Creating a beautiful acrylic pour painting starts with the proper foundation. Like all great works of art, a little preparation before you start slinging paint can drastically improve your results, making your art look more professional and polished. As a beginner artist, the easiest way to elevate your creations is to start painting on gesso. We’re sure you have seen the white bottles next to the acrylics in your favorite art supply store. If you’ve ever wondered what they’re for, and if you need to put one in the cart, then this guide is your new best friend. Today, we’re taking a deep dive into the benefits of gesso. What is it? Is it really necessary, and how do you use it?
If you’re paint pouring for the first time, hop over and check out our Beginner’s Guide to Acrylic Pouring for simple explanations, recommended materials, and a terms list.
What is gesso?
Gesso is essentially a primer. Historically, it was used on Medieval homes as an exterior wall covering. It consisted of a mixture of chalk, gypsum or white pigment, and a binding glue of some sort. It was known as “ditch plaster.” The mixture was very similar to Plaster of Paris and was also the base of some of the most famous masterpieces of all time. Today’s gesso hasn’t changed all that much, consisting of titanium dioxide, white chalk, and an acrylic polymer in water as a binder. The mixture dries hard, priming the surface to accept paint. When using oil paint, gesso is necessary, as the linseed oil in the paint will eventually cause deterioration of the canvas. With fluid acrylic paint, a gesso base is not mandatory, but it does still offer some benefits!
Types of Gesso
There are two grades of gesso distinguished by the ratio of pigment to filler. Student grade is cheaper and contains a higher ratio of filler. Artist grade contains more pigments. It’s more opaque and thicker in consistency. Though traditionally white and quite thin, today you can purchase clear, colored, and black gesso. Some brands are slightly thinner than paint. Others, like the popular Liquitex Basics Acrylic, are thicker than paint and utilized for adding sculpture to a canvas. It now comes in jars, squeeze tubes, and sprays.
You’ll need to experiment with brands and textures to see what you like best. Also, you’ll choose your gesso based on the type of painting you intend to create. For acrylic pour paintings, we suggest choosing a thin, liquid gesso like Golden Artist Colors Acrylic Gesso. You could also use Master’s Touch Acrylic Gesso for a more budget-friendly choice.
The Benefits of Gesso
I remember the first time I stumbled upon the miraculous goo known as gesso. I was in college and had been painting most of my life, and decided to start building my own canvases, as I was beginning to create large commission pieces. As a broke artist, the unprimed canvas rolls were far cheaper, but painting on an unprimed canvas is awful. It eats up your paint, has poor texture, and tends to crack. I bought my first bucket of gesso, and I have never painted without it again, except when going for a specific look where I want the bare canvas to show through. The benefits of gesso are numerous, and I’m going to do my best to convince you that it’s worth the extra dollars!
1. Creates a Smooth Texture
Beginners tend to use cheaper-grade canvases that are available at the local craft store. There’s nothing wrong with that, but inexpensive canvas often has a larger, looser weave pattern. This creates more distinctive pits in the canvas. One of the major benefits of gesso is that it fills these pits, creating a smoother surface. If you’re creating a forest scene with lots of texture, then this won’t matter so much. However, if you’re creating a traditional portrait, using many layers of thin paint, then you’ll want a smooth finish. For acrylic paint pouring, having a smooth base to start with helps your self-leveling paint cover more smoothly and have fewer pits.
2. Increases Paint Binding
The chalk nature of gesso provides a “toothy” grip for acrylic paint to adhere to. Unprimed canvas is slightly water-repellent due to a residue on it. By coating the canvas with two-three coats of gesso, you give the paint something to adhere to, and there is less repelling of the water-based paints.
3. Prevents Substrate Induced Discoloration
When thick layers of acrylic medium are added to an unprimed canvas, as they are in fluid painting, the contaminants in the canvas tend to discolor the paint over time. This is called Substrate Induced Discoloration, and it is most notable in white or light-colored paints. You may have noticed that your whites turn yellow over time. It’s a common problem. Cleaning your canvas and prepping with gesso will help prevent this color change.
4. Slows the Drying Time
Acrylics dry much faster on an unprimed canvas! If you’re doing your first acrylic pouring project, you want the paint to remain fluid and moveable for as long as possible. It takes time to get the hang of your pouring techniques. Learning how the paint flows and how to maneuver the canvas, palette knife, or flip cup takes practice. Having a few more minutes of drying time is helpful!
5. Protects Canvas from Damage
Unprimed canvas is thin. It tends to wrinkle, show creases over the frame, etc. It frays occasionally, and it’s difficult to clean. Remember, gesso dries hard, so it adds a level of sturdiness to the canvas that it doesn’t have in its raw form. It also seals the canvas and binds to the paint, as we have discussed, making the painting easier to clean. If your household is like mine, and there may or may not be a Nerf gun consistently shot at your wall art, a bit of extra protection is worth its weight in gold.
6. Keeps Paint Color True
If you’ve ever tried to paint a room in your house a nice greige, you probably found out rather quickly that primer is necessary. Some top coats, no matter how high quality the paint is, will pull color from underneath, turning your lovely greige into baby blue, purple, or green. To get the truest color out of your pigments, you need to start on a white base. Unprimed canvas tends to be tan or beige. Painting with gesso assures that you have a bright white base and that all the beautiful colors, you agonizingly chose, display just as you intended and not in a frustratingly altered shade.
If you’re looking for a dark, moody vibe or are aiming for high contrast, you might consider painting with black gesso! Starting with a jet-black background can produce interesting results, especially when doing a dirty pour with Floetrol or another pouring medium. The cells created will allow the matte back to pop through against the gloss of your acrylic color, creating bold pigment and texture contrast. To see this technique in action, take a look at Black Canvas Paintings-Acrylic Pouring & Neons!
7. Easier to Sketch
If you’re predominately working in fluid art, then this one won’t affect you too much. However, a regular painter often sketches their scene before painting, and many flow artists choose to as well, especially when creating a more figurative piece. Unprimed canvas is very hard to draw on. It has too much texture and absorbability. A coat of gesso transforms the canvas into a smooth surface, fit for sketching.
How to Apply Gesso
The technique you use to apply your gesso will depend on the final look you’re going for. For instance, in an acrylic flow painting, we generally want a nice, shiny, smooth finish. In this case, we’ll use a liquid, self-leveling gesso. For landscapes or abstract art with heavy texture, we want an artist-grade, opaque, thick gesso. We’ll line out the basics in the following step-by-step guide, but bear in mind that you may need to experiment based on your intended look.
Step 1: Clean your canvas.
If you’re using raw canvas, take a few minutes to wipe down your canvas with a sponge and warm water. This gets rid of the water-resistant residue, brushes off any loose fibers, and preps the canvas to bind with the water-based gesso.
Step 2: Dry brush your canvas.
Take a dry brush with stiff bristles and brush off any stray threads or dust. Starting with a clean canvas will save you time and frustration.
Step 3: Apply your gesso.
There is no right or wrong way to apply your gesso. Beginners, and those doing a pour painting, will likely use a lighter, liquid gesso. Many of these are self-leveling. You can pour the gesso on and use a wide dry brush to help move it around until you get a smooth surface. Painting on gesso with a brush is probably the most common way to do it. Most of the mixtures you find in your common art supply store will be of medium thickness. These are most easily applied with a brush. The larger your canvas, the larger the brush you will want to use.
Step 4: Dry and repeat!
Remember that you don’t want to prime your canvas in one go. You want to do 2–3 layers. So, don’t worry if it’s not perfect, and don’t make your first layer too thick. Let your first coat dry thoroughly before applying the second coat. This usually takes 15-20 minutes. If you are striving for a perfectly smooth surface, very lightly sand the canvas with fine-grain sandpaper between coats. I personally like to brush on my second layer in the opposite direction of my first. If I painted in a vertical stroke with the first coast, I will paint the second with a horizontal stroke. This helps to fill all the little pits and any brushstrokes you might have created. After your last coat, allow the gesso to dry for several hours before starting your pour.
Can I thin gesso?
If you’re a beginner, and you’re testing products, there is no need to buy several versions of gesso acrylic. Start with a medium thickness like Liquitex Basics Acrylic Gesso. You can mix in water to thin it if necessary. However, most manufacturers recommend not thinning it more than 25%. Adding more than a one-to-four ratio of water will render the polymer ineffective, and you’ll lose binding properties.
What if my canvas is already primed?
If you’re utilizing pre-primed canvases, you can get away with not using gesso, especially if you’re going to start acrylic pouring. In fact, any time you’re using acrylic paint, a primer is not absolutely necessary. Depending on the price range of your canvas, you might get a quality product that doesn’t need anything. You might also get a poorly primed canvas with gaps in the primer, frayed corners, and low-quality gesso. Analyze your canvas and your needs, and make a decision from there. Adding a layer of gesso will give you better-protected corners, a smooth texture, and a crisp, white painting ground.
Can I just use white paint?
Using white paint is an option, but it will not get you the results of gesso. They both contain white pigment and a bonding agent, but not in the same ratios. White paint with not give you the “toothy” grip of gesso or the matte, chalky smoothness. If you do choose to use white paint, choose a flat white. You don’t want a hard, slick gloss or satin as your base layer.
More Uses for Gesso
Aside from preparing your canvas, gesso can also be a great mixing medium. For instance, if I want to tint a color (mix white with a pigment), I will often use gesso instead of white paint. The chalkiness of gesso adds a matte quality. Acrylic paints tend to be glossy or satin, which works well for most pour paintings, but when you want a slightly different look, gesso can get it for you!
Gesso isn’t just for canvas either. If you’re interested in branching out to wood art, gesso helps seal it. A layer of gesso makes the wood less absorbent and prevents you from running to Hobby Lobby five times for extra paint! It also helps slippery surfaces like stone, tile, or mirrors bind better to paint. Gesso can also be used to repurpose an old canvas that has been painted on before. A coat of gesso makes it like new again!
Time to Pour!
Painting a canvas is no different from painting your bathroom, or even your face for that matter. The first layer is arguably the most important whether we are talking about all-day makeup wear or a true-to-shade accent wall. With acrylic paint pouring, we tend to focus our energy on choosing the right colors, finding the perfect pouring medium, getting the mix ratio just right, and agonizing over the best glossy sealer. Those things take some practice and analysis, but starting with a pristine, smooth, and sturdy base is a no-brainer! Pick up a tub of gesso this week, prime your canvas with a coat or two, and watch it elevate your work! Now, get to pouring people!