Canvas can mean different things to different people. In the context of painting, the word “canvas” means a fabric used as a painting surface. The difference is that sometimes the canvas is made from cotton fibres and other times from linen fibres. Each material is worth looking at in more detail.
Cotton
Cotton is a soft, fluffy fibre that grows in a boll or protective capsule around the seeds of cotton plants. The plant is native to the Americas, Africa and India, and is most often spun into yarn or thread to create a soft, breathable textile. The chances are you are wearing some cotton right now.
The advantage of cotton to you as an artist is that it is affordable and stretches very easily. A properly prepared cotton canvas will last a long time, and is the most popular surface for oil and acrylic painting, especially among students – although it is considered too flexible for very large paintings. It is classified according to its weight and surface texture.
When it comes to tightness, cotton comes out on top. It is possible to stretch cotton tighter than linen without straining the wooden support around the canvas, and a heavy-grade cotton can make up for its lack of strength and weight.
Linen
Linen is strong and durable, and remains the preferred surface for many artists. But it is expensive. It is made from the fibres of the flax plant and top quality flax is harvested mainly in Western Europe. If you want your painting to last then a linen canvas is a sound investment. The threads that make up linen, known as the warp and weft threads, weigh the same, which means they are less prone to expansion or contraction due to moisture.
Linen retains its natural oils, which helps to preserve the fibre’s flexibility and stops the canvas from becoming brittle. It is also regarded as having a more “natural” weaved finish than cotton. A variety of textures and weights are available in both rough and smooth finishes.
Because of its strength, linen holds up to a heavy painting hand and does not become slack as easily as cotton canvas.
Priming and sizing
Priming your canvas by applying a layer or two of gesso to the surface, whether cotton or linen, will help in a number of ways. The white layer of gesso – one of the most popular primers – beneath the visible surface of a painting has the effect of making all the colours in the painting a little brighter. An unprimed canvas can also soak up all the paint, causing some of it to disappear into the canvas or clot up on the surface of it.
If you are going to prime a cotton canvas and want to use either oil or acrylic colour then an acrylic gesso primer is generally used.
Linen can be difficult to prime and stretch properly, but once you have mastered this it offers the smoothest and stiffest painting surface. When priming a linen canvas you can use an acrylic primer or an oil primer. Acrylic primer are less expensive, and you can then use both acrylic and oil colour on the primed surface.
Sizing
If you are using an oil primer on either cotton or linen then the surface must first be “sized” with rabbit skin glue or polyvinyl acetate (PVA) size. Sizing is the process that fills the pores in the surface with glutinous material and helps to stop fluid leaking through. It also helps stiffen the fabric. If oil colour is applied to an unsized canvas the oil will eventually weaken the fibres and the image on the surface may fade.
It is important to remember that if rabbit skin glue or neutral ph PVA size is to be applied to either cotton or linen, the canvas must not be stretched too tightly. Both sizes are very fluid and they will cause the fabric to contract to such a degree that the stretcher bars may warp.
Primed canvases
You do not have to size and prime a canvas yourself. Winsor & Newton offers acrylic-primed cotton and linen pre-stretched canvases in both regular and depth stretcher bars (13/16″) and deep edge (1″). Cotton canvas is available in 10 oz and 11 oz per square yard weight, while linen canvas is offered in 12.6 oz per square yard weight. Sizes range from 4″x4″ to 48″x60″.
If you simply want to stretch your own canvas but would rather not do your own priming then Winsor & Newton offer rolled cotton canvases that come ready primed. If you still want to do your own priming, unprimed canvases are available as well.
Canvas boards
Winsor & Newton Artists’ Canvas Boards are great for studies and art school projects and come ready sized and primed in various sizes. They can be used with oil, water mixable oil, alkyd and acrylic colours.
Fine detail
If you are working on subjects such as portraits, still life, and other detailed work, Winsor & Newton Fine Detail Cotton Canvas is an ideal surface. It comes sized and primed, giving you an outstandingly smooth surface for oil, alkyd and acrylic colour.