Conservation Clear glass


CGF, Certified Grumble Framer
Sep 22, 2003
Atlanta, Georgia
I have a customer that has two posters she wants each in a metal frame. One is a limited edition and the other is not. She wants the posters without a mat - so the posters will reach all the way to the frame. I know there should be an air gap between the image and the glass. Inquiring around local frame shops, both of them said you don't need an air space if using conservation clear glass. Is this true? I was planning to use a 3/16" FrameSpace to create an air space. Any opinions or suggestions would be appreciated.
Thanks, Dan

Ron Eggers

SPFG, Supreme Picture Framing God
Jul 6, 2001
Hi Dan,

The required airspace has nothing to do with UV filtering. It is there to provide some thermal insulation to protect the print from changes in temperature and humidity. It is necessary with any type of glass.

The problem with using spacers to provide that airspace is that it puts pressure around the outside edge of the print and interferes with the inevitable expansion and contraction of any unmounted paper. It will buckle.

Others will disagree, but I think that what your customer wants cannot be done properly without drymounting the posters. A limited edition poster should probably not be dry-mounted, so it should be matted, or at least floated on an oversize board with spacers that don't touch the poster.

BTW, those other framers you talked to should be ashamed.

Cliff Wilson

SGF, Supreme Grumble Framer
May 14, 2002
Worcester, MA
I agree with Ron that a mat would be MUCH better, but I would use the spacers as you planned if that's what the customer wanted. I understand Ron's reservation, but the spacers are better than no spacer. I would v-hinge the poster at the top then make sure the points are not in tightly. I believe this enables "some" expansion and movement under the spacers.

For the LE I might suggest constructing your own "spacers" with strips of 8 ply. But, the rest of the package should be the same.

And those other framers ... are tar and feathers still available in Georgia??


SGF, Supreme Grumble Framer
Mar 23, 2001
Wilmington, DE
Everything that Ron and Cliff have said is true
and applicable. This is the sort of situation in
which the client's requests pose serious preservation problems. Most posters in frames,
even with window mats, will not stay flat without
some sort of mounting and thus, Ron's suggestion
of mounting the open edition poster is more likely
to satisify the client. Remember, most offset
printing is far from light-fast and the poster
is likely to fade (even with UV filtration) long
before its paper degrades. One might hope that
the limited edition poster has been printed with
better quality ink and that matting, it as Cliff
suggested, will restrain it at its edges. It is
still likely to change shape and touch the
glazing. Using acrylic sheet will diminish the thermal issues that Ron raised, but the client should be warned not to expect the poster to stay flat.


AndyPan CPF

MGF, Master Grumble Framer
Forum Donor
Jun 29, 2002
Lincoln, RI
Get The Picture
This actually brings up an issue for me. I had a customer who came in yesterday with a print that he just recently purchased. He did not want to do any matting, because the piece was rather large. We discussed mounting options, and I asked him if the print was valuable, and he said yes. Acid-free drymounting came up and we discussed that. Then I asked him EXACTLY how valuable the print was. Apparently he spent abut $600 on it, and actually received a letter shortly after that the print had gone up in value by about $150 or so. Learning that, I explained that the print absolutely should NOT be, in any way, permanently mounted.

He was concerned about buckling and rippling. We decided to simply back the print with Artcare foam, and lay the glass directly on the print, no spacers. The print's surface is pretty flat, not glossy at all. I am pretty sure that this is the only way that we can keep the print as flat as possible, though the customer was warned that there will be some slight rippling, which he was okay with. Have I done wrong here? Should spacers have been included anyway? The issue of the spacers causing pressure to be applied at the edges is of some concern to me. Is there another option I could have gone with?


SGF, Supreme Grumble Framer
Oct 10, 2000
Andy, Ideally, the piece should be matted. I understand your logic, but right is right. If he insists on no mat, then it has to have spacers.

When will customers who buy art understand that some ripples are acceptable? If they want flat pictures, they should be buying posters.

Bill Henry-

SPFG, Supreme Picture Framing God
Aug 17, 2002
Boondock Bowerbank, ME
Retired from the grind
If Dan frequents the Grumble often, he will soon come to realize that there is seldom consensus among us. So, I will suggest a contrarian view:

I shall wade in in support of Andy, here. While I agree that a spacer would be the least objectionable solution given the constraints of the customer, I have no problem with simply “sandwiching” the art between ArtCare (or some such) and the glass.

Assuming the art is neither a photo nor printed on a high gloss paper where the emulsion or gloss might absorb moisture, swell and stick to the glass, I see no problem with a sandwich. Sure, it won’t be able to “breathe”, but so what?

Not only will the sandwich help keep the art a bit flatter, but the glass itself will have less stress on it than it would being held only on four sides by the spacer.


Comfort Badger
Forum Support Team
Forum Donor
Sep 1, 2000
Jacksonville Beach, FL USA
Sunshine Frames
Another possible consideration due to your regional climate is condensation. The contact points between the glazing and the paper is where condensation will occur. Going from the relatively controlled atmosphere of your shop to the trunk of their car can prove to be problematic.
Pigments in contact with glass can be burnished from the vibration of transport, developing hot spots in the finish, and not allowing room for expansion is a guaranteed way to cockle a print.

This reminds me of the time when some folks were selling Non-Glare glass as UV protection. Yet another myth.