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Would mounting a print to glass or acrylic be harmful??

See R , Apr 03, 2007; 07:34 p.m.

A comment made in a separate post warrants further exploration. The question is whether mounting any print to glass or acrylic would be harmful to the print over time. Glass is a highly stable material, which if clean, will not leach any compounds that would be harmful to a print. Glass is made mostly of silica and is impregnated with metal ions. All of the materials in glass are, for the purposes of this discussion, stabilized and nonreactive, and certainly won't compramise the archival nature of any print from a chemical reactive standpoint. I should think this is the same with at least most acrylics, but I'm not quite positive about that. If anyone knows why acrylic would not be an archival mounting surface from a chemical reactive standpoint, please explain in detail.

The only way I would think, in theory at least, that glass or acrylic, if used for mounting would be harmful would be either by way of thermal expansion, ie. due to a large coefficient of thermal expansion (COE), or by way of transmittance of UV, light, or other EM radiation. With a high COE, moderate changes in temperature could potentially cause contractions and expansions that over time would place internal stress on the printed paper (or other material) and compramise it's structural integrity. Perhaps something like 100% cotton museum board escapes this fate because it is not rigid as are glass and polymers such as acrylic, and as such does not expand and contract on a macroscopic level with changes in temperature and therefore doesn't place any stress on the printed material.

With these things said, if anyone has any evidenced-based thoughts as to why glass or acrylic are not archival mounting materials, please describe...thanks!


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Jim Strutz - Anchorage, AK , Apr 03, 2007; 07:46 p.m.

There are places in the west where anything displayed on glass cannot be considered archival. It seems to attract punks with BB guns.

Bill Van Antwerp , Apr 03, 2007; 07:47 p.m.

Glass is certainly archival in the sense that the glass won't do anything to the print. The real problem is the opposite, prints stick to the glass. Both silver gelatin paper and inkjet paper will stick to glass, particularly if the print is thermally cycled or exposed to UV light.


Edward Ingold , Apr 03, 2007; 07:50 p.m.

To use an old phrase, "It's not the heat, it's the humidity". That certainly holds true for any fiber based print or gel type coating. Ordinary paper can change dimensions as much as 1/8 inch per foot with humidity. If the backing were rigid, as with glass or acrylic, the paper or coating would have to give, probably causing cracking or peeling. Mount the print on matting board or acid-free foamcore, which are sufficiently flexible to prevent cracking.

Helen Bach , Apr 03, 2007; 07:53 p.m.

Never mind the punks, I am more concerned about the adhesive used for face mounting - I've followed the trend for face mounting onto acrylic. There's also the idea that archival mounts should be reversible (ie the print can be removed) but that doesn't bother me - I'm not claiming that my face mounted prints are archival.

See R , Apr 03, 2007; 08:18 p.m.


I'm really glad you mentioned humidity...I totally didn't think of that. Acrylic, however, has the advantage over matboard or foamcore (my original mounting material for my pieces) that it can be formed and polished.

I suppose I could get around the humidity issue with a dessicant.

Also, I'm wondering in what geographic region you've observed 1/8 inch per foot changes in ordinary paper and I wonder if this would apply to fine art inkjet papers?

Helen Bach , Apr 03, 2007; 09:43 p.m.


Which side of the print is the glass or acrylic going on? If you are face mounting to acrylic - very common these days - the print is sandwiched between the acrylic and mounting board or Sintra or similar. Heat and humidity are not a problem.

Best, Helen

Edward Ingold , Apr 03, 2007; 09:49 p.m.

Chicago - the humidity range is enormous, summer to winter. That figure would be large, but 1/16" cross-grain is not unusual for machine-layed paper like newsprint and label stock. Hand-made paper might be less, since the grain is random

Rick Covert , Apr 03, 2007; 11:27 p.m.

If you want to frame a photo without a mat you can use a spacer to raise the glass away from the photo.


See R , Apr 03, 2007; 11:54 p.m.

Helen, the print actually went on top of the acrylic. If I front mount then I have a problem with reflections. I really like to use glare reduction glass in front of matte paper.

Bill, thanks for the warnings about glass.

Edward, my home town! I am now in California (for 16 years), so there is less humidity to contend with. Still I now think I should be smart to avoid mounting to plexi or making high-maintenance pieces requiring dessicant!

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