Quick recap on canvas: Canvas began its use as a painting substrate notably in Venice, as early as the 1400’s. Before the popularity of canvas, artists had painted their finished works for the most part on wood panels. However, the damp climate in Venice caused problems like mold and warping for wooden panels. Canvas was an attractive alternative, and was readily available in the port town. In addition, canvas was lighter in weight and could be rolled up, making it easier to transport, and larger sizes were less expensive to obtain, as opposed to wood panels. A beautiful example of early canvas painting can be found in Botticelli’s The Birth of Venus.
The Birth of Venus, Sandro Botticelli, 1486. Tempera on canvas, 67.9″ × 109.6″.
The attraction of fabricating one’s own stretched canvas: In this day and age, pre-prepared and ready-to-paint canvas is readily available and quite convenient, but fabricating one’s own support still holds certain advantages. When you stretch and prime your own canvas, you have complete control over the tautness, grain, and sealed surface of the final product. Pre-stretched canvases can be altered somewhat, such as changing the surface by adding and sanding layers of gesso, but other factors are not as controllable, such as tautness or the initial grain of the fabric.
Types of canvas: Canvas today is most commonly made from cotton, linen, synthetics, or blends of fibers. Cotton often has a more uniform, consistent texture, and is less expensive. Linen is stronger and has a more “natural” weave, sporting small irregularities that many painters enjoy. Synthetic fibers usually emulate their organic counterparts, and offer a high level of durability. Canvases in all fibers are available in varying degrees of coarse and fine grains.
Ways of mounting/stretching: Most artists prefer working on taut canvas, as loose canvas will tend to curl and warp as wet media dries on it. Canvas can be stretched across a frame or over a board. Stretching over a frame may give the canvas a noticeable “bounce,” depending on how tightly it is stretched. Frames can be made by hand, or constructed from ready-made stretcher bars that fit easily together. Canvas can also be mounted to a rigid board with strong, acid-free glue. This will create a canvas surface that does not have any “bounce,” but some artists enjoy a static surface. When canvas is stretched across a board, it is advisable to either put a coat of gesso on the backside of the board, or to make a cradled frame for the board, to discourage the panel from warping as primers and paints dry on the canvas surface.
Canvas being stretched over a frame made of stretcher bars.
The two main ways to size and prime: After a canvas has been stretched or mounted, it is advisable to size it and apply a ground. Sizing refers to a substance used to give a material more structural integrity and a protective barrier around the fibers of the canvas, and a ground or primer makes a surface more receptive to media. Sizing and priming a canvas also serves to protect the fabric from any substances that can contribute to its deterioration (such as if you are painting with oils).
Acrylic grounds: the most versatile and commonly seen grounds for canvas these days. Comes in many forms with different characteristics. Traditional acrylic gesso is available in white, black, grey or clear. There is acrylic ground formulated for silverpoint drawing, and also a variant intended for use with pastel; it has pumice in it for gritty texture. Additionally, some manufacturers have created “watercolor grounds,” which are acrylic-based grounds that create a surface that is absorbent enough to be suitable for use with watercolors. Acrylic grounds will both size and prime the canvas.
Oil-based grounds: should only be used in conjunction with oil-based paints*. Before the application of an oil ground, the canvas needs to be sized, either with a rabbit-skin or an acid-free PVA glue. Rabbit-skin glue makes for a stiffer canvas, but PVA glue is more chemically stable and less likely to crack over long periods of time. After sizing, the oil ground may be applied. However, a properly sized canvas has adequate protection that it may be directly painted on with oil paints. Oil-based grounds yield a much stiffer substrate than acrylic-based gesso.
*Paints that are water-based (like acrylics and watercolors) will not adhere well to oil-based grounds; peeling and cracking are inevitable.
The final product: Depending on how it is prepared, one stretched and primed canvas can vastly differ in its finished properties from the canvas of another artist. One canvas may have a relatively* looser bounce and a heavily pronounced texture, whereas another canvas may be taut and smoothed to the point where it is almost like a flexible panel, more in line with the canvases of the Old Masters. One is not better than the other, some are just more appropriate for certain applications than others. The choice on substrate properties is developed through specific project needs, experience with materials, and the artist’s personal preferences.
* Please note… If a canvas is too loose, it may not prove to be supportive enough and the paint could crack.