to create a toned painting ground. Painting over white acrylic paint has a few disadvantages, such as the white pigment showing through the paint. This is why a toned background would be beneficial.

You can purchase colored gesso which usually comes in grey or black, or you may find clear gesso to your liking.

As mentioned previously, another reason for adding paint to gesso is for a matte painting. Gesso is naturally matte because of its chalk content, so if the shine of acrylic isn’t to your liking, adding gesso fixes that.

Lastly, use gesso as a matte whitewash by adding it to white diluted acrylic paint.

What Kind of Gesso Do I Buy?

That depends on what you’re using it for and your personal preference. The best gesso out there generally works for 98% of your needs, especially when painting with acrylics.

Artists who work with tempera or encaustic paints prefer an absorbent ground, so they may choose traditional or casein gesso over acrylic.

Artists who work with oils will prefer oil ground, but remember; it does not replace modern gesso by itself. You will need at least 2 gesso layers under the oil ground or a PVA size under the oil ground.

You’ll notice that gesso (similar to paint) comes in a student grade gesso and artist grade (also referred to as professional grade). Anything labeled “student grade” is generally made with lower-quality materials because it’s intended for universal use. (Think “E” for “everyone”). When it comes to gesso, I highly recommend splurging on artist-grade gesso.

Gesso isn’t something you want to cheap out on because the purpose of gesso is to extend the life of your painting. It seals the unprimed canvas, stops the paint from soaking into the fibers, and creates extra support so the paint won’t crack or peel off.

Liquitex Professional Acrylic Gesso should serve you well. It’s artist-grade and relatively inexpensive.

Alternatively, check out this article on the best primer for oils.

Are There Any Substitutes For Gesso?

There are alternatives for gesso, but not a 1 to 1 swap. There are pre-primed canvases and canvas panels, but it’s still recommended that you gesso these anyway because the sealant cancels out its initial gesso layer.

Another possible alternative is an acrylic primer (house paint). For longevity, I don’t recommend this alternative.

All you need to do is look at the state of Jackson Pollock’s paintings. He used house paint as a cheap alternative, and despite being well cared for, every one of his paintings has peeled and needed repair.

A better alternative would be plaster or drywall mud since its properties are similar to gesso.

Can You Make Your Own Gesso?

Yes, you can concoct a gesso-like mixture that works well in a pinch. There isn’t any evidence on how it holds up with time since even commercial gesso hasn’t been here long enough to test time.

Making your own gesso is cheap and relatively easy, but it does have a higher possibility of backfiring. Homemade gesso recipes aren’t regulated and don’t have a quality check, so you’re rolling the dice on whether or not it works.

That said, here’s a recipe you can try:

• 3 parts cornstarch
• 3 parts baking soda
• 1 part glue (alternatively Mod Podge)
• 1 part acrylic paint
• And 2-3 parts water

Mix the dry ingredients separately so you don’t have lumps, then add the glue and paint. The water content is going to depend on your desired consistency. Use less water for a thicker mixture.

Other FAQs

What Is The Main Purpose Of Gesso?

Gesso is meant to be a layer between the painting support and the paint. It ensures the paint sticks to the support as well as possible.

Is Mod Podge The Same As Gesso, And Can You Prime A Canvas With It?

No, and no. Mod Podge is an adhesive and sealant. It shouldn’t be used as a primer for your canvas. However, you can use it as a size to seal the canvas before adding a layer of primer.

Is Gesso The Same As Acrylic Paint?

No. Gesso is a mixture of an acrylic polymer emulsion and chalk, resulting in a firm and matte finish once dry. Acrylic paint is a polymer mixed with paint pigment and dries flexible and shiny.

Is Gesso Really Necessary?

At least 1 coat of gesso is necessary for raw support, such as a natural canvas or wood panel. It isn’t a dire need but is recommended for surfaces advertised as “pre-primed.”

How Long Does It Take Gesso To Dry?

Modern gesso is fully cured after 24 hours and dry to the touch in as little as 15 minutes.

Wanting to know more about the drying time of the different types of gesso and when it’s safe to paint? Check out this article.

Do You Have To Let Gesso Dry Before Painting?

Unless you purposely add gesso to your paint for a matte effect, you need to let the gesso dry before painting on it.

Can I Use Paint Instead Of Gesso?

Paint doesn’t replace gesso as a sealant and primer, but you should be okay to paint straight on a “pre-primed” canvas or panel. For longevity, it’s recommended to gesso over these surfaces anyway.

How Much Gesso Do I Use/How Many Coats Of Gesso Do I Need?

For acrylic and casein gesso, it is recommended that you use at least 2 coats. Traditional gesso that contains an animal glue binder needs at least 15 coats.

Is Gesso Waterproof?

Acrylic gesso is water resistant if allowed at least 24 hours to cure fully. Traditional and casein gesso is completely water-repellant if allowed to cure fully.

How Much Does Gesso Cost?

Modern gesso ranges in price from about $10 to $60 depending on whether or not you’re purchasing student or artist grade and the quantity you are purchasing.

Traditional gesso comes in a powdered mix that starts at around $16, and casein gesso begins at $8.

The Bottom Line

Gesso is a necessary step before painting. You need to ensure the canvas will accept the paint and won’t seep into the canvas fibers.

There are different kinds of gesso, such as traditional rabbit skin glue gesso, casein gesso, and modern gesso, but for 98% of your painting needs, acrylic gesso will be fine.

And while modern gesso comes in student and artist grades, it’s better to splurge on artist grade because it will make your painting last longer. The Liquitex Professional Acrylic Gesso is a great buy because it’s a good quality gesso for a low price that will help your paintings last.

Featured Image Souce: https://gregcreates.com/improve-cheap-canvas-oil-painting/