If you require a particular size or a type of canvas that is not available as a ready-made you may wish to make a custom canvas. Because the bars and canvas are usually more heavyweight, the quality will be better than you can get in most ready-made canvases. Jackson’s offers a reasonably priced bespoke canvas stretching service or you can stretch your own canvas.
- Do you need to make a custom canvas?
- Summary of method and time it takes for each step
- The characteristics to consider when planning your stretched canvas</a
- The tools required for stretching a canvas are straightforward
- Choosing the stretcher bars for the frame
- Choosing the canvas
- The amount of canvas
- Assembling the stretcher frame
- Stretching the canvas
- Folding the corners of a stretched canvas
- Priming the canvas
- A canvas just as you wanted it
- Canvas on a panel
- Artist Canvas at Jackson’s Art
Do you need to make a custom canvas?
The first time you might consider getting or making a custom canvas is when you can’t find the size you want. We stock ready-made canvases in a wide range of sizes in 10cm or 2-inch increments starting at 7x10cm and going up to 120x160cm and 100x180cm. Jackson’s Premium Cotton Canvases also come in special Golden Ratio sizes (*see the note at the end) as well as the standard ratios. But not every size imaginable is available. If you need an unusual proportion (long and narrow for instance), a size between those available, or if you wish a particular canvas material or heavier stretcher bars that are not available in a ready-made, you can order a bespoke canvas made for you. This is done at a fair price by skilled specialists in our Bespoke Canvas Department. But you can save money by stretching your canvas yourself, using the same bars and canvas as they do in our Bespoke Canvas Department. You can get 39 50x60cm standard depth canvases or 6 150x200cm deep profile canvases out of a 210cm wide full 10m roll of canvas, including wrapping the canvas around to the back and trimming off the excess you use to grip and pull. The more you do it, the better and faster you will get. It’s a great way to spend the coldest days of the year too – many artists set aside a few weeks in the depths of winter for preparing surfaces, as you get a little workout and it helps to keep you warm.
Summary of method and time it takes for each step
1. Knock together stretcher bars with a mallet – up to 5 minutes for a small canvas, up to 20 minutes for a very large one with two cross bars to fit in (some time is saved if you have a helper for the large ones and you might need a stepstool).
2. Do the calculation, measure, mark and cut canvas piece with large shears – less than 5 minutes per canvas, even faster when you have lots the same size.
3. Lay stretcher bar frame on canvas piece and square it up – less than 5 minutes for a small canvas, up to 5 minutes for large canvases.
4. Stretch canvas, including neatly folded corners – up to 10 minutes for a small canvas, up to 30 minutes for a large one.
Total time: less than 30 minutes for a small canvas and up to an hour for a large one.
Part of the difference is that a small one is on a table and you can stay in place and turn the canvas. But a very large canvas needs to be on the floor or a very large work table and you have to move around it.
The characteristics to consider when planning your stretched canvas
- dimensions (you may want a very specific size or unusual aspect ratio)
- depth of canvas (the thickness, how far it projects from the wall)
- the quality of stretcher bar (Professional wooden, Museum wooden, Museo Alu-Pro wood and aluminium)
- if you choose to add a centre bar or cross bars for extra strength
- the type of canvas (cotton, jute, linen)
- the weight of canvas (in grams per square metre – gsm, or ounces per yard – oz)
- the brand of canvas (Artfix (French linen), Claessens (Belgian linen), Belle Arti (Italian linen and cotton), Jackson’s (Indian cotton)
- the orientation of the canvas – do you plan to use it horizontally (landscape) or vertically (portrait) – this will affect how you fold the corners
- the priming (un-primed, universal primed, oil primed, glue sized), after it is stretched if you wish to you can prime it with a primer with the characteristics you require, either on un-primed canvas or by adding another coat of the primer of your choice to a universal primed canvas. Watercolourists can add a coat or two of an absorbent ground and pastel painters can add a layer of pastel ground.
The tools required for stretching a canvas are straightforward
- a rubber or plastic mallet or a hammer with a piece of wood (to assemble the stretcher bar frame without denting it)
- a measuring tape or metre stick (to measure corner to corner to ensure the stretcher frame is square)
- a pencil and straight edge (for marking your canvas to cut)
- a strong pair of scissors or a utility knife and straight edge (to cut your piece of canvas off the roll and to size)
- a pair of canvas pliers (to pull the canvas tight)
- a heavy-duty staple gun and staples – manual or electric – (to attach the canvas to the back of the stretcher frame) or canvas tacks and hammer (to attach to the sides of the stretcher frame)
- a staple lifter (surprisingly useful if you need to remove staples that aren’t quite right to adjust the tension)
- a tack hammer (for tapping in staples that stick up and for tapping in wedges)
You can use staples or tacks on the side or back to hold your canvas taught. The contemporary fashion is to staple on the back so the canvas is clean to view on the sides. This is sometimes called a ‘gallery wrap’ as it makes the painting presentable on a gallery wall even unframed.
You can use a hammer and canvas tacks, a manual staple gun or an electric staple gun. For these canvases, I used the most common choice: a manual staple gun. The guns come in a few styles – light to heavy duty – this is usually a matter of a metal or plastic body. They usually take a few sizes of staples – the same width but of varying depths. I have successfully used 4mm, 8mm and 10mm staples for stretching canvas. We have just added to our stock a good electric staple gun from Tacwise at a good price. Stretcher bar wood is pretty hard and I have come to appreciate my electric staple gun, it saves my hands from the workout of pressing the resistant spring handle and the recoil of the staple gun if I’m stretching all day. But many people have no difficulty with a manual staple gun.
How to load a manual staple gun
I am including this because it is a common issue. If you load the stapler in the way that looks obvious and then try to staple but nothing comes out or if you can’t get the spring loader to push back in, you’ve loaded it on the wrong side. It looks so much like the strip of staples should go over the top of the staple insert bar but really the staples go in the gap in the bottom of the body that is created when you pull the spring loader back. Turn the stapler over and load it in the bottom laying the strip in on the flat side and push the spring loader in until it clicks. The staples should be facing the way they will come out.
A staple lifter is an indispensable companion to a staple gun. You will need to remove staples at some point in the process: the temporary staples that you use when stretching linen, the staples you may have put too far towards the corner so you then can’t create a fold and you may wish to adjust the tension and need to take a few out to do this. At some point you may need to remove a painting completely from the stretcher bars if you wish to roll it for storage, shipping or to re-use the stretcher bars (rolling up is not great for the health of the painting, but it is sometimes necessary). This unassuming little tool makes it so much easier.
Most staplers have a setting to adjust the force of the staple: light (min), medium and heavy (max) pressure. Each is harder to pull as the spring is under more pressure. Light is very useful for temporary staples like you might use on the corners when starting a large linen canvas or for holding corner folds temporarily – they are easily removed. Heavy pressure staples are hard to remove so are great for key areas such as the centre staples that you start with, as they won’t come out when you pull the canvas next to them. But the heavy pressure setting is hard on the hands as you have to squeeze really hard. Medium is in between. So if I am using a manual staple gun I often use the heavy pressure setting (max) just in a few key places and the medium setting for the rest. But if I have the option, my preference is for an electric staple gun as it is less strain on my hands and wrists as the pressure is almost effortless and it has a safety feature.
Choosing the stretcher bars for the frame
Our stretcher bars:
1. Quality – Professional wooden (strong), Museum wooden (stronger because of the layers of laminated wood), Museo Alu-Pro wood and aluminium (strongest because of the aluminium, and it still has a bit of wood to staple the canvas to).
2. Depth – we have seven depths to choose from: 18mm, 21mm or 43mm (Professional wooden), 20mm or 35mm (Museum wooden), 25mm or 45mm (Museo Alu-Pro wood and aluminium). This is how far the painting will extend from the wall.
3. Size – you may wish a standard aspect ratio like 3:4 (120x160cm) or 4:5 (120x150cm) or you may wish to choose a ratio based on the Golden Ratio 1:1.618 (120x194cm) or any other size that fits your subject matter or idea best. All of the seven depths of stretcher bar we do are in metric measurements except the 18mm and 21mm which are in inch lengths. For very large sizes you will need to choose thicker bars for strength, so the thinner bars aren’t available in the largest sizes. Jackson’s can cut all three types of stretcher bar to bespoke lengths – this needs to be done by phone. The price is the price of the bar that is one size larger on our price list as yours will be cut down from that – plus £10 per stretcher frame for the four new corner dovetail joiners.
4. Centre bars – Decide if you want a centre bar or cross bars for extra bracing. Stretching canvas puts a lot of tension on the bars and can pull them out of flat and give you a warped canvas (so that one corner is kicked away from the wall, a warped canvas will rock if laid flat, it will not have all four corners on the floor at the same time). Framers have told me not to rely on framing to flatten a warped canvas because the frame is not strong enough and will probably be pulled apart under the pressure. Bracing on the back gives added rigidity as well as handy handles for carrying a large painting. Making sure the tension is even when stretching the canvas will also be important to prevent the twisting of your bars. The two thinner bars in the Professional range only allow one centre bar while the 43mm bars have two slots for centre bars to pass one over the other, so you can have cross bars. The Museum bars have cross bars with a notch in the centre for the bars to sit flush like a lap joint. The Museo Alu-Pro centre bars are all aluminium and need to be affixed with special hardware, they come in primary and secondary sections depending on if you need just a single centre bar or a second cross bar.
When using a single centre bar the most stable construction is to have the centre bar going across the width, not the length – so the centre bar should be the same length as the shorter side of the stretcher frame. Just in case you were wondering – you do not need to do any maths when ordering centre bars, they may be smaller to fit inside the frame, but they are labelled for the side bar they need to match, so just order the same size centre bar as your shorter stretcher bar.
Some artists glue the corners of their stretcher bars but then if humidity changes the tension of your bars or canvas and you get a corner sag if you’ve glued it you cannot use the corner wedges (keys) to spread the frame a millimetre or two to get even tension again. You want the stretcher frame to stay adjustable.
Read more in our canvas blog article – Everything You Need to Know About Stretcher Bars.
Choosing the canvas
You can compare some of the canvases Jackson’s stock by ordering sample pieces of the Claessens Linen or Belle Arti sample books. Many artists try painting on different canvases, primers and grounds until they find the surface that works best for the painting they are doing. The surface qualities can profoundly affect some artists’ painting.
1. Material – Linen, cotton, jute
2. Weave – The ‘No Grain’ texture is almost as smooth as paper and is great for portraits where paint skipping over a weave pattern might interfere with the likeness of the figure. You can choose from no grain, extra fine, fine, medium, rough and extra-rough.
3. Weight – The heavier the weight the more tension it can take, so for very large stretched canvases you might wish to choose a heavier canvas.
4. Priming – Un-primed, universal primed, oil primed, glue sized.
5. Brand – Artfix (French linen), Claessens (Belgian linen), Belle Arti (Italian linen, cotton and poly-cotton), Jackson’s (Indian cotton).
In addition to the great strength of linen and the fantastic surface, it gives for painting linen has to cache among art collectors and so artists will usually mention in their materials list that it was specifically linen they painted on. Also, there is something poetic about painting in oils made with linseed oil on a linen canvas – both being made from the flax plant.
When stretching linen be sure to use very strong stretcher bars because by the time you get it tight there is a lot of pressure on the bars. Light-duty bars are easily warped out of shape. Also, make sure the corners of the stretcher bars have no sharp points. These should be sanded off before stretching the linen as this sharp edge may end up cutting the linen when it is pulled tightly over it.
It is easier to get an even stretch with primed linen than unprimed linen. There is a trick I have heard of, of applying water to the back of a saggy linen canvas, and as the sag reappears after a week you keep this up for a few weeks and eventually, it mostly disappears. I have found that this is true of hot water applied to a dent in the canvas, a pushed up little point in the canvas (cotton or linen), but I have never had it work on shrinking canvas that is sagging. All quality oil-primed linen is sized with synthetic glue (instead of the classic rabbit skin glue which has been found to cause problems over time by absorbing moisture from the air and swelling) so you can use water to help tighten it, if you want to give it a try.
Also, remember with unprimed linen that you don’t want to stretch tight – evenly but not tight – because when you add the sizing or primer the water will cause the canvas to shrink and tighten – if there is too much tension the bars will bow significantly as the linen is pulled too tight.
Stretching unprimed linen takes practice. When stretching linen instead of starting in the centre of each side and creating a diamond shape some artists start by stapling the four corners first, making sure that the bars are following the weave lines, then stretching as you would cotton and when you get to the corners remove the staple there and fold the corners as normal.
Read more in our canvas blog article – Choosing the Right Canvas.
The amount of canvas
Canvas comes in rolls which are 2.10m or 1.83m wide and 10m long. You can purchase the full roll or metres cut off the roll (these must be whole metres, not partial).
The amount of canvas you will need is affected by how thick the bars are and if you are wrapping around the bars to the back. Most artists do a ‘gallery wrap’ these days, wrapping around and stapling on the back, but some still use tacks on the sides. For standard-depth bars add 2-3cm for the bars thickness plus 3-5cm to wrap around to the back and for gripping to pull- this means adding 5-8cm to each side or about 10-15cm to each measurement of the canvas rectangle. So for a 60x60cm standard-depth stretched canvas you would need a 75x75cm piece of canvas. For deep-profile bars add 20cm to each side measurement. So for a 60x60cm deep-edged stretched canvas you would need an 80x80cm piece of canvas. Any extra is useful for having something to grip with the pliers and pull on, the excess can then be trimmed off or for a super strong and neat edge it can be folded under and the second row of staples added to hold the fold down.
Assembling the stretcher frame
Lay out two pairs of stretcher bars – ours are cut with a mitred mortise and tenon joint so no additional fixing is needed. Each corner join will consist of a flat slot end inserting into an angle flap end. All the bars have a cantilever so the canvas is stretched over bars that slant downward towards the centre of the frame so you don’t get an impression from the edge of the bar on the canvas from behind as you paint, the canvas only touches the very outside rim of the stretcher frame. The deep-profile bars have a roll of extra wood to create a rim around the outside of the stretcher frame and the standard depth bars are shaped to slope at an angle. Be sure the flat sides are all facing down so then you will have the angled sides all facing upwards to create the cantilever. Use a rubber mallet to knock them into place. If you only have a hammer you can use it instead but be sure to use a piece of scrap wood between the hammer and the stretcher bar as hammer dents can show as visible dents in the side of your stretched canvas, it pulls so tightly all contours of the wood are followed, especially if the dent is on a part where the canvas touches.
Inspect the outer edges of the frame. On occasion, a very sharp corner may need sanding so that it doesn’t damage the canvas when it’s pulled very tightly over it.
If you’ve hammered all the corners as far as they will go it should be very near square (all the corners at 90 degrees). But you should always check each one. Measure both diagonals and compare the measurements to ensure you have created a perfect rectangle – the two measurements should be very near the same. Tap a bit at the sides of the corners until both diagonals are the same.
Stretching the canvas
- Add 20 to 30cm to your stretcher frame measurements for wrapping around to the back on both sides and cut your piece of canvas from the roll using heavy duty scissors or a knife and straight edge. (20cm for standard-depth, 30cm for deep-profile)
- Lay the canvas piece on a clean floor or table, if it is primed, ensure that the primed side is face down.
- Centre the prepared stretcher frame face down (flat side up) on the canvas piece, checking that the weave of the fabric is parallel to the stretcher bars.
- If it feels like you have bumped the frame out of alignment check the diagonals again and adjust if needed. For big canvases, it is best to build your stretcher frame and then lay it on the canvas piece before doing the final measuring diagonally and knocking it to adjust it to be square. Because if you do it before you lay it down it will move a bit. Knocking with a mallet often takes just one blow on 2 opposing corners (not on the tip of the corner, but on the flat side of a corner, choose the one that needs to be pushed in) to move the measurement a cm or more. So remember that a tap does a lot at this point.
- Stretch and staple – the goal is even tension. Fold one side of the canvas back over the frame. Secure with a staple in the centre of the frame. You will be stretching from the centre and working your way to the corners, always turning the frame or moving yourself around the floor, alternating opposite sides so the tension is even across all parts. After the first staple, you will need to use the canvas pliers to grip the canvas edge (try folding the canvas edge if you need a thicker bit to grip) and rock the pliers to pull the canvas tight. The usual method is to work on the bar nearest you and gripping the canvas edge with the pliers in an underhand grip, rock the pliers away from you to tug the canvas up over the edge until you see all the wrinkles are out of the back of the canvas and you see a sharp edge on the bar. Next put your finger on the canvas to hold it taut, drop the pliers and pick up the staple gun with that hand and add a staple. The canvas doesn’t spring back strongly so your finger is enough. If you don’t have canvas pliers the pulling can be done with your hands, it is just a bit hard on them. The first staple on each side should be taut – if you turn the canvas over you should see a diamond pattern showing the tension.
- Work your way out from the centre, on opposite sides, back and forth until you are almost finished, nearing the corners. Insert the staples 5 to 20 cm apart, I tend to do 10 – 15cm between staples on large canvases and 5- 10cm on smaller ones. (The centre-cross-stretching method is a time-honoured technique but there is also a method for stretching that traces the shape of the stretcher frame on the canvas and working to follow the weave stretches from the corners inward, rather than the centre outward. I have not tried this method but it is supposed to give more even tension.)
- If your canvas is not primed do not pull it very tight as the priming will wet the canvas which causes it to shrink and the tension will either pull out the staples or bend the wood.
- If they are sticking up at all you may wish to tap the staples in further with a tack hammer. I go around the whole canvas when it is finished and tap all the staples. You can’t always see when they are not fully in.
- Stop stapling at least 10cm from the corner to give yourself room to manipulate the fabric for the corner fold.
- Note that unprimed linen can be a bit fiddly to stretch until you have had practice. It can be stretchy and you may need to add some temporary staples in the corners at the beginning to keep the weave lined up and then remove them after you have progressed out from the centre.
Folding the corners
The goal of folding a neat corner in the back is to create the flattest, smoothest lump on the back and to control the location of the small fold bump on the side. Because the small fold bump shows slightly on the edge, if you wish to you can ensure that it is on the top and bottom so that the sides are an unbroken line. So if you know what orientation you will be using for the stretched canvas, you can choose which way to pull over the fold.
1. On the bars that will be the side of the canvas (not the top or bottom) continue stretching and stapling all the way to the corner with a final staple parallel to the top edge near the edge of the fabric, making your priority the smooth taut edge of the canvas on the side bar. To keep track of which way you are folding the canvas I find it helpful to do step one on all four corners before you go back to finish the folds.
2. Still making the appearance of the visible side and corner the priority, pull the flap toward the centre of the canvas and create a triangular fold that falls just where a mitre join would in the corner of the wood frame – double check that the corner is smooth and not puckered. Press the fold with your fingers.
3. The final fold usually involves a bit of wiggling, reaching under the fold and making sure all is tucked in smoothly and the corner is not loose or puckered – pull the last flap over so that the side is parallel to the top bar, but not showing over the edge. Staple down the fold taking care not to staple across the corner join in the stretcher frame. Stapling over the join in the frame would mean that you couldn’t use the wedges to expand the corners later.
Assess the results
Inspect your stretched canvas. It should not have wavy lines in the weave or have wrinkles or sags. You should not be able to easily push it from the front to touch the cross bars. If it looks as if a part is under more tension or less tension than you’d like simply remove a few staples to loosen an area or get a grip with your pliers to tighten it, and then restaple the area. The staple lifter is helpful here.
- Turn the canvas over and see if you have any slack areas and remove staples and re-stretch them until it is all evenly taut.
- You may wish to trim any excess canvas or fold the extra fabric under and staple again, but some artists just leave it because generous canvas margins provide work edges for when the canvas needs re-stretching or conservation in the future. Never cut away fabric at the corners. For a very neat reverse side, you can tuck under the extra fabric and make a second row of staples to hold it in place.
- Tap in corner wedges to expand the corners to complete the tension.
- Tap in centre bar wedges if needed.
- Using a spray bottle, mist the back of the canvas with water for a bit more tightening, if needed
There are really only a few things that can go wrong when stretching a canvas and they can all be solved by re-stretching the canvas.
- Loose or sagging canvas (not tight enough stretching of the canvas)
- Wavy areas of canvas (uneven tension of the canvas)
- Warping of the stretcher bars, so that the whole canvas doesn’t lay flat against the wall (uneven tension or bars not strong enough for the amount of tension)
- Bending of the crossbars so they are not flat against the wall, but curve to protrude out of the back (too tight tension, usually from overstretching unprimed canvas that then shrinks when it is primed).
Stretching your own canvas gives you control over all the aspects of your painting surface including the overall size; the depth; the absorbency, the colour and texture of the primer; the texture/grain and weight of the canvas and more. When you know the particular qualities you want for your painting surface, stretching your own means you don’t have to settle for a canvas that isn’t quite right, you can meet your exact specifications. The finished product is also of a superior quality, with heavier bars and better canvas than most ready-made canvases. The process is not difficult and is quite straightforward – it takes longer to explain it than to do it!
When preparing surfaces in the studio it is often most efficient to do a batch, unless you are preparing one very large support. The size of the batch will be determined by both the space available – perhaps to lay out canvases while primer is drying – and how many steps you can do in the allotted time you have – perhaps you will build six stretcher frames and cut out the canvas one day and stretch the six canvases the next day and over another day or two prime and sand them. Using primed canvas saves a lot of work and you don’t need as much space for drying but you may not get the precise surface you wish. Of course, you can always use primed canvas and add a topcoat of your preferred ground. This could even be an absorbent watercolour ground, if you wish to paint with watercolour on canvas rather than paper.
Priming the canvas
If you have used primed canvas you can begin painting straight away or you can add additional priming to the surface to give a particular surface quality to your canvas such as an oil primer, an absorbent ground, a rough surface such as a pastel ground, a few more coats of acrylic primer so that it is whiter, a non-absorbent primer so the surface is slicker, as well as other primers. If you have stretched un-primed canvas you can start painting straight away in acrylic but the surface will repel water somewhat and if you intend to stain the bare canvas you will probably wish to add a flow release agent (diluted according to the instructions on the package).
If you wish to paint with oil on bare canvas be aware that it will not last forever as drying oils (all oils used to make oil paint) will slowly eat the fabric. You will also get a ring of brown oil in a halo around the colour which some artists find unsightly. This leeching of the oil out of the paint also means there is less binder in the colour and it may look chalky and even crumble off. For a sound structure for oil paint, it is recommended to seal the canvas from the paint. This means a size (traditionally rabbit skin glue) and a ground (traditionally chalk gesso). The modern alternative is acrylic primer/gesso that acts as both a size and ground. Apply many thin layers until you can no longer see light through the weave if you hold the canvas up to the light. Your first layers should be thinned with water and scrubbed into the weave in circular motions. Each successive layer should be applied lightly to prevent cracking and to reduce brush marks – add less water to each layer and use as little primer as possible to cover the whole surface, make it a light coat like you are dry-brush painting. Each successive layer should be applied in the opposite direction to the last. Let it become touch-dry between coats, some artists sand each coat if they want a smooth surface. Each brand of primer has a different ratio of acrylic binder, chalk and white pigment – so some are more absorbent and some are more opaque – try a few until you find the one that suits your way of painting.
As an extra step in special circumstances (for acrylic painting that uses transparent layers with almost no colour and lots of water which could draw some small amount of colour from the wood bars or canvas) you may want to apply one coat of gloss acrylic medium before you apply the primer to seal the canvas from any amount of surface-induced discolouration (SID), which might show discolouration in paint which has little pigment in it.
Read more about priming in our blog article – Don’t Be a Square – Preparing Circular Painting Panels.
A canvas just as you wanted it
Now that you have made the perfect canvas you may wish to write on the back along the staples, with a pencil or Sharpie marker, which canvas and primer it is so that when you realise you loved painting on this surface you will know what you used so you can make it again!
The process is not complicated, it is just a few steps and once you know the principles it is quite straightforward. If you are not sure if it is something you want to try, just remember that the worst result is a loose canvas which is not the end of the world. You can always remove some staples and correct it and you should get good at stretching quickly.
Canvas on a Panel
If you like painting on canvas but do not like the bounce you get with a stretched canvas, you can attach your favourite primed or un-primed canvas to a wooden panel to paint on a rigid surface that still has the texture of canvas. The Jackson’s Smooth Plywood Panels are great for this.
Read more in our canvas blog article – Making a Canvas Painting Panel.
Artist Canvas at Jackson’s Art
- Canvas by the metre
- Stretched canvas
- Canvas panels
- Stretcher bars
- Bespoke Canvas Department
- The Canvas Department
Postage on orders shipped standard to mainland UK addresses is free for orders of £39.
Footnote from second paragraph: *Golden Ratio
The proportions of the Golden Ratio (also called Golden Section or Golden Rectangle) create a shape that is considered most aesthetically pleasing throughout western art history. The long sides of the rectangle are 1.618 of the short sides.