Protecting Inkjet Prints with Films, Coatings, and Sprays
With the wide-format inkjet printable media from Freedom Paper, you can produce everything from postcards and presentation prints to fine art and wall murals on the wide format inkjet printer in your office or studio.
But to create indoor or outdoor display graphics, art prints, or heirloom photo prints, it’s essential to understand different methods of protecting inkjet prints.
This knowledge is especially important if you use an older model wide format inkjet printer that uses dye inks.
Even if you use a new photo/graphics wide format inkjet printer that uses more fade-resistant pigment inks, you still must know how to protect the prints from scratches, abrasion, and airborne pollutants.
Here are a few of the most popular options:
Aerosol Spray Lacquers
Protective sprays provide a fast, easy way to protect inkjet prints on fine art papers from abrasion, fingerprints, UV light, and airborne pollutants. These sprays are commonly used with smaller prints on art papers or photo papers with porous coatings. Spray-on coatings are particularly popular for prints that are designed to be handled, such as notecards, album pages, or portfolio prints.
The aerosol spray forms a fine film that doesn’t affect the structure of the paper. Unfortunately, the spray lacquers required to protect water-soluble dye inks contain solvents. This means you should apply it in a well-ventilated area, wear goggles, and/or use a respirator that meets OSHA and NIOSH safety requirements.
One product Freedom Paper recommends for users of aqueous dye inks is Moab Desert Varnish. This spray improves waterfastness, dries quickly, and adds UV-resistance and scratch protection. If you apply 2 light coats (as recommended), a 13.5-oz. can will cover about 60 A4 prints. After the coating dries, you won’t even know it’s there! But your prints will be much more resistant to ordinary handling. Hahnemuehle Protective Spray is another good option for protecting prints on inkjet art paper.
Liquid Clearcoats and Varnishes
A properly formulated clearcoat can add years to the life of prints on canvas or vinyl by protecting them from UV light, airborne pollutants, abrasion, and water damage. After the liquid coating dries on the surface of the print, it forms a thin, barrier film that protects the ink and the canvas, vinyl, wallcovering material, or paper beneath it.
Different formulations of liquid coatings exist to meet the different display requirements of inkjet canvas, indoor wallcoverings, and outdoor signs.
For example, clearcoats for inkjet canvas (which are also referred to as varnishes or veneers) must remain supple enough not to crack when the canvas is stretched around the wood bars of a gallery wraps. Clearcoats for fine art applications are made to penetrate the canvas without causing color shifts or other undesirable interactions with the ink-receptive coating on the surface of the canvas.
Clearcoats for outdoor signs must be rugged enough to withstand weather hazards such as driving rains and windborne hail, exhaust fumes, and other airborne particles and pollutants.
If you print color images with aqueous dye inks, you must use a solvent-based clearcoat such as ClearJet Series FA for art or Original ClearJet for signs.
If you print images with aqueous pigment inks, latex inks, or eco-solvent inks on water-resistant canvases, vinyl banners, or adhesive materials for outdoor signage, you can apply a water-based clearcoat such as ClearShield or ClearShield Type C.
Two water-based clearcoats specifically formulated for water-resistant inkjet canvases include Museo ENHANCE™ and Hahnemuehle Varnish. The coatings are available in satin, gloss, and matte finishes. The gloss coatings can increase the richness of the blacks and colors.
Before applying a clearcoat, it’s always a good idea to pretest your digital prints to ensure that you are using the correct formulation. Inadvertently using a water-based clearcoat with aqueous dye inks would cause the inks to bleed.
If you only want to coat a few prints, you can use a high-density foam roller to apply the canvas. Print shops that coat higher volumes of canvas prints typically build a spray booth and use a high-volume, low pressure (HVLP) spray gun to coat the canvases.
Liquid laminators have been designed to automatically apply thin even layers of clearcoats to vinyl, canvas, or superwide graphics. Drytac’s Elite Coater is a tabletop flood coater that can apply a water-based clearcoat to fine art papers and canvas up to 44 inches wide. These mechanical devices must be used in temperature and humidity-controlled, dust-free environments.
A huge variety of clear, adhesive-backed films have been designed to protect to the surface of all sorts of printed documents, including inkjet prints.
Lower-cost “hot” laminating films are made with heat-stable polyester films. The adhesives of “hot laminating films” are activated by the heat and pressure of laminators with heated rollers. A typical hot laminating film for printed documents activates at temperatures between 210 and 240 degrees. Because these high levels of heat can damage some types of inkjet prints, “low melt” or “heat-assist” films have been developed.
“Low melt” films have heat-activated adhesives that can be applied at temperatures between 185 and 195 degrees. “Heat assist” films have pressure-sensitive adhesives and liners and applied with hot-roll laminators at temperatures of 185 to 195 degrees.
“Cold laminating films” can be made of PVC, polyester, polycarbonate, polyolefin, or other substrates. These films use more aggressive, pressure-sensitive adhesives that are protected with a release liner until they are applied. Cold laminating films typically cost more than hot laminating films, but they can be applied with less costly, easier-to-operate non-heated laminators.
For smaller graphics such as yard signs, you can use a wide-format squeegee from sign-supply companies such as Sign Warehouse to apply a pressure-sensitive laminating film.
Laminating films vary greatly in cost, durability, flexibility, and their resistance to UV light.
In order to protect dye-ink prints from the damaging effects of moisture and humidity, it’s best to “encapsulate” the print between two sheets of laminating film that are slightly larger than the print. This keeps moisture from seeping in around the edges.
Most prints output on fine art and photo papers are designed to be displayed in frames. To keep the prints from fading or yellowing, it’s best to use a framing glass or acrylic sheet that has UV filters. The UV filters not only can slow down the fade rate of inks, but can also keep optical brightening agents (OBAs) used to manufacture the paper or canvas from wearing out.
Acrylic glazing such as Plexiglas® weighs less than glass and is less likely to shatter. Acrylic is popular for framing large-format prints that will be shipped or displayed in children’s rooms. Some museums use acrylic
Glass is typically less expensive and more scratch resistant than acrylic. But it is less optically pure and may show a green or yellowish tint.
The Frame Destinations website includes an excellent page that describes the pros and cons of using acrylic and glass for short-term and longer-term print protection.
When preparing images for framing, it’s essential to use archival-grade mat boards and adhesives. If you apply a water-based adhesive (such as starch pastes for hinging) to the back of printed areas in a dye inkjet prints, the moisture can migrate and cause the colorants to bleed. It’s also important to avoid the use of pressure-sensitive adhesives to the front surface of an inkjet print.
Storage Boxes and Portfolios
Another way to protect inkjet prints is to mat them and store them away from the air and light in an enclosure or portfolio that meets the ISO Standard 18902 for albums, framing, and storage materials for processed imaging materials.
The standard specifies that enclosures be acid-free, be lignin-free, and not include rubber adhesives or chlorinated, plasticized or cellulosic plastics. The enclosure should also contain 2% alkaline reserve to buffer the paper against acids in the environment and pass the Photographic Activity Test developed by the Image Permanence Institute to evaluates possible chemical interactions between enclosures and photographic images after long-term storage.
According to the Image Permanence Institute, the ISO Standard 18902 isn’t totally satisfactory for inkjet prints: “It is more difficult to select safe enclosures for inkjet because of the diversity of ink and paper formulations used as well as their individual chemical and physical responses to enclosure materials.” Some inkjet prints might be subject to adhesive-induced yellowing, bleed, and abrasion.
Inkjet photo and art prints should never be stored in vinyl plastic enclosures. Only smooth, polyester sheeting is safe for contact with print surface.
If you have additional questions about protecting inkjet printable media, please give us a call or leave a comment below. If you have any tips or suggestions related to inkjet-print protection, please send them our way.
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