When considering the proper way to mount artwork, you might think that protecting the artwork's long term value is of paramount importance. Some artwork, however, is not worth protecting, either because it is already acidic and therefore will deteriorate in any case, given enough time, or because it can be readily reproduced and is therefore unlikely to ever become rare and valuable.
In these instances, it is more important to get a flat, firm mount, and the best of way of achieving that is to coat the back of the artwork with a uniform coat of adhesive and stick it down to a flat, lightweight substrate like foamboard.
Frame shops routinely coat and adhere low value artwork to foamboard using a mechanical dry mount press. But dry mounting can be prohibitively expensive for the do-it-yourself. An obvious low priced alternative is spray mounting using a spray adhesive. But spray adhesives can be unpleasantly messy and if you are not careful to use the repositionable type your artwork will stick permanently to the mounting board the moment it contacts the adhesive.
A better option is Positionable Mounting Adhesive or PMA. PMA is cleaner and easier than spray mounting and much less expensive than dry mounting. Although a machine can be purchased for applying it, PMA can be applied manually with relative ease.
PMA is a 50-foot sheet of transferable adhesive on a roll. The rolls are available in 11", 16" and 24" widths. For larger artwork, two swatches can be applied side-by-side with a slight overlap. No evidence of a seam will be visible. The package also contains release paper, a plastic burnishing squeegee and instructions.
To use PMA, begin by unrolling a length larger than the item you are mounting and cut it with a razor blade. Then place the artwork face up on the tacky side of the sheet. Next, place the release paper over the artwork and burnish through it, using the burnishing squeegee. The action of burnishing transfers the adhesive from the sheet onto the back of the artwork.
After burnishing, peel the artwork away from the sheet. The adhesive will transfer from the sheet to the back of the artwork in a uniform coat
Finally, position the artwork on foamboard or some other mounting substrate. If you are unhappy with the positioning, peel it up and try again. The artwork will peel up cleanly because PMA is fully repositionable until you burnish it a second time. Once you are satisfied, place the release paper over the artwork and burnish to adhere.
PMA is ideal for mounting posters and photographic prints that are easily reproducable from a negative or a disk. It mimics the flat, firm mount achieved by using a mechanical dry mount press, but at a fraction of the cost. For artwork that is unlikely to increase in value over time PMA should be your first choice for a quality, low cost permanent mount.