Wet mounting prints

by John A. Cook © 2003 for largeformatphotography.info

Summary: This is a description of the technique my studio used to wet-mount large black-and-white murals around 1960. While some of the materials have changed, I believe the basic technique remains valid.

Just a word about the prints. We used Kodak Mural R paper in rolls about 40" wide. While this paper is no longer made, something very similar may be available from Luminos in NYC: http://www.luminos.com

The value of this paper was that its base was entirely cotton fiber, with no wood pulp. When it got wet it went totally limp, like a wet bedsheet. You could not ding, crack nor crease the surface, making it foolproof to handle. And it could be folded and unfolded to be developed in a small deep tray, like a restaurant bus-pan. We also had large home-made wooden forms, lined with plastic painter's drop-cloths.

Development was "to completion", about 5 minutes in Dektol, to allow for even development in spite of the delay in wetting parts of the print while unfolding. We didn't use an easel for exposing such a large print. The paper was pinned, with upholsterer's T-pins, to a sheet of Homasote which we obtained from a lumberyard.

Drying and mounting fiber-based black-and-white photographic prints has always been difficult. It's almost impossible to get a large fiber print to dry completely flat. Large dry-mount presses cost several thousand dollars. And applying pressure to wavy prints often causes permanent damage from wrinkles and creases.

One solution is to mount the print with glue while still damp and soft. This technique has the added advantage that the print can be repositioned and slid-around indefinitely.

Our technique for the murals mentioned above, involved coating 1/8" double-tempered Masonite (smooth both sides) with Elmer's white glue. Today, I would recommend substituting Gatorfoam(r) (not Fom-Cor(r)) as it is much lighter than Masonite and completely waterproof. Fom-Cor(r) is much too soft and will dent and bend.

If you can't find a local source for Gatorfoam(r), contact Modern Plastics at: http://modernplastics.com It is made in 4'x8' sheets, up to an inch thick, in white, black or natural. You can easily cut it with a crosscut or plywood blade on a table saw. They will also cut it to size for you. I believe Light Impressions: http://www.lightimpressionsdirect.com/servlet/OnlineShopping also has it in a few standard sizes.

If you cut your own board, dust it very, very carefully with a tack-rag. The tiny particles of white sawdust are nearly invisible, but will cause a noticable "pimple" in the mounted print if you miss one.

We bought the Elmer's glue in gallon jugs and diluted it very slightly with water, no more than 1" of water in the jug. The glue was then heavily applied to the Masonite with a paint roller and allowed to dry completely. After dry, some of the higher peaks left by the roller texture were lightly sanded off. Don't go crazy here - the more glue on the board the better.

We would then pull the mural prints from the wash, dripping, sopping wet and lay them over the Masonite. (It helps if you have on staff a bullfighter who's good with cape-work.) The prints were always larger, by at least three inches per side than the board. Paper stretches (1/2" per yard) when wet and shrinks back somewhat as it dries. You need a large slop factor for this method. A 40" print will never match a 40" board. And then there were the shadows left by those T-pins on the print.

Working from the center outward, squeegee the water off the print. We worked over a concrete floor in an old factory building. You may need plastic drop-cloths. The water will re-wet and re-activate the dry Elmer's glue and make the print adhere to the board. The print will shrink as it dries, pulling out any small bubbles or wrinkles.

We sometimes used to carefully glue and wrap the excess print paper around the edges of the Masonite and stick it to the back of the board. This gave a nice clean look to prints which were not to be framed. Otherwise, we would trim the print to the edge of the board with a single-edge razor blade. To keep the Masonite from bowing due to the shrinking print, we sometimes glued another wet blank print to the back to pull against it.

Then allow to dry overnight, flat on the floor with the print side up. No pressure necessary.

After everything was completely dry, we could varnish (now use water-based product for non-amber clarity) the print to make it washable.

I believe this technique can be used with modern photo paper as well. Not sure about trying to wrap stiff double-weight paper around the board. And a semi-matte or matte surface (Luminos "Charcoal" or "Tapestry") would be closer to the old mural paper. Photo linen from Luminos would also be excellent, albeit expensive.

I would also try drying a print with a squeegee and sponge until just damp and then applying it with fresh wet glue as in wallpapering. Cellulose wallpaper paste might be substituted for Elmer's.

PVA is the generic chemical name for this type of adhesive, which is also available in an archival variety, the claim-to-fame of which is that it is supposed to remain flexible and not turn brittle. However, I have a print from 35 years ago glued with Elmer's which is still just fine.

Anyway, that's how we used to mount prints without a monster press when JFK and Jackie were still running Camelot.

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