Many projects require some prep to your surface to paint it effectively, even on surfaces that are ‘pre-treated’. From canvas to plastic, starting with a prepped surface will help your projects be their best. Let’s go over a few different things to know about the types of gesso and how to use it.
What is gesso?
Gesso is a smooth, highly pigmented professional-grade liquid paint that is one of the most important supplies needed to prepare various surfaces to receive paint. It dries hard, making the surface stiff and able to be sanded for a smoother starting surface. If not sanded it can create a subtly textured surface that is highly and evenly absorbent. When painted on top of, it has a better ‘tooth’ for paint to hold onto than untreated canvas, wood or plastic can.
Types of Gesso
White gesso is bright and ideal for when you want your colors to be the main highlight of your work. Black Gesso is great if you plan to work with much darker values in your painting or if you want to create a base that you can dry brush with lighter colors. The white and black gesso can be mixed to create a neutral gray to start from if you want to start from middle values. Clear gesso is ideal if you want to isolate what is underneath the gesso so it doesn’t affect your paint layer or so you can see what’s underneath the gesso. For example, a graphite sketch or a printed fabric.
Types of Surfaces
The most common application gesso is used for is canvas or linen. However, the number of surfaces that can receive gesso is large. Wood, paper, fabric, plaster, masonry, paper mâché, and more! What needs to be avoided is oily or slick surfaces as the gesso won’t be able to dry down appropriately or could mix with any oils and lose its ability to hold onto paint.
Application
Most applications of gesso are done with a brush. Generally, you want to use a large flat brush. Keep in mind that the denser the fibers the more gesso the brush will be able to hold, which can be especially useful if you’re working with a larger canvas. If you’re working with something smaller, such as a vinyl figure, a smaller brush also works. If you use a stiff or natural brush, keep in mind that there will be more texture left as you apply the gesso. Synthetic bristles work just as well and can be used for a smoother finish.
A palette knife is also able to be used but will not have as smooth as a result as a brush will. The main advantage of a palette knife application is its ability to create texture.
The amount of pressure used for the application is also important to keep in mind. When applying your first layer, work the gesso into the canvas thoroughly. Go in all directions to make sure the gesso is adhering to the surface from all angles. This is especially important if you’re working with something sculptural or that is already highly textured.
Let the first layer dry and, depending on how smooth you’d like the final product to be, sand the layer. If you want more texture, don’t sand or sand with a lower grit. Repeat this process of applying the gesso, letting it dry, and sanding with each subsequent layer.
You can also make the application smoother in your technique. The first layer can be rougher in order to work the gesso in but on the remaining layers be sure to lighter pressure. This will create less indentation from the brush in the gesso.
Artist Tip: If you have trouble getting the gesso into smaller crevices or over a larger surface before it begins to dry, most acrylic gesso can be diluted with water to make the first layer easier to spread.
Sanding and Ideal Grit for Gesso
Once your gesso is applied and dried, you may decide that the texture needs to be smoother. For most applications gesso dries with little texture so a higher grit can be used. (250 grit) If you want more texture, apply more layers of gesso (let it dry but don’t sand between each one) and sand with a lower grit. (60 grit or lower) How smooth or textured you want your surface is entirely up to you.
Mixing to Create Acrylic Grounds
If you’re using an acrylic gesso, you can mix in acrylic paints to create a surface that is more like an underpainting than plain white gesso can be. Common colors to mix with gesso are Burnt Sienna, Burnt Umber, and Raw Sienna. Any color can be used as a ground however, so do what performs best for your work.