Cotton duck is the most widely used support for most people from beginners to many established professional artists. The cotton duck comes in different "weights" eg 8, 10,12 or 14oz (weight per square yard - which relates to the strength of the material). Different weaves can affect the strength of the material.
Linen is considered by most artists to be the best natural fibre for canvas. It is made from the flax plant, the fibres of which have greater natural strength and also longer length than others. Most people who have used linen, especially for oil painting, find they prefer it"s more interesting, slightly less regular texture. Some say it posseses more "depth" or character.
Almost any cloth can be used as a painting surface. Some artists are using cloth from synthetic fibres, or blends of natural and synthetic fibres. Hemp and Jute have been popular in the past. Velvet gives an interesting effect.
These cloths are sold as either "unprimed", meaning they have had no sealer/ gesso put onto them. Unprimed canvas is for those who prefer to use their own gesso, either home-made or bought.