Opinions Wanted Curious about the backing coming from my canvas conservators

[The Village Framer]

I saw cup washers mentioned in another thread and it reminded me that my two canvas conservators both attach a piece of regular foam core to the back of their repaired canvases (with cup washers). They both do outstanding work, and the back looks very clean but I question the regular foam core, I normally back canvas with Coroplast and I know my paper conservator frowns on all kinds of foam core. I considered changing out the regular foam core backs on these canvases, but there's a sticker with all of the conservator's info (name, phone, conservation procedures) which I feel I should leave with the piece. So, what do you guys think? Not much to worry about? Call the conservators and ask that they back with Coroplast? (which to me feels awfully presumptuous/snotty; I'm not a conservator after all).

While we're at it; screwing the foam to the back of the painting obviously puts holes in the stretcher bars. If it's an old and original stretcher/painting is that an issue?

 

[wpfay]

I don't think the nature of the backing on an oil painting us as important as its presence in protecting the canvas from damage from behind. Since the foamboard isn't contained, and the edges where any outgassing would occur are open to the environment I don't think that using regular foamboard or generic polyflute as a backing panel would impose any risk to the canvas. My only concern would be ambient humidity and the fact that foamboard reacts to it (as does mat board) whereas polyflute does not. The only drawback to polyflute are the open flute cells which can (possibly should) be taped off. Coroplast has a new polypropylene panel on the market called Stinger Board ( http://stinger.coroplast.com/ ) that has a honeycomb core making it much more rigid and closes the cells.

 

[Shayla]

If you back something with polyflute, do you only use one piece, or do you
use two, with the corrugated pattern running crosswise piece to piece?
If you use two, on this or any job, do you attach them?

 

[The Village Framer]

If you back something with polyflute, do you only use one piece, or do you
use two, with the corrugated pattern running crosswise piece to piece?
If you use two, on this or any job, do you attach them?

I generally just use one piece unless the piece is very large, I'm really using it more for puncture protection than stability issues and I feel like one piece of coroplast is enough.

 

[Dave]

One is all that is necessary for a framed canvas.

When cross graining polyflute, I roll on Frank's Fabric adhesive and weight.

 

[Gilder]

I would send it back and request acid free board instead, just to have a piece of mind.
Probably even ask why he/she put the regular board there. What's the reason?

 

[DesignsInk]

I would send it back and request acid free board instead, just to have a piece of mind. Probably even ask why he/she put the regular board there. What's the reason?

Many conservators consider clay coating a much better barrier than a thin sheet of buffered paper. And as far as the whole "out-gassing" issue, back in 2008, International Standards Organization released their updated document "ISO18902 - Imaging Materials - Processes imaging materials - Albums, framing and storage materials" which approves the use of foam center boards in enclosed packages including picture frames. In the decades that foam boards have been around there has been no proof--from any source, conservators, museums, framers--proving that foam center boards were the reason for any image damage. There is no proof. Just saying, as an FYI.
Chris Paschke

 

[Gilder]

Many conservators consider clay coating a much better barrier than a thin sheet of buffered paper. And as far as the whole "out-gassing" issue, back in 2008, International Standards Organization released their updated document "ISO18902 - Imaging Materials - Processes imaging materials - Albums, framing and storage materials" which approves the use of foam center boards in enclosed packages including picture frames. In the decades that foam boards have been around there has been no proof--from any source, conservators, museums, framers--proving that foam center boards were the reason for any image damage. There is no proof. Just saying, as an FYI.
Chris Paschke

That could be very well true, great news. My point is: I don't have time to think about it, busy with everything else and acid free board is what, maybe a dollar more. Just put acid free board and everybody is happy, considering on canvas no backing paper and board will be visible, some customers understand the difference between regular and acid free.

 

[The Village Framer]

Any thoughts on putting holes in original (old) stretcher bars? Normally I wouldn't think twice but on a valuable piece is the stretcher considered part of the artwork and therefore shouldn't be altered irreversibly?

 

[Gilder]

Any thoughts on putting holes in original (old) stretcher bars? Normally I wouldn't think twice but on a valuable piece is the stretcher considered part of the artwork and therefore shouldn't be altered irreversibly?

My understanding is that stretcher is just a stretcher. I would not deliberately destroy it but it suppose to do the job, nothing else.