Tuesday, January 28, 2014

On Dry Mounting

We get a lot of questions about dry mounting, so I'm going to address the topic as best I can. Keep in mind Poster Mountain does not offer this service, so the information you're getting here is the result of experience-based speculation and some internet research. So here we go.

Compared with linen backing, paper backing, or the gelatin process (all of which we offer,) dry mounting is inexpensive. You can do it yourself at home or you can have your framer do it.

Dry mounting involves fusing your print or poster to a sturdy backing with dry mount paper or spray mount adhesive. The dry mount paper goes between the backing and the print, and it's fused using either a heat press or a standard fabric iron. The backing can be a sheet of wood, plastic, foam core, or cardboard.

Dry mounting is technically irreversible. You cannot undo it, although WE usually can. Once the print is on there, you are not getting it offa there. Some types of dry mount paper claim to be reversible. I don't know. In my twelve-odd years restoring posters, I can't say I've heard of reversible dry mounting. On the streets of conservation, the general consensus is AVOID.

Here's why it's bad:
You may not care whether that print ever comes off the backing, but if there is a flood or a fire or even just a spill, even if you just move to humid Florida, the paper will get damaged, moldy, brittle, brown, stained, wrinkly, or wavy. Paper is fragile and a frame is not a hermetically sealed chamber. The elements will get in.

In order to repair a damaged print, you're going to have to take it to a conservator like Poster Mountain. In order for us to fix the print, we'll need to take it off the backing. And if it's dry mounted, we often won't be able to remove it without a lot of labor and even some invasive damage to the print (read: invasive damage to your wallet.)

Here are a few images of dry mounted misery. Sensitive viewers beware.

Does this look good? Does it? This Amelie poster is beyond help due to the ravages of dry mounting and the low value of the poster. Believe me, we COULD remove it from the board but would take 2 people about 6 hours and this poster just is not worth that much time, easy to replace with a new one.
Here you can see the anatomy of a dry mount, with the poster on top, nasty horrid dry mounting paper in the middle, and foam core board at bottom.

The first battle in a dry mount war is the backing. John has clamped this piece face-down to a table and is shaving down the foam core with a sharpened spatula.

Once the backing has been thinned down to a flexible layer, he will be able to peel it off without danger of bending the poster. Since this poster is glossy, he has to be careful to keep it flat since many glossy inks tend to flake off when the paper is bent or curled.

In this particular example, a solvent called bestine is poured over the remnants of foam core and dry mount paper. This loosens the disgusting adhesive. When demounting a traditionally linen backed poster we use water to loosen the glue, but not with a dry mount. This method will not work on all types of dry mounting tissues, some are wax based and require the use of heat!

John lays a sheet of mylar over the poster to let the bestine soak in without evaporating.

The dry mount paper came off pretty easily in this case, but...

Now John has to remove a very thick coating of adhesive.

Dude, ew.

There are many variations on removing a dry mount. Here they will be working from the front. The poster is resting on a board that has been elevated on one side to let the bestine run down.

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The poster is gently lifted up off the backing. You can see where the bestine has seeped down behind the dry mount paper.

We still need to buy some size-small rubber gloves. Here Robin peels back the dry mount paper to reveal tape! Yay, more stuff to pick at!

Here's what the dry mount paper looks like once it's moulted. Yech.

Your print may not have much value in today's market, but you'd be surprised what fifty or a hundred years can do for the value of ephemera. Linen backing really is the best way to mount paper. It's archival and reversible. If you take the benefits into consideration, and the avoided potential headaches, linen backing is easily worth the extra money.


  1. The adhesive has dried out and the poster is barely hanging on. Can it be reglued to the existing dry mount? It is about 25 years old.

  2. The adhesive has dried out and the poster is barely hanging on. Can it be reglued to the existing dry mount? It is about 25 years old.

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