It certainly does look like something has been run over the back of the painting, but central heating has a terrible effect on furniture so it’s feasible that it may have caused this too. Perhaps the fault lies with the canvas rather than the paint – maybe the cloth has got overly dry and warped?

Gail

I was going to suggest what Marty said. Take a water spritzer and spray the back of the canvas. As it dries, it might just pull it back to normal. The lines remind me a little of when old leather furniture gets too dry. I wonder what the back of the canvas looks like?

I’m not convinced anything was leaning against the canvas, because there are so many of the marks.

Good luck, I hope you figure it out!!!

It would seem it was leant against something (even though they say it was not, in renovations and moves all sorts of stuff gets put where it should not and anything can happen).

That’s exactly what it looks like to me too – creasing from an edge pressing in from the back (one of the good reasons to close off the back of framed works).

One suggestion is too dampen the back of the canvas and let it tighten. This often pulls out any dints and marks in the canvas.

Acrylic is a flexible paint when dry, unlike oils, and should not crack.

Just wanted to add this in case it’s ever an issue with someone – acrylic paint can get much more rigid when cold so be careful, rolling or bending a painting that would normally pose no risk can then cause cracking.

Einion

Karen, I tend to agree with LightDancer’s reply about this looking like leather furniture that has gotten too dry.

Was the painting done in a humid environment? If the canvas fibers had been in a moist environment for a long time before the painting was done, then the completed painting was shipped to England where it was hanging in a very dry, centrally heated environment, I wonder if the canvas didn’t dry out and shrink so much that it pulled the dried acrylic paint and layers of Cryla varnish so tightly together that they began to buckle up into these ridges. I think the dried paint may be just too “crowded” on a canvas support that has shrunken dramatically beneath it.

The canvas fibers may swell and stretch if they are remoistened from the back, thus relaxing and letting the paint layer smooth out again, but to what end? Unless some way can be found to keep the canvas support from becoming overly dry and tight in that central heating, this process may just happen again. And what if moistening the canvas this way causes too much stretching too suddenly? Could the paint layer be harmed even more?

These ridges or cracks may disappear on their own once spring and summer in England provide a naturally higher humidity level and less stressful environment for this painting to hang in. Many of us who have central heating suffer from excessively dry air in our homes during the cold fall and winter months. We keep a humidifier going in our home to help relieve the dry air this time of year. Perhaps your client might want to run a humidifier in the room where the painting hangs to very gradually reintroduce some moisture into the environment around the painting. I think gradual is better than a sudden change from a misting. I know acrylic paints are wonderfully tough and durable, but I wouldn’t want to take a chance of damaging your lovely painting.

Perhaps the best thing to do is to seek the advice of a professional art restorer.

Beverly

…

Beverly, I think your theory about the humidity level difference is probably bang-on as it was painted in a fairly humid environment and now perhaps that it has been exposed to very warm, dry conditions the result is this shrinking.

I will suggest the humidifier and hope that she won’t curse me too much for more inconvenience!

I was wondering if framing the painting behind glass might not protect it as well from these varying environmental conditions?

I think the problem is that there has been so much humidity lost through the unprotected back of the canvas. Framing it under glass might help if the framer also does something to seal off and protect the back of the painting, which I think they would.

I know we’ve had discussions on this forum about the merits or potential problems of presealing the back of the stretched canvas before beginning the painting on the front. When I paint on stretched canvas, whether with oils or acrylics, I like to first give the back of the canvas a couple of coats of matte acrylic medium diluted with water so it is easily spreadable. I use a fairly stiff brush so I can work the medium into the canvas and let each coat dry thoroughly before applying the next coat. I then allow this canvas to dry for two or three days before I begin working on the other side. If I’m going to use oil paints, I prepare the painting side with two or three coats of gesso and allow enough drying time before beginning the actual painting.

The oil paintings and acrylic paintings that I have done this way are in excellent condition with no apparent effects from changes in humidity through the seasons. I live in Pennsylvania in the USA so we get the full gamut of seasons from hot, humid summers to frigid winters.

I don’t suggest this as a solution to the current problem affecting this portrait, however, since this method is to be applied before the painting is done. I can tell you that I notice that the cotton canvas appears to swell and sag a bit when the first coat of acrylic medium and water is applied to the back. But it dries tight as a drum and the second coat doesn’t cause any further sagging. But it is evidence that the canvas fibers will really swell dramatically when they absorb some water.

A friend of mine bought a very expensive giclee print on stretched canvas done by a well-known American artist. It is quite a large print and there is no extra support of any kind on the back of the canvas stretcher frame. There is also no sort of protective backing to seal off the unprimed canvas back of this print. She hates air conditioning so her home gets quite humid during the warm months. During the humid spring and summer months she notices that the canvas has a visible sag because the canvas fibers have absorbed a lot of extra humidity and swollen accordingly. During the colder months when her furnace is heating the house, the air dries out and this canvas seems to tighten back to the original state. The dramatic changes in humidity from central heating in fall and winter to high humidity in spring and summer are having a dramatic effect on this print, however.

Considering the large sum of money she paid for this print on canvas, she is understandably upset. The gallery who sold her the print has no idea how to prevent this since the inks used to do the print are water based and then given a protective seal on the front side only. They have offered to refund her money or exchange this print for another of her choice. But this is one of those personalized giclees with a bit of hand-painted touches of paints applied by “artists trained by the master himself” — a real money grabbing scheme, in my opinion. For that reason, my friend doesn’t want to give up this particular print. So, she’s stuck with the seasonal expansion and shrinkage of this large canvas print. Who knows what long term effects this will have.

I only mention this story because your client’s problem with the acrylic portrait brought to mind what extremes in humidity levels might do to stretched canvas.

I wish all the best in getting this problem resolved.

Beverly

Thanks so much Beverley for your interesting comments and advice. The region of South Africa that I live in has a very temperate climate so I have never experienced this problem first hand before.

In the future I will coat the back of the canvases with Acrylic medium first before priming the painting side. This would seem to be an excellent practice and I wish I had heard about it before! Hopefully this will prevent this happening again.

I will encourage her to think about having the painting framed – though I know framing in the UK is rather expensive.

Other than that all I can think of is offering to try and paint her another one, but it did take an awfully long time – *sigh*..

You are certainly welcome. I hope it sheds a bit of light on this problem. You will probably find there are plenty of others on this forum who disagree with the practice of sealing the back of the canvas, especially if you are going to do an oil painting. I don’t think there will be any ill effects if you are doing an acrylic painting on the front side of the canvas. But I like to do this for my oil paintings, as well. I can only go by my own personal experiences using this practice. Since my paintings are not done in an extreme environment to begin with (we do like air conditioning in the summer, hence we have pretty stable humidity levels), I don’t feel that I’m sealing in any excessive amount of moisture in the raw canvas before I begin the painting.

I sort of have a test case going, you might say. I did an oil portrait for the lady with the sagging giclee print. The portrait was of her two children and I did it about three years ago. It is hanging in the same environment as the expensive giclee print on canvas. Although the portrait canvas is not quite as large as the giclee print canvas, my oil painting is doing just fine. I visit this lady on a fairly regular basis so I get a chance to check up on the painting I did for her. It shows no ill effects and is still drum tight as the day I finished it. I wonder if it would be suffering the same problems as her giclee print if I had not sealed the back of the canvas.

Others swear an oil painting on canvas must be able to “breathe” and it would be a mistake to seal the back of the canvas. This may be true. You’ll have to follow your own instincts on this matter.

By the way, I visited your web site and your work is just wonderful.

All the best,

Beverly

…

By the way – when shipping my paintings overseas, I have always rolled them (very carefully of course, with layers of bubble-wrap over a solid tube, then placed inside a larger tube for protection) and I know for a fact that all of the oil paintings are still perfect after several years . Would you have any idea if rolling the paintings after they have been sealed at the back would be detrimental?

I don’t think so. The idea of using the acrylic medium (slightly diluted with water) to seal the back of the canvas came from a book I have by an artist who paints in both acrylics and oils. The two layers of acrylic medium are intended to help stabilize and protect the otherwise untreated back of the canvas fibers. It by no means makes them stiff and rigid, nor does it make the back of the canvas absolutely air tight. It helps to keep moisture and pollutants from entering the canvas fibers or from penetrating through the weave, but the canvas remains at least as flexible as, say, the painted side of an acrylic painting. If your oil paintings can be rolled and suffer no ill effects, then I don’t see any reason that sealing the backs of the canvas should make a difference that way.

I admit I was nervous about the oil portrait I did for my friend hanging in her home when I realized how high the humidity levels got in the spring and summer. After seeing what was going on with the giclee print on canvas that she has, I’m glad I did seal the back of my canvas before I began the painting. So far, so good. I did explain to her how such varying temperature and humidity levels can be harmful to art work and that it’s best to keep the climate conditions as even as possible, but to no avail. She loves hot, sticky summer weather and keeps her house open to the “fresh summer air”. Oh, well…

If you are going to try sealing the backs of your canvases, as I do, perhaps try it on a limited basis first until you get an idea of how well it will work for you. If you can spare a stretched canvas to experiment with, try sealing the back and letting it dry thoroughly. I don’t put on a really thick coat of the acrylic medium on the back. Just two light coats brushed well into the weave of the canvas. Then gesso or paint the front just to get the effect. Once this has all dried, take the canvas off the stretchers and roll it up as you would for shipment. Leave it rolled for as long as a shipment usually takes to arrive at a destination. Unroll it and check it closely to see if you notice any bad effects. Once you are comfortable with it, then you can adopt it as a regular practice.

By the way, was the acrylic portrait mentioned in the beginning of this thread shipped rolled, as well? Do you know if your client in England had the canvas re-stretched on stretcher bars before hanging it? I’m wondering if it was not stretched tightly enough and if that contributed to the canvas shrinking up so dramatically when placed in very dry centrally heated rooms. Perhaps this wouldn’t happen if the painting had been shipped on its original stretcher. I know it’s a lot bulkier and probably more expensive to ship that way. But how can you, the artist, be sure your work will be properly handled at the final destination? Just some details worth thinking about.

Best of luck and happy painting!

Beverly