Warped canvas board

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Emibub

Emibub

PFG, Picture Framing God
Joined
Nov 2, 2001
Posts
9,246
Loc
Centennial, CO, USA
I had a framed painting on canvas board come in this week that has warped. It has been framed since 1979. It has warped so badly that you can see both edges along the top and bottom. I have flattened it a bit with weights and have reassembled it and have added foamcore to the back(it had cardboard before). I feel it is a temporary solution as I think the will of the canvas board is going to win out over the foamcore in time.

The client says it hasn't been exposed to any extraordinary humidity. Any ideas on how to flatten canvas board?
 
Hello again Kathy,

Was it glazed? It wouldn't necessairily be humidity that did it - could have been dryness as well. Depending on whether it's convex or concave, something shrunk, and pulled the back with it, or something expanded and pushed the back into itself - or vicea versa. Hugh wrote a nice article in the PFM about warping due to different treatments of front and back, and this sounds like it falls into that catagory.

I don't think that there is anything that can be done at the framing end of things. Gradual and plentiful humidification, and then pressing dry between blotters and weights might work, but that's more of a conservation treatment than a framing one. And after treatment, it would need to go into a sealed frame to prevent a recurrance, especially if it's going back into the same environment.

Rebecca
 
Rebecca, You are so helpful. It is definitely concave. It has also shrunk. The canvas board says "24x30", but at this point it measures 23-5/8x30. So, it has only shrunk one way. I have no idea what it is coated with. Again I don't think the client is expecting miracles. In fact I told her if I can't flatten it she might have to consider having the frame altered or start with a new one. I'm assuming she will just take it as is since I have it in the frame again, but I am going to caution her that it is a temporary fix. She paid some bucks for the art. It had a price of $1,000 on the back of it.
 
A slight Frankenthread, here, Rebecca. When I first started framing, 20 some odd years ago, the practice was to never put dust covers on oil paintings. Now, I'm reading put covers on oil paintings. Or, more recently, put covers on, but punch holes in them. What's body to do? What's the current recommendation among conservators? Inquiring minds want to know??? :confused:
 
My conservator says putting on a dust cover and poping holes creates an inviting atmosphere for bugs or mold. "If you go to the trouble of putting it on then leave it intact." He tells me.

When liners and fillets push the canvas beyond the back fo the frame I like to paper the back. For years I cut out the center section exposing the canvas to let it breathe. Oh well. It still looks better than seeing all the off sets etc.
 
Kathy, can you add a fillet to the existing frame to cover the space left when the board shrunk away from it? More of a bandaid than a cure but it might be enough to make the customer happy.

Kit
 
Dear Kathy,
Here in Texas I have seen lots of warped boards. These are a cheap alternative to stretched canvas, intended for student use, or for studies. They have a rough surface and tear up good brushes, so most professional artists don't like them. I have not had very good luck getting these to flatten out for any lenght of time, either. In the past, I have had mixed success with doing what Rebecca said about humidity and pressing. However, the ones I have tried were mainly children's art, not worth $1000! What about putting something stiffer than foamboard, like maybe gaterfoam, behind it?
By the way, just out of curiousity, I wonder if a conservator could peel the cardboard off the back, and line it like a regular canvas, and stretch it? Most of the ones I've seen are not worth this extreme, I'm just wondering out loud if this is possible.

Leslie
 
correct me if I am wrong..but this is a canvas panel type board?..where a piece of canvas is glued to a piece of "chipboard"?....well this isn't a archival method of correcting it ...but if you were to adhere (glue) a piece of canvas or heavy paper to the back of the board and then place it in a press or heavy weights you may be able to unwarp the board.....You might want to discuss this option with your customer as a possible alternative..seeing the painting was done on a "non-archival" material in the 1st place
 
Kathy,
Is this a canvas mounted to 1/8" paper mount board? A conservator may be your only good answer. If it really has shrunk that much I would be cautious that the pigments haven't dried to the point that they crack when flattening is attempted.

Rebecca,
Could the canvas be removed from the board backing and lined & stretched in a more traditional manor? It would not then need glazing and a sealed frame. Before I knew better, I peeeled one of these off of a badly water-damaged mount, cleaned as much of the old board from the back of the canvas as I could, and remounted to 8-ply rag board using PVA glue. Not recommended, but is there an equivalent treatment that meets conservation standards?
 
Wally,
Since it has only "shrunk" in one direction, I wonder if it was just maufactured short to begin with. I have seen plenty of these boards not the real size, right out of the package.
 
Canvasette type panels illustrate the folly of
mounting art on paper boards;(This problem is also
true for photos mounted on mat board)if the board
warps, we are in big trouble. It is not surprising
that the board shrank in one direction, i.e. perpendicular to the grain. The poor quality of
the cloth and the scant amount that is on the
back of the board makes it unlikely that it could
be stretched successfully. Can it be installed in
a new, smaller frame with spacers tailored to fit
its concave shape? Its concacity may not be that
evident if its edges are covered.
Solid backing boards that are screwed to the
stretcher bars of a canvas will provide two
critical forms of protection. They will aid in
averting punctures of the canvas from the back
and they will keep the canvas from vibrating
when it is transported. They will not trap any
air or humidity, but will do something to discourage the entry of pollution that may come
at the canvas from the back side.

Hugh
 
Wally -

If one did want to flatten one of these, and the humidification thing didn't work, I would be tempted to try your removal and remount system, but without the PVA. I'd be more inclined to put Japanese paper strips at the edges of the canvas support and wrap these around to the back of a new rigid backing (probably matboard and Corolast). I do this a occasionally with badly water damaged illustration boards.

Rebecca
 
Well, at least I am now armed with enough information to tell my client. It is one of those 1/8" canvas boards. I did check to make sure the canvas hadn't lifted up before I attempted to flatten it with weight. I thought of countermounting it on the back but I don't want to involve heat. I hadn't thought of a fillet. That at least is an alternative if she doesn't want to pay for a whole new frame.

It is funny, as long as I've been framing I haven't dealt with this type of stuff much. When you are running somebody else's store it is very easy to send people away or to say you can't fix something. Now that it is my store I don't want to send anybody away so I am more willing to at least look at this stuff. I had better start looking for a local conservator here in Denver so I can start passing this stuff off. Thanks for all the help everybody.
 
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