Acidity barrier

[Coxby]

A client brought in a watercolour with a mount which was positive when tested for acidity. She wants to keep the mount which is decorated with various lines and a wash. I offered to imitate the wash and lines on a new Cotton Core or Artique mount but to keep costs down I wondered if by placing a piece of 550 micron barrier board behind the mount and cutting the aperture to the exact size of the old mount, in the spirit of conservation, would this suffice?

I am aware that this would not do for top level museum standards, but the client is happy to drop down to conservation level and use Arqadia's Artique. Would 550 micron suffice or would we have to go for a thicker, and ungainly, board? Your help would be appreciated.

[JFeig]

The answer is no.

The contanimation will pass right through the bottom mount.

To be realistic, a layer of Milinex (Mylar) would offer more protection than a cotton or alpha cellulose board , but not total protection.

[Roboframer]

Mylar and an extra mount - to make a double mount with the old one on top, but you would have to make the aperture larger in the old mount, or maybe cover more of the image, which may not be a bad thing if there is some acid burn and the signature is not affected.

But now we are adding cost.

[JFeig]

I was suggesting a barrior of the Mylar and the original mount....... not a second mount and the mylar below the original mount.

[Roboframer]

I was suggesting adding an archival mount for protection and isolating it from the old one with Mylar.

How does the watercolour paper test for acid?

[Not your average framer]

Hi,

There is some degree of risk in trying to re-cut an acid burnt mount, depending on the degree of acid burn. It may no longer have sufficient structural strength to cut cleanly. Also a new mount underneath is unlikely to look right with an old one.

I do have one possible long-shot you might like to check out. Conservation Resources in Horspath (near Oxford) sell (or used to sell) a spray-on solvent based acid neutraliser called CHC or something similar. I've never used it and don't know how it would work on something as thick as mountboard, but not containing any water at all it may be a possibe solution to the problem. I suspect it may not be at all cheap!
Cheers,
Mark

[Coxby]

Introducing a Mular or DuraLar barrier as well as using barrier board sounds like the best I can offer the client. Can you recommend a retailer for either and does it come with a pressure sensitive adhesive on one/both sides?

[Roboframer]

Hi,

There is some degree of risk in trying to re-cut an acid burnt mount, depending on the degree of acid burn. It may no longer have sufficient structural strength to cut cleanly. Also a new mount underneath is unlikely to look right with an old one.
Mark

Was assuming that as the mount needed to be tested for acidity that it was not that old, otherwise it is usually obvious from the brown bevel! Even if new, if standard mountboard has been used, I can tell at a glance.

Bainbridge do a range of artcare boards with cream bevels, look like crap but are actually quality!

An old acid filled board that has gone brittle, I would not try and cut. But if it had 'acid burn' it would not need to be tested would it!

I'm afraid that I can get a bit "Basil" when a customer has a problem I can solve but is not willing to pay for it and sometimes takes so long in seeking cheap(er) alternatives that I add a fitting charge of £15 per 15 minutes after (and including) the first half hour.

[Not your average framer]

Hi Roboframer,

I hadn't thought about like that - Too hasty in jumping to conclusions, I think.
Cheers,
Mark