Pressure sensitive adhesives...they're not new, you say, no, they've been around for years. But the incidence of utilizing them in framing applications has been increasing. Since the advent of digital imaging, computer printers and thermographics (including FAXs) framer consciousness about heat sensitivities may steer them away from dry mounting. Hence, the use of spray, wet and pressure sensitive adhesives has been increasing.
New products have hit the framing market, often migrating from other industries such as graphic design, to fill our growing needs. In the hierarchy of adhesive longevity, pressure sensitive films and boards used in conjunction with cold vacuum frames fall right behind dry mounting. Simplicity of application, cleanliness and versatility make them a common choice, though pressure sensitive boards get knocked out of contention when clarity of the adhesive is part of the primary selection requirement.
This clarity issue brings me to the root of this month's article. "Ghosting" is the undesired bleeding through of text or pictures from the verso side of a mounting. The most commonly framed source of ghosting comes from newspaper clippings or magazine articles. The paper used for printing is inexpensive, porous and thin enough to readily see the printing from the back side through to the front.
The solution is to simply mount onto the same color surface as the dominant color on the back of the clipping, usually black. This hides the black/white contrast rendering the verso text "gone".
Charging for Black Substrates
Dealing with the ghosting issue is not really an "issue" at all, but rather an opportunity for increased consumer awareness education AND additional profits. Anytime mounting is done on a substrate other than your standard choice (foam, chipboard, mount board, generally white or neutral) a slightly higher price should be charged for the "special" addition.
Some framers have a real problem charging more for mounting onto different colored substrates when their costs may be lower than their regular board. Even if you elect not to charge for the different colored substrate you should use it as a consumer "good will" sales tool for your best customers then not charge them the extra.
The best way to sell anything is with an in-store sample (photo 1), which is important for two reasons. First to illustrate the camouflage of the verso printing when placed on a dark surface, and second point out the graying of the white sheet or off-white newspaper when mounted onto a dark substrate.
In-store samples illustrate what ghosting is, how to get rid of it, and that the dark substrate will darken the overall appearance.
Clarity of the Issue
When creating a sampler, either black on a white substrate or white added to black substrate will work. I prefer to add the black paper to the white base. Begin with an 8"x10" or 11"x14" piece of white mat, mounting, or foam board. Both the black triangle and the magazine page will require mounting to the selected substrate. The bottom black paper may be mounted using any desired adhesive or process (spray, wet, pressure-sensitive, dry) because the black sheet is not able to be seen through. Though usually the same clear film, spray or pressure-sensitive will be used for both.
Boards and Films
Pressure-sensitive mount and foam boards are generally found with their release liner on white boards. In order to use them to prevent ghosting, a colored sheet would routinely need to be first added to the cover the white board, then a clear film would be needed to allow the color from the substrate to dominate the text ghosting. This precludes the ability to create a mounting on a different colored board or substrate...as with a project as illustrated without another clear adhesive anyway.
On the other hand, pressure-sensitive films are available in sheets and on rolls, such as 3Ms PMA is a film on a roll applied to a release liner. The film is rather delicate and applies best when directly transferred to the desired mountable. The adhesive is easily pulled apart by attempting to handle it.
Sheet films, such as Crescent Perfect Mount Film, are a very thin polymer sheet coated on both sides with pressure-sensitive adhesive. This allows the sheet to be handled more without pulling apart, though it does still stick to your fingers and could wrinkle. In either type care should be taken and the best results when using films are to apply them to the pieces to be mounted rather than attempting to handle them at all.
Preparing the Contrasting Diagonal Substrate
Cut a piece of lightfast (non-fading) black paper the size of the desired sample. Do not use construction paper for its light fugitive nature. The sample shows a sheet of Raven Black Crescent Colored Art Paper cut the same size of the board. Split the black paper diagonally or in half to achieve the necessary comparison/contrast between the two substrate surfaces colors.
Two different brands of pressure-sensitive films have been used in this article for illustration. The black paper was applied with 3M PMA/Positionable Mounting Adhesive. Gently lift the mounting triangle which has picked up the self-shaping adhesive and align it onto the sized board. Cover with the release sheet and either feed through a 3M roller machine, brayer or place in cold vacuum frame for mounting.
Applying Adhesive to the Magazine Page
The two-liner pressure-sensitive films (Crescent Perfect Mount) have a thin sheet of clear adhesive film between liners. Size the film unit and remove one of the release liners by laying the sheet flat on a hard surface and rolling the liner from the film. Position the magazine sheet on top of the exposed adhesive film, replace release liner and brayer or squeegee in place. Since there is a backing liner and there is a stabilizer layer between the adhesive films, this film is not self-shaping and requires trimming to its actual dimensions. Remove the article/adhesive film from the backing release liner by laying the piece flat, face up and rolling the sheet from the liner. Peeling it from a flat during removal better prevents wrinkles in the film.
Position the magazine page onto the two-tone substrate. This film is repositionable allowing for adjustments prior to burnishing or curing. Final burnishing, brayering or cold vacuuming will affix in place. The piece should then be weighted and let set 24 hours to achieve full bond. Leave a trim edge surrounding the mounting to showcase the black vs. white substrate variations.
The same elements of time, temperature, pressure and moisture will come into play with pressure-sensitives as with any type of mounting, but in different extremes. Time will be the curing time for the final bond to occur. Temperature is a player when the materials become too cold, but check with manufacturers. This element has less impact when using pressure-sensitives than the other adhesives. Pressure is the weighting of the project during the curing process, whether 8 or 24 hours. Moisture always plays a part, regardless of the adhesive. Nothing ever wants to stick to excessively damp boards, so watch your storage. If the boards feel cool, that generally means they are damp.
So, Why A Pressure-Sensitive?
Since the above sampler is heat tolerable, the entire project could be dry mounted using a clear adhesive film, but what if the customer brought in a thermographic FAX or flier with thermo printing? Or something thin with lettering on two sides that is of unknown origin, maybe oil pastel? Grab your spray can, wet glue or pressure-sensitive materials.
If there remains any question in your mind "is it heat sensitive?", pressure sensitive adhesive films are becoming more and more versatile, long lasting and cleaner to use than some of the alternatives. They possess the clear adhesive necessary to control the ghosting and are a terrific alternative method for so many of the questionable projects of the 90s.
Stay tuned next month for more ideas with pressure-sensitives in our annual photo issue.
Copyright © 1996 Chris A Paschke
For more articles on mounting basics look under the mounting section in Articles by Subject.
Additional information on all types of mounting is found in:
The Mounting and Laminating Handbook, Second Edition, 2002,
The Mounting And Laminating Handbook, Third Edition, 2008 and
Creative Mounting, Wrapping, And Laminating, 2000 will teach you everything you need to know about getting the most from your dry mount equipment and materials as an innovative frame designer.
All books are available from Designs Ink Publishing through this website.
Chris A Paschke, CPF GCF
Designs Ink Publishing
785 Tucker Road, Suite G-183
Tehachapi, CA 93561