How to choose the stretcher bars, type of canvas and primer to get the stretched canvas that is just right for you.

While ready-made stretched canvases are a convenient choice many artists require the higher quality of custom canvases. Jackson’s offers a reasonably priced bespoke service or you can stretch your own canvas.

With a custom canvas that you make or you order you can control the depth of the stretcher bars you use (how far they stick out from the wall), the overall size of the canvas (with our stretcher bars you are limited to increments, we can’t cut to exact sizes), the type of canvas and the priming (the type of primer on ready-primed or applying the primer yourself).

Your choice of depth of stretcher bar can be made both for aesthetic and for practical reasons. The deep bars stick out from the wall further and if you stretch the canvas around and attach it on the back (like we do with all of our bespoke canvases) and paint the sides they can be shown without frames. Because they are bigger they are also stronger. This means they are an especially good choice for large canvases where the tension from the stretched canvas could warp the shape of the bars. The deep bars can also accommodate 2 centre bars in a cross shape, making a large canvas very stable. The standard depth bars are not as heavy so they are easier to manage and they are an easier depth to frame. If working to imperial or metric measurement matters to you then there is also that difference: the deep profile bars are available in 10-cm increments and the standard bars in 2-inch increments.

Deep-profile stretcher bars

We stock a good variety of canvas that should cover most artists’ needs. They can be bought by the metre or by the 10-metre roll. When measuring for your canvas be sure to account for the amount required to go to the sides or around to the back of your bars (your choice) plus the additional amount you will need to grab and pull with your pliers which you will later trim away. Also account for the different widths of some of the rolls of canvas (ours range from 72 to 82 inches wide).

There are two major fibre types used to make canvas: cotton and linen (some specialty fibres such as hemp and jute are also used for canvas). Cotton is economical but not as strong as linen and because it is a relatively new type of canvas, although it is likely to be stable over time, it just hasn’t been time-tested like the linen used by the old masters. Cotton is also more stretchy and so may not stay as tight on the stretcher bars. Linen is made from flax and is stronger because it has longer fibres. This means that it is less likely to tear at the staple line and less likely to sag after it has been stretched and primed. It also means that you can use finer and thinner linen for the same strength as heavier cottons. Unprimed cotton is usually a cream colour and unprimed linen is usually a brown because it is unbleached.

We stock two types of cotton: Cotton duck is the most common canvas in the world, it has many uses outside of art (canvas bags and so on), it usually has a noticeable weave and is quite thick. Our Italian cotton is an artist’s canvas, it is made for our industry so it has a tighter weave, a finer thread and an overall smoother surface, even the ‘medium’ texture Italian cotton is finer than the cotton duck we stock. Because of it’s low price the most popular canvas sold by the metre (and the roll) and for our bespoke canvases is the cotton duck (the 12oz primed, to be exact).

At Jackson’s we stock two major types of linen. The French linen canvas is made of smoother yarn than the Italian (less ‘hairy’), has a more regular, tighter weave and is really strong. Because the famous Artfix company uses the highest grade of flax and has amazing quality control it is a superb linen. If you paint, remove, repaint, scratch back, repaint, impasto, scumble glaze, and generally are hard on your surfaces then the French linen is a great choice as it will survive the rough treatment. Because it is so tight it can be a chore to stretch it, though and it is our highest priced canvas as well. The Italian is made with a bit coarser thread and more irregular weave but is a very good quality and we are lucky to have gotten such a good price on it, it is lower than is should be for the quality. It is also easier to stretch than the French linen.
We also stock jute for a coarse 3D texture and at a low price for its thickness.

In addition to choosing the fibre type you also need to consider the weight and the texture of the weave. Similarly to paper canvas is measured in grams per square meter (gsm) or ounces per square yard (oz). If the linen has a heavy weight then one or both of the following is true: it is a thick, tough yarn and/or it is tightly woven. Lightweight linens have an open weave and generally a fine yarn, they are easier to stretch and are more responsive to tightening procedures. The lighter weight canvases are usually used by artists who draw and/or have a light touch in their work, but even some impasto painters can use them as their paint skims over the air holes.

Unprimed French Linens

The terms ‘super fine’, ‘extra fine’, ‘fine’, ‘medium’ and ‘rough’ refer to the texture of the weave not the weight. Texture is not necessarily a guide to the weight. You can have a lightweight canvas with a rough or medium texture or a heavier weight canvas with an extra fine texture. Our 574 Italian universal primed linen is both lightweight and so fine that it feels like a sheet of paper, but because it is linen it is strong enough to stretch tightly. Claire, our canvas maker, particularly loves the 574 canvas because it can take watercolour and inks. She also likes our 568 universal primed Italian linen because it is strong and heavy enough for large scale work, has enough give to be able to stretch nicely, has a tight weave so can be used for both glazing and impasto work and she says it is beautiful.

Your final choice would be the primer on your canvas or you can choose unprimed and treat the surface yourself. Traditionally canvas is sealed (sized) and then primed with a ground for painting. Acrylic primer (acrylic gesso) does both steps in one application. A ready-primed canvas primed with acrylic primer is usually called ‘universal primed’ because canvas with this surface can be used for oil or acrylic painting. You can also get primed canvas with an ‘oil-primed’ surface just for oil painting with a creamy colour and smooth oily texture that some artists prefer. We now have a ‘gesso hand-primed surface’ available in an Italian cotton and linen that has quite a delicate dry surface that is very absorbent yet it doesn’t easily crack (though it could if handled badly). Most commercially applied primer is sprayed on, in two or three coats. Priming your own canvas will allow you to really work the first coat into the weave for good protection and then to make the additional coats as smooth or textured as you wish. Unless you sand the dried primer for a really smooth surface, there will probably be some brush mark texture.

Some artists require a clear primer because they wish to use the colour and texture of the canvas as an integral part of the painting. Our clear primed canvas is only single coated and is not suitable for oil painting without an additional coat, but is fine for acrylic painting as it is. If you wish to paint on this canvas in oils you can add an additional coat of acrylic matt medium to our clear-primed canvas or get unprimed and apply two or more coats yourself.
Note: our printed catalogue has an error: the note that says the clear-primed canvas will need a second coat to be used for oil painting has been put on the oil-primed canvas by mistake. It does refer to the clear-primed canvas.
See also: Primer and Gesso in the glossary on this site.

We will cover the procedure for stretching your own canvas in the next installment.

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to go to the canvas department of Jackson’s Art Supplies