Canvas

Using canvas for portraits

Canvas used for painting is made from either Linen or Cotton. Linen canvas is made from flax and comes in various surface textures. It can have a very smooth texture, perfect for detailed work or a much rougher surface for a broader style of painting.

Cotton canvas has a similar range of surface textures and is more widely available. It can also be purchased as a ‘prepared’ canvas glued to a backing board. The board is usually a thick cardboard and comes in standard sizes. However, some artists prefer to prepare their own onto a more substantial backing board, usually wood. This also has the advantage of a firmer surface to work on and they can cut the board and canvas to any size.

The standard canvas is commercially available as a prepared material stretch over a wooden frame, known as a stretcher. This frame has adjustable corners that come with wedges that are tapped into the inside corners of the frame. These take up any slack in the frame and make the whole surface very taught.

Canvas can be bought as a ‘prepared’ surface or as a natural cloth material. The ‘prepared’ surface means that the canvas has been primed and treated so it is ready for painting. For untreated canvas, the artist has to prepare and treat the canvas before painting can commence. The first step is to ‘size’ the canvas. This is basically a layer of gelatine or animal glue to seal the fibres and prevent the penetration of the paint. The oil in the paint becomes slightly acidic as it dries and would damage the canvas over time, so the size would prevent this from occurring. The whole surface is then painted in a few layers with Gesso, which is a primer especially formulated for painting with oils or acrylics. The modern gesso is made from Titanium dioxide, calcium carbonate that is a form of chalk and finally bound together with an acrylic polymer medium.