Unprimed canvas weight is often given in ounces because historically, canvas was primarily produced and sold in the United States, where the imperial system of measurement (ounces, pounds) is used. The weight of unprimed canvas is usually expressed in ounces per square yard eg 12oz.

Primed canvas weight, on the other hand, is usually given in grams per square metre because it is more commonly produced and sold in Europe, where the metric system of measurement (grams, kilograms) is used. Primed canvas weight takes into account the weight of the canvas as well as the weight of the primer that has been applied to the surface.

The weight of primed canvas is thus higher than that of unprimed canvas due to the added weight of the primer. Using grams per square meter is a more precise way of measuring the weight of primed canvas but with the vagaries of double or triple priming it can be difficult to tell what you are getting from a single number.Personally, I think it is best if the primed and unprimed weight can be quoted. because it takes into account both the weight of the canvas and the weight of the primer.

Most of our stretched canvasses are 10oz canvas that has been primed to a total weight of 380gsm.Our heaviest linen is 13oz unprimed and 680gsm primed which makes a very sturdy surface to paint on.

As a general guide, anything under 10oz unprimed weight is a bit flimsy for quality art painting.However if glued to a board then a weight of 7oz is fine.Stretching works of 1m plus should really only be done with a minimum of 12oz unprimed weight eg our extra heavyweight stretched canvases.

One final caveat – linen is stronger than cotton so a fine weave quality 10oz linen is approximately equivalent to 12oz canvas.

Happy painting!