Studio Craft: Preliminary Drawing on Canvas

Marie-Gabrielle Capet, c. 1783, holding charcoal stylus

Ask the Expert: "What's the best material to use for drawing on canvas prior to oil painting? I know a lot of people use charcoal. Can I use pencil or marker?"

A: The medium for a preliminary sketch should support the "fat over lean" principle, remain stable, and should not stain or discolor subsequent layers nor interfere with paint adhesion. A sketch medium might also be chosen because it can be easily incorporated into the painting without showing through paint (unless that's what the artist intends).

Vine and willow charcoal are widely preferred for sketching on canvas. The subtle, unbound marks of charcoal in the natural state absorb easily into subsequent paint layers with no perceptible staining. Compressed charcoal and charcoal pencils are less well suited to this application because they are denser and tend to stain more powerfully.

Medium-hardness graphite may also be used for sketches under oil paint when greater precision is desired. Contrary to a long-standing belief, graphite doesn't migrate through paint layers, but softer leads applied more heavily can tint lighter mixtures and stain whites.

Silverpoint can also be used to make very light, subtle sketches on an acrylic painting ground. Silver wire can scratch the priming, however, so a light hand is a must with this medium. Use extremely fine sandpaper to polish the stylus tip and avoid a sharp point.

While a very light coat of fixative can help reduce smudging of charcoal and graphite sketches before painting, it's important to use no more than the minimum needed. A continuous, heavy film of fixative may interfere with paint adhesion and could cause problems with future cleanings, as fixative remains permanently soluble.

Dye-based markers like Sharpie are great for utility marking, but they are particularly prone to bleeding and color migration when used on canvas. For this reason, dye-based markers are not recommended for use in permanent painting. This type of marker ink can even assert itself through completely dry paint and varnish layers.

Some prefer to work directly in paint for the initial sketch, rather than using a drawing medium first. Use of lean, fast drying colors thinned lightly with solvent ensures the initial layer provides a stable foundation for later applications. Raw umber is a particularly good choice for the first layer because it naturally promotes rapid drying and has a relatively low tint strength. For best results, avoid using slow-drying colors or those with a high oil content for preliminary sketches, especially where complex layering will follow.

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