Bill Martin's Guide to Oil Painting
How to Draw for Oil Paintings
A complex drawing is quickly lost when the oil colors go on, so simple shapes and contour lines make the best drawings for oil paintings.
The drawing may be made directly on the canvas or it can be prepared before and transferred to the canvas.
When drawing directly on the canvas, PAINT that has been thinned with thinner is the best. Because it is paint, it doesn't need to be isolated from subsequent colors.
CHARCOAL can be used for drawing on the canvas. The charcoal drawing must be isolated from the paint layers with FIXATIVE. Vine charcoal is easier to seal with fixative than compressed charcoal.
The drawing can be made with a PENCIL on the canvas. This must be sealed with FIXATIVE before the colors go on. A pencil's point (if pushed too hard) can make small cracks in the gesso so a thin transparent layer of gesso may need to be applied to re-seal the canvas. If gesso is used in this way the fixative is not necessary.
A drawing that is going to be TRANSFERRED to a canvas is best done on thin tracing paper because the transfer will be clearer. Tape the drawing to the canvas. Transfer the drawing using carbon paper. Draw over your drawing with the carbon paper beneath it. Use a contrasting color ballpoint pen so you can see where you've already drawn and to get a consistent line size. The carbon transfer should also be separated from the paint layer with fixative or a thin transparent layer of gesso.