- For paintings around 18 inches or smaller I prefer to use linen panels (linen on board, etc) because of the solid support the panel provides and also for the convenience as you don’t have to stretch the linen. Another option is to use gessoed hardboards (sometimes referred to as masonite). I’m not a big fan of these but I do use them on occasion. I used these a lot when I first started painting because they were very affordable.

- For painting sizes above 18 inches I prefer to use stretched linen. I purchase large rolls of primed linen and stretch the linen myself.
The reason for using stretched linen opposed to panels is because panel has a tendency to warp in the larger sizes. Stretching linen yourself will be more cost effective and better quality than the pre-stretched linen canvases you find at most art stores.

- I don’t use cotton canvas because of the even weave and the absorbency of the cotton. I find it difficult to paint on.

Two books that I regularly look to for answers:
The Painters Handbook http://tinyurl.com/284vo6h
The Artists Handbook
http://tinyurl.com/24lv9k5

Hope that helps