Painting & drawing blog

HOW TO CHOOSE A CANVAS

Tips for beginners in oil and acrylic painting

If you’re new to painting you fortunately don’t have to stretch, size or prime your own canvas! Art shops and online stores sell a myriad of pre-prepared canvases in different shapes and sizes which are all ready for you to work onto. There are some different options to choose between, and you’ll also decide how much you want to pay for your canvas.

A stretched canvas

In this post we’ll look at all the features to look out for when buying a pre-stretched and pre-prepared canvas in an art shop. We’ll also cover ‘canvas boards’ and ‘canvas panels’, and consider when it might be useful to work onto these surfaces as an alternative to a traditional canvas (you can use the links to jump straight to those sections if you like) There are no paid links in the post, just my independent suggestions for useful products or suppliers.

STRETCHED CANVASES

Faced with the vast range of stretched canvases that are available you’ll likely wonder why some are more expensive than others when they pretty much look the same! Only a few differences will be obvious on casual inspection. You can buy extremely cheap stretched canvases these days in places like Hobbycraft and I’ve even seen them in some homeware stores. However if you buy a canvas outside a proper art store it’s going to be of a quality even below ‘student’ grade and may not even be made from pure cotton but instead from a blend of cotton and cheap synthetic fibres.

In an art shop or online store you’ll have a choice between a ‘student’ or ‘beginner’ ranges and ‘artists’ or ‘professional’ grade canvases. These will vary considerably in price and sometimes the cost is the only way to tell the difference between them, although student ranges may be given a name such as ‘Essentials’, ‘Academic’ or ‘Studio’ which will tell you that it’s being marketed at beginners or as a cheap ‘practice’ canvas. Better canvases may be called ‘Premium’ or ‘Professional’, although once again if their title doesn’t give a clue then their price may be the only reliable guide to their quality.

Stretched canvas

Let’s now look at some of the obvious differences between different sizes, thicknesses and materials before considering which other qualities that a good quality canvas may possess whilst a cheaper one may lack.

The size

In the UK canvases are most commonly measured in Imperial (inch) sizes but some are sold in centimetre measurements. Cheap canvases may sometimes conform to European the ‘A’ sizes of A4, A3 and so on. If you want to work on a rectangular canvas my advice would be to avoid anything with rather a ‘letter-box’ shape because the proportions aren’t very pleasing. For example a canvas whose dimensions conform to an ‘A4’ size will be much more rectangular and less satisfactory than an 8×10 inch size.

The thickness and the stapling

Next you’ll need to decide what thickness of canvas you prefer, from a regular canvas with a depth of a couple of centimetres, to a chunkier deep-sided canvas of up to about 4cm. If you intend to hand your canvas straight on the wall without framing it then a thicker canvas would look much better, but if you do intend to frame your painting then a thinner canvas is preferable. If you are going to hang your painting straight onto the wall unframed (or prop it on a mantelpiece), make sure the canvas fabric has been stapled to its wooden stretcher on the back rather than on the sides so that the staples aren’t visible: this is known as a ‘gallery wrap’. The canvas in the picture at the top of the post is an example of this.

Cotton canvas vs linen

Canvases will usually be made from either cotton (known as ‘cotton duck’, from the Dutch word ‘doek’ meaning cloth) or linen, or occasionally from ‘poly-cotton’ which is cotton with a small percentage of polyester added to it.

Cotton and linen canvases
Photo credit: jacksonsart.com

Cotton duck is the least expensive of the three and linen is the most expensive because it’s less common and is harder to process into fibres and then stretch evenly over a frame. Cotton fibres are relatively thick and whilst you can certainly find a ‘fine’ textured cotton canvas, it’s harder to find an ‘extra fine’ option in cotton. Linen canvases in contrast come in a wider variety of weights and textures, although typically you’ll only find them with fine or medium textures and rarely in the ‘rough’ or ‘extra rough’ varieties that are easily obtainable in a cotton canvas.

Linen canvases are darker in colour and are particularly strongth and usually especially smooth. They are popular with professionals for their finer threads, tight weave and for the natural linseed oils present in their fibres which create a good degree of elasticity. That doesn’t necessarily mean that linen canvases are desirable for everyone however, it’s really a matter of personal preference and there is certainly nothing wrong with a good cotton canvas. Linen canvases are slightly more stable because the linen fibres are less absorbent than cotton, giving a greater resistance against mould and mildew and making them less prone to contracting and expanding when exposed to moisture in the air. This may be a factor if you’re looking for a canvas with the best archival qualities.

Poly-cotton blend canvases are less common than cotton duck or linen, although Jacksons stocks one or two. They are more stable than plain cotton canvases as the polyester content gives them extra strength and ‘spring’ and helps them to stay tight. A poly-canvas can offer a smoother (sometimes ultra-fine) surface because its threads are finer and are woven more tightly. The surface is very uniform with little irregularity, and this may be desirable to some but others might prefer the natural variation in the texture of a completely natural fibre canvas.

The weave and the weight

If a brand of canvas doesn’t clearly state what sort of texture it has, it is likely to have a medium texture (cotton canvases) or fine (for linen canvases). Often however a range of canvases will be available in a choice of textures from ‘no grain’  which is nearly as smooth as paper and ‘extra fine which will have a minimal texture, through ‘moderately fine’, ‘medium’ and ‘rough’ to ‘extra rough’ which will give you an extremely textured finish. The distinction relates to how tightly the fibres have been woven together.

As we’ve already mentioned, if you want the smoothest weave for your canvas painting so that the texture of the fabric barely shows through your paint layers then a linen canvas or a poly-cotton canvas may be preferable to a cotton duck canvas because it will be more tightly woven and is more likely to be made from finer yarn. Extra fine linen canvas is sometimes known as ‘Portrait Linen’ because for a very detailed portrait you would likely want a very smooth surface to paint onto. In contrast for a large, textural painting you may want to make a positive feature of the way that the irregularities in a rough weave shows through the paint and a rougher cotton canvas might suit you better.

Although the weight of the canvas will often be given, it’s not a clear-cut guide either to the texture or the quality of the canvas. In general you’ll find finer textured canvases being made from finer yarn and coarser ones from thicker yarn, but there is a degree of variation between different brands and so for example a heavyweight canvas with thinner but more tightly woven threads could be heavier than one made from thicker yarn that’s more loosely woven.

Linen canvases are more lightweight than cotton ones but as we’ve already discussed they are likely to be stronger. Any priming that has been applied is included in the given weight of the canvas and some canvases will be more heavily primed than others. As a general rule, you’ll find that ‘student’ grade canvases will typically be light despite being made from cotton due to a combination of loosely woven thinner threads and a minimal number of priming layers. Therefore whilst a heavier canvas isn’t necessarily better (although heavier will obviously be stronger, which may be a factor if you want your paintings to be as archival and long lasting as possible) it does make sense to avoid a very light canvas if the brand is particularly cheap and basic in quality.

The stretcher bars

The stability of the wood used to make the stretcher bars that the canvas fabric is wrapped around is important to how well it will maintain its shape amidst climactic changes of heat, cold or humidity. The quality of the stretcher is something that will vary depending on how expensive a canvas you buy. A cheap canvas is likely to have stretchers made from a soft wood such as pine which have been given minimal strengthening treatments. A better canvas will use kiln-dried stretchers to create maximum warp resistance and will be properly ‘finger jointed’ at the corners. Many layers of lamination will be applied to protect it against bowing and to discourage acid transfer to the canvas from the wood: a problem known as ‘stretcher burn’. An ‘acid-free’ label on a canvas would imply that the wood of the stretcher has been well laminated.

Canvas stretcher bars

Photo credit: jacksonsart.com

The most expensive canvases may be made with hardwood or aluminium stretchers, or with wood that’s been reinforced with aluminium inserts. Whatever material a stretcher is made from, it should have a rounded profile so that the canvas is smoothly and evenly stretched over it and doesn’t make an imprint into the fabric. Above you can see an example of some stretchers by Jacksons with suitably softened edges. This is something that the very cheapest canvases may lack.

The tightness of the canvas

One very obvious problem you’re likely to encounter with a cheap canvas is a certain slackness where the canvas hasn’t been pulled tightly enough over the frame. This may not be immediately apparent, but you may notice it when you start painting on it. It’s most likely to be a problem with a larger painting where the weight of the paint layers can start to loosen the canvas fabric.

Not everyone values the tightest possible canvas and some may prefer a bit of slack, but in general most people prefer to paint against a fairly taught surface that resists the pressure from your brush. A decent quality canvas should come with a little bag of ‘canvas keys’ or ‘wedges’ stapled to the back of the frame (ironically it’s the very cheapest canvases that have the most need of tightening that sometimes do not come with keys included) The keys are small pieces of wood that you can insert into slots in the corners of the canvas frame and tap in with a hammer to tighten it up. Jacksons has a good tutorial on how to use the here

Canvas wedges

Winsor & Newton’s basic but respectable ‘Classic’ range of frames come with keys, however their more expensive ‘Professional’ range of canvases come with an innovative device that they call a ‘Pro stretcher’. This fits easily into the slots at the reverse of the frame and has a screwhead that you simply tighten with a screwdriver to adjust the tension to your liking. Here’s a still from their video demo.

Pro stretcher

Priming

Most pre-stretched canvases (and canvas boards and panels, which we’ll cover below) will also be pre-primed.  Priming serves a number of purposes. It protects the canvas by providing a barrier between the fibres and the paint layers so that the paint doesn’t sink straight into the fibres and rot them, and it ensures better adhesion of those paint layers. This is particularly important for oil paints where the slow drying oil content would cause acid-damage to the canvas fibres if they weren’t protected. Technically you don’t absolutely have to prime a canvas in order to paint onto it with acrylic paint: however, priming also smooths the surface to cover irregularities in the weave and tightens the canvas, adding a rigidity and stability to the paint layers which may both be advantageous to the acrylic painter too. A white priming layer will limit the absorption of acrylic paint into the fibres and give it maximum reflectivity and vibrancy.

Priming a canvas

Most canvas labels will proudly state that the canvas has been ‘Triple primed with three layers of gesso’. This is a somewhat misleading description that confuses many beginners. True gesso is a ‘glue ground’ which is a combination of an animal skin binder (usually rabbit skin glue) and gypsum. It was was used since at least the medieval period to give a preparatory undercoating to wooden panels, the traditional support for oil paintings at the time. When canvases gained in popularity, gesso was also applied as a primer to these too in a thin layer under another layer of oil. These days it is recognized that rabbit skin glue when used on canvas as a size or within a gesso is a major cause of cracking in oil paintings and it is less commonly used.

Therefore, when you see ‘Triple Primed with Gesso’ on a canvas label today, it doesn’t refer to gesso at all but to a modern acrylic primer which is an acrylic resin mixed with a white pigment and a filler such as chalk. This is usually known as ‘Acrylic Gesso’ or simply as ‘Gesso’, but it’s really nothing of the sort. Some manufacturers such as Jacksons instead describe canvases coated with acrylic gesso as being ‘Universal Primed’ because a canvas primed with acrylic gesso can be used for painting with either acrylic or oil paints.

Any canvas which doesn’t state that it is ‘triple primed’ – which is really a minimum – is best avoided because the priming layer will be so thin that the paint may not adhere well and it may feel overly absorbent or too slick and shiny, depending on the acrylic priming used. If it’s really thin, you may get an uneven, inconsistent surface and the canvas tension may feel too loose. Many people who do buy commercially primed canvases prefer to add further supplementary coats of primer on top and sand each one down before they start painting.

Some artists working with oil paint believe it is better to paint with an oil-based primer instead of an acrylic one due to some uncertainty about the future stability of the paint layers applied on top – a question that hasn’t been satisfactorily answered yet. You can quite easily source ‘oil primed’ linen canvases if this is of concern to you. However most beginners will be perfectly happy with a canvas primed with a universal acrylic primer.

Unprimed canvases

Some people prefer to paint straight onto canvases which are unprimed, allowing the colour and texture of the fabric to remain visible in parts. However whilst a priming layer may be omitted it’s still vital for a canvas to be ‘sized’ in order to protect it from rotting so if you want to do this, look for a ‘Clear Glue Sized’ canvas, sometimes also known as ‘Clear Gesso’ priming. Unprimed canvases like this will usually be made from linen, which has a darker colour than cotton. The size applied may be rabbit skin glue, or a universal acrylic primer – check the manufacturer’s information online if you want to know which.

Clear glue sized canvas

‘Belle Arti’ Universal Clear Glue Primed linen canvas. Photo credit: jacksonsart.com

CANVAS PANELS AND CANVAS BOARDS

These options are for people who prefer to paint onto a harder surface than a canvas but still want the texture that a cloth canvas provides, or who are simply seeking a cheaper alternative to a traditional stretched canvas. Canvas boards are made from a layer of canvas which is glued to a thick piece of cardboard and trimmed all the way round (known as ‘sheared edges’). They are designed for working outdoors ‘en plein air’ (due to their lightness and portability), for quick studies, or just for people who prefer to paint on a rigid board but with a canvas texture. Often sold in multipacks they may be marketed to students as an economical alternative to stretched canvases, in which case their quality will be fairly low with a thin lightly primed canvas layer stuck to a flimsy board that may warp easily. They are usually very absorbent.

Canvas boards

Due to the quality of materials that canvas boards are made from, you are unlikely to find many that meet the best archival standards. Jacksons sell a variety of slightly better quality canvas boards made with a choice of cotton or linen canvas and universal or oil priming, some of which are made with MDF rather than compressed card.

Your best bet for something stronger and with better archival qualities is a ‘canvas panel’ which will be made with a tempered hardboard core. Sometimes the terms ‘board’ and ‘panel’ are used a little interchangeably so price will be your best guide as to which is which, since hardboard panels will be considerably more expensive than cardboard ones. Canvas panels are sometimes also sold as ‘Gessoboard’ because like canvases they will typically have been treated with a universal acrylic primer. You can also find clear glue primed panels that are unprimed.

Canvas panel

Canvas panel. Photo credit: jacksonsart.com

Like canvas boards, not every hardboard canvas panel you’ll come across is properly archival and very good quality ones can be difficult and expensive to obtain in the UK. Jacksons’ panels use a pH neutral glue to stick the canvas to both their boards and panels, in order to protect the fabric from acid damage leaching from the backing board. A company called Fredrix also make good archival linen panels which are available online.

CATEGORIES

DRAWING PEOPLE

DRAWING ANIMALS

DRAWING MATERIALS

OIL PAINTING

WATERCOLOUR

PAINTING MATERIALS

FRAMING

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