Since oil paints are made with oils that dry to an inflexible film, it’s important to make paintings using proper techniques. With that said, however, a well-constructed oil painting can take a variety of forms.
Painting on Canvas
The Traditional Approach: Linen or cotton canvas is stretched on stretcher bars (preferably heavy-duty), coated with a sizing of rabbit skin glue, and then prepared with several coats of oil gesso, sanded between each coat.
DANIEL SMITH World’s Best White Oil Gesso is a great traditional ground for oil and alkyd paintings. It has excellent adhesion, especially on wood. An undersizing of rabbit skin glue is suggested when painting on canvas to tighten the canvas and protect it from the acids in the gesso. However, since modern gesso has a lower acid percentage than traditional gessoes, this step is considered optional; many painters apply DANIEL SMITH Oil Gesso directly to the canvas.
In fact, many conservators believe that the hygroscopic aspect of rabbit skin glue, its ability to absorb water, can lead to swelling and shrinking with changing atmospheric conditions and actually promote the sort of cracking often seen in older oil paintings. GOLDEN GAC 100 Acrylic Medium is considered a modern alternative, though it will not stiffen and tighten the canvas as well as rabbit skin glue.
A Less Traditional Approach: A modern acrylic gesso such as DANIEL SMITH World’s Best Acrylic Gesso works well on linen, cotton or polyester canvas and eliminates the need for rabbit skin glue sizing. It also works well on hardboard, wood, metal and other surfaces. Since acrylic gesso is not oily and thus “leaner” than oil paint, it is considered quite safe to paint with oils over an acrylic ground.
Our gesso comes in 8 colors so you can choose the perfect ground for your work, and it cleans up easily with soap and water. Prestretched canvases prepared with acrylic gesso are convenient, well-made surfaces for painting and can be top-coated with colored gesso if desired.
Painting on Panels
An inflexible support such as a hardboard, wood or metal panel eliminates much of the risk inherent in a flexible support such as canvas. Pre-gessoed panels protect artwork both from expansion and contraction of the various layers of medium and paint and from denting or tearing. It is safe to apply either oil or acrylic gesso directly to any type of panel. Panels such as Ampersand Gessobord are well made and convenient for painting in oils, alkyds or acrylics.
Either rabbit skin glue or acrylic gesso can be used to adhere canvas or linen to wooden panels. Lay canvas cut to the appropriate size on top of the desired panel, then, starting in the middle of the canvas, work the prepared rabbit skin glue or acrylic medium into and through the canvas, moving toward the edges, then fold the edges under and glue them to the underside of the panel using more glue or medium.
The Classic Oil Painting Rule of Fat Over Lean
Once you have a properly prepared surface, whether canvas or panel, the main thing to remember is to apply “fat” layers over “lean”—in other words, use washes or glazes involving paint thinned with solvents or mediums in the early layers of a painting, and use thicker mixtures or paint straight from the tube in the top layers.