I’m a professional artist, and I often get asked how I do stuff. This post is one of a series I intend to put up, in which I thought I would share some working techniques. I do not claim to be an expert in most things I do, and I am generally self-taught, but I have been doing what I do for some years and I’m happy to share my experience with any who are interested.
In this post I will to show you how to stretch paper… properly. And how you can sometimes rescue it if it goes wrong. There is A LOT of detail in this explanation, but don’t be put off – it’s really quite simple, but it seems to be something that people have a lot of trouble with, so I thought I would put in all the detail because I think it sometimes comes down to exactly how you treat the materials. I have been stretching paper for years, and sometimes it does go wrong. You just have to shrug and do it again!
You may have a different method to this, in which case I’d love it if you’d leave a comment about it. What I mean by stretching watercolour paper ‘properly’ is not that this is the only method, but that it’s lovely to paint on properly stretched paper, and not stretching it properly is kind of a waste of your time…
When you paint on paper with water-based paints the paper expands as it gets wet and will not stay flat – in other words it will ‘cockle’. And when it dries, it will not dry nice and flat. The way to keep it flat is to soak it in water before you start, and tape out the paper onto a board while it is still wet. As the paper dries it is prevented from shrinking by the tape, and so it dries under tension. In other words, it is stretched.
While the paper is stretched, you can paint on it and it should remain flat because the tension is sufficiently great that even though the paper may expand, it will not cockle but will be held flat. Occasionally if you get it really very wet it may cockle a little bit, but as it dries it will be pulled back into shape and will dry nice and flat again. Note that as soon as you take the paper off the board it is no-longer under tension, so it is best to make sure you have finished painting before you do this.
What You’ll Need:
1. Paper: generally the most suitable paper is Watercolour Paper. For the best archival properties, and the ability to withstand a certain amount of abuse even when wet, good watercolour paper is made of cotton, not wood, because cotton has longer fibres, which gives it strength, and it does not yellow with age. It is possible to stretch other papers with care, though if the paper is not strong enough it can tear as it dries under tension. I use Hot Pressed watercolour paper with a weight of 300gsm / 140lb, which is thick, but, as watercolour paper goes, only average thickness. Thicker paper is more difficult to stretch and some people claim it is not necessary, but the real reason I use that weight of paper is that hot pressed (smooth surfaced) paper is not generally available in a heavier weight than that.
2. A board to stretch it on: opinions differ on this one. I use 6mm – 12mm thick sheets of MDF (medium desnity fibreboard), with a couple of thin coats of polyurethane varnish to seal the surface. Probably acrylic varnish would also do the job, though I’ve not tried this. After varnishing with either sort, it is helpful to go over the surface of the board lightly with some coarse sandpaper, especially round the edges where your tape will be, to roughen it up a little and help the tape to stick.
You can get away with unvarnished MDF for a while, and the tape will stick all the better to it, but in the end the surface of the board breaks down and eventually the tape will not stick to it at all. I also have some melamine-faced panels of fibreboard from old kitchen units. These also work, but it’s even more important to go over the surface with a bit of coarse sandpaper first to roughen up the surface.
For small pieces, I have also used an old wooden bread board to quite good effect. MDF has no grain and therefore tends to stay flat. Small boards of wood may also stay flat, but plywood has a tendency to warp. Hardboard or masonite might work, though I have not tried this, I imagine it is not rigid enough if you want a large board but might be ok for a small board. I also imagine the same would apply as regards varnishing – the surface will not last long if you don’t varnish it.
3. Brown gummed paper tape: this comes in different widths. It’s more difficult to use the thinner stuff and generally I’d stick to the two-inch wide, or wider stuff, unless you’re stretching really little pieces of paper.
4. A roll of kitchen towel: for drying the paper. Make sure it is clean, and that it hasn’t picked up any grease or anything else!
5. A bowl of clean water: to wet the gummed tape.
How to stretch the paper:
1. Mark the side of the paper that you want to paint on. Watercolour paper is generally slightly different on one side to another and, if you prefer to paint on a certain side, it’s a good idea to mark in the corner of the side you want to use. if you don’t care, it doesn’t matter!
2. Don’t try to stick paper to a board already covered in old bits of tape. If you have a single layer of old tape, I find it enough to wet it at this point before putting the paper into soak, and I’m able to pick off the old bits of tape before the paper is finished soaking. If you have heaps of old tape stuck to your board you might want to make sure you get that off before you start.
3. Soak the paper in clean, cold water. I don’t time how long I soak paper for, but it should probably be 5 minutes at least, and not longer than about 20. Soaking for too long risks washing all the sizing out of the paper, making it too absorbent for painting.
I soak mine in the bath, because I don’t have anything bigger. You can soak it in the sink if that’s big enough, or anything else handy. When I lived where I didn’t have a bath, and I wanted to soak large bits of paper I put it against the tiled wall of the shower and sprayed it with the shower attachment for a few minutes, both sides. The wet sticks the paper to the tiles, so you don’t have to hold it up by hand. It’s a little tedious, but it works.
Whatever you do, make sure the container (or your shower wall) is clean. You don’t want any traces of grease or soap to be picked up, especially if you are going to be using watercolour or gouache.
4. Meanwhile you can pick off the old tape from your board as mentioned in number 2: soak any old bits of tape and pick them off – they aren’t helpful!
5. Pick up your soaked paper, let it drain and lay it on the board, with the side up that you want to use.
6. Dry your hands, because if you get the roll of gummed tape wet, it will be ruined!
7. Tear off lengths of gummed tape, one length for each side of the paper. Then put the rest of the roll of tape away from the water. Meanwhile the wet paper will have had a couple of minutes to settle, which seems to help.
8. Wet a piece of gummed tape. I do this by holding one end of a piece of gummed tape, quickly drawing it through the water and getting rid of excess water by holding it up and running it between two fingers. Run your fingers down the tape once just once, to get the surplus water off. You could probably wet it with a piece of sponge, but that would require finding a piece of sponge, and also finding a clean surface to lay the tape on. However you do it, you want the tape completely wetted on the gummed side, but not soaked for any length of time so that the gum washes off.
9. Stick down one edge of your paper carefully and neatly! This may sound obvious, but stretching paper is a tricky thing and getting it neat and even will minimize the risk of the paper coming off as it dries. Do make sure that the tape is stuck down all the way along, and that it doesn’t have wrinkled bits, or dry bits, or air bubbles. Also don’t have bits of tape sticking over beyond the edge of the board as I suspect this will also encourage it to start to peel off.
10. Stick down the other sides.
11. Mop up surface water from the paper and tape: I find it’s best to lay a single layer of kitchen towel over all the surface of the paper to suck up surface water, then use that same handfull of towel to go around the tape on the edges. Doing it this way round means you also do not risk getting gum from the tape on the rest of your paper.
12. Stand the board up to dry, and rotate it a couple of times when it first starts to dry: This is another point where opinions differ. My mother (who also paints) was always told that you should lay the board flat to dry. I find that if you do that then excess water will ooze out around the edge of the paper and the tape will stay quite wet around the edge for a long time. The trick is to get the tape round the edge to dry quickly, so that it is already holding the paper tightly before the paper dries out completely, shrinks, and begins to pull on the tape. So what I do is I stand the board on edge. Excess water will drain to the bottom edge, but I rotate it a few times so there is not a reservoir of wet at the bottom. How frequently I turn it and how often depends on where the board is. Outside on a warm day I might turn it every five minutes a couple of times, drying slowly inside I might turn it every twenty minutes or so.
13. Drying outside is best if possible: If it is not damp outside, or very very cold, I always stand the board up outside to dry. There will be a better air-flow round the paper and it might even be warm and breezy, in which case your paper might be bone dry in an hour. If you stand it up inside, it can be damp for four or five hours. If it is sunny I recommend facing the paper away from the sun, but warm sun on the back of the board seems to be ok. I also recommend leaning the board against something, with the paper facing inwards, so that it is protected against bits of dust, insects, blowing over and falling face-down, and in my case, any action by overly helpful cats.
Preventing problems and rescuing failures
Stretching paper can be tricky, and sometimes there are failures, and sometimes spotting a failure just in time is enough to rescue the situation. Periodically inspecting the tape as the paper dries helps: have a look round the edges and see if it is coming away anywhere and if it is, take swift action!
1. If the tape is coming unstuck from the paper at one point: If the paper is not totally dry it will probably be enough to add a piece of tape, sticking it over the existing tape for longer than the length that has failed, and covering a little more of the paper (see opposite). Don’t get the new piece of tape too wet as you want it to dry quickly.
2. If the paper has come unstuck along an entire side. If the other edges are sound and well stuck, you can try this: Pull off the failed bit of tape, then get a large, soft, clean paintbrush and paint water over the entire surface of the paper except for the stuck edges – don’t get those wet again. Also be careful not to brush gum left along the failed edge onto the clean painting-surface of your paper. After you have soaked the surface of the paper like this for a few minutes you can stick down the failed edge with more tape. There may be a small bump as the edge will have expanded, but if you can get the failed edge stuck down soundly, it should smooth out when it dries.
Both of these methods above might result in a the paper going a little slack and cockling when you paint with it if you get it very wet, but there should be enough tension to pull it nice and flat when it dries out again.
3. If the paper has come away on more than one edge: Pull it off, soak it and start again! When you soak it you can carefully remove any bits of tape, but try not to soak it for too long this time: soaking removes some of the sizing each time which will mean when you come to paint on the paper you might find it a lot more absorbent than you want it to be. If it fails a second time, I’d recommend starting again with a new piece of paper, and using the old piece for something that you aren’t going to put a lot of time and work into.
4. If the tape comes away from the board: If your tape is not gripping the board, you need to do something with the board. Unless this is in a very small area, in which case you might be able to stick it down, it’s probably best to start again anyway. In which case, if your board is smooth and varnished, or some other shiny surface, try going over the surface of the board with coarse sandpaper, especially near the edges, to take off some of the surface and give the tape something to grip. You shouldn’t have to sandpaper it heavily, but do wipe off the sanded surface afterwards with a damp cloth, because the dust won’t help.
If you’ve used something like unvarnished mdf or wood the tape may be coming off because the surface is breaking down. In which case putting on a coat of varnish may help, or just getting a new board with a better surface.
Don’t be put off. It is a joy to paint on properly stretched paper that doesn’t move about when you get it wet! This is a lot of detail and in fact the process is basically very simple. I’m only adding in all these details because I know some people seem to have trouble…
Happy stretching 🙂