Finding the Right Solution for Long-Term Graphic Survival
By Thomas Franklin
The soaring popularity of outdoor advertising spotlights graphics capable of withstanding the elements. But even signage not destined for the great outdoors is expected to hold up—in public places under pawing hands, on floors and skidding feet, or on windows near harsh lighting.
Bringing a high-end graphic to market means correctly matching a substrate with an ink and laminate that meets and exceeds customer longevity and style expectations. Print service providers (PSPs) face a daunting array of choices and each piece must fit together for the best result.
“It looks like a simple sandwich, but that’s not the case,” says Tim Boxeth, marketing manager, 3M Graphics Market Center. Getting the components to work well together is crucial. A graphic is only as strong as the weakest piece of the sandwich, notes Andrew Oransky, director of product management, Roland DGA Corporation.
Understanding the performance capabilities of inks, media, and laminates are essential not only for ensuring the survival of the graphic, but good business sense.
“It’s important to understand customer expectations with regard to life expectancy of the print so you don’t end up spending too much money on the combination of ink, media, and laminate. You don’t want bid yourself out of a job,” explains David Conrad, senior product manager, equipment, Neschen Americas. “Knowing what materials to use to achieve the desired appearance and durability of a printed image allows PSPs to maximize profitability.”
Ink in the Chain“Ink can be the weakest link in a graphic,” shares Jennifer Greenquist, inks/warranty business manager, 3M. Each technology—solvent, eco-solvent, UV, latex, and aqueous—brings unique qualities to the table. With the exception of aqueous, other inks tend to offer a minimum of two years outdoor life unlaminated—except in hot, arid climates.
Most mild- and eco-solvent inks offer two and even up to three years outdoor durability on vinyl without lamination depending on the climate, says Steve Igoe, North American sales manager, Bordeaux Digital PrintInk Ltd. “We talk about eco-solvent durability of up to three years unlaminated, and typically five years laminated,” explains Roland’s Oransky.
Aqueous prints, while not suitable for outdoor applications without lamination, deliver very long lifespans indoors. Fine art prints with aqueous inks on canvas last over 100 years. Water-based inks remain popular for indoor applications, adds Igoe.
Solvent printers using Hewlett-Packard (HP) Scitex solvent inks achieve two years outdoor ink durability, says Don Knox, U.S. director of sales, large format printing, HP Graphics Solutions Business. Likewise, UV inks provide roughly two years outdoor durability, he adds. For 3M’s part, they provide the same warranty for solvent and UV inks as far as life expectancy, notes Greenquist.
While UV inks are finding favor in outdoor applications, they are not suitable for all media. UV turns vinyl brittle as it cures, making it unsuitable for vehicle wraps. “It’s possible to get more flexible output with the latest and greatest UV formulations, explains Ritchie Daize, international product manager, Arlon, Inc.
Latex ink seems, “very promising. It’s similar to a solvent but carried to the vinyl using steam. You can deliver the pigment without harming the adhesive. The testing that I’ve seen is very encouraging,” shares Daize. What’s more, latex inks work on most media designed for solvent printing. “HP Latex Inks offer the durability of eco-solvent inks with display permanence up to three years unlaminated and up to five years laminated,” adds Knox.
To Laminate or Not to LaminateIn some instances, two years of outdoor life may not be long enough. There are a variety of circumstances where lamination is necessary. The obvious protection benefits include UV, abrasion, and graffiti resistance; specialty coatings for unique applications such as floor graphics—to prevent people from slipping; and window film, which requires specially perforated top coats. Depending on where the graphic is installed, some forms of overlaminate boost the life expectancy of a print by several years.
When it comes to large format graphics, lamination benefits installers as well, as it gives the total construction more dimensional stability during application. This makes it easier to install and remove—saving time and money, notes Jodi Sawyer, product manager, FLEXcon Corporation. “Many installers use masking tape to position large graphics and laminate protects the graphics during this process.”
Aside from protection, laminates are a cost-saving tool. “Instead of using expensive photo paper to get a professional, glossy print, you can use bond paper and protect it with a glossy overlaminate that not only makes the image look better, but provides extended protection and value,” observes Conrad.
Aesthetics also play a role in deciding to laminate. Different textures are used to add accents to a finished graphic. “In the past, laminating was always about imitating a gloss finish,” shares Martin Kugler, corporate communications manager, Hexis USA. Today, there is a surge of interest in matte finishes, as well as unique styles that mimic the look of carbon fiber or metallic flecks. The metallic look is big for PSPs targeting the RV market, shares Arlon’s Daize.
Laminates add cost and labor hours to a job, cautions Karla Witte, director of product development, INX Digital International Co. “PSPs must consider if they need to add another step in the process and if the extra cost is necessary.”
“We recommend using a laminate only when it’s called for. For example, when using aqueous inks or to increase the life of the graphic and protect against chemicals, abrasion, and graffiti,” adds Judy Bellah, public relations manager, Clear Focus Imaging, Inc.
Overlaminate FilmThere are a wide variety of overlaminate films to choose from, each with unique chemical compositions that impact performance and cost.
For durable outdoor graphics, a two-millimeter cast vinyl should do the trick, shares Dan Haan, GM, Advanced Greig Laminators, Inc. Polyester-based laminate films coated with thermally activated adhesives are a lower cost alternative than pressure-sensitive films, but won’t hold up as well, he warns.
Polyester-based films are outdoor durable for two years, but are not conformable, so they can’t be used on vehicle wraps. Polycarbonate-based films are even less conformable but are “tougher than PVC and offer better protection against tearing and chemicals,” notes FLEXcon’s Sawyer.
Polycarbonate-based laminates resonate with some PSPs because of a strong “cosmetic appeal,” observes Haan.
“It’s important for printers to understand that polyester and polycarbonate films, compared to vinyl, expand and contract at different rates when exposed to heat or cold. This causes shrinkage or piping. Polyester and polycarbonate are rigid films and should not be rolled up if laminated over PVC,” stresses Sawyer.
Indeed, one of the key considerations when pairing a laminating film with a base media is how the two behave when matched.
“It’s important to keep the overlaminate substrate the same or use a compatible material, otherwise the materials may shrink at different rates, and therefore curling or twisting and ultimately fighting each other,” recommends Reed Hecht, product manager, professional imaging, Epson.
Matching like to like—cast media with a cast overlaminate, or calendered with calendered—is essential. PSPs could manage by applying a cast laminate to a calendered film, but they should never put a calendered laminate over a cast film, warns Daize.
UV inks present laminating challenges as well. Because UV inks cure with low-surface energy, it’s difficult for laminates to adhere to them, explains Jerry Hill, VP, Drytac Corporation. The inks sit above the base media, creating a “tenting” effect that leaves a tiny airspace between the overlaminate and the media.
“UV inks are more challenging to adhere to than other inks, and more difficult to wet out,” seconds Mary Ann Kucera, product marketing manager, MACtac Graphic Products. “Poor wet out leads to a phenomenon called ‘silvering,’ which results from air entrapment between the laminate and UV ink.”
Whatever film is chosen, it’s important to let the ink dry completely before application. That “may take a minimum of 24 hours or more, depending on ink lay down,” cautions Kucera. Sawyer notes that 48 hours might be a safer window.
When in doubt, consult a dealer or vendor, advises Paul Roba, strategic sales technical manager, Avery Graphics. Most OEM material is well tested, but it makes sense to perform personal tests to ensure compatibility and performance, he adds.
Liquid LaminatesLiquid overlaminates can be applied to a range of applications, from high-end fine art reproductions to vehicle wraps, banners, and wall textiles.
DreamScape recently reformulated its liquid laminate to cover a broader range of digitally printed graphics created with a non-water sensitive ink. “It’s ideal for textured vinyl,” says Peter Spotto, worldwide sales manager, DreamScape.
“Liquid laminates are a good option when the graphics are installed over extreme curves or when you want maximum visibility through the film,” advises Clear Focus’ Bellah.
PSPs favor liquid laminates for the cost savings compared to film laminates. “A regular glossy, aqueous, or UV-based laminate can cost about two to four cents per square foot, whereas film may be 25 to 50 cents per square foot,” explains Hill. However the capital costs of liquid lamination are higher up front, as liquid laminators cost more than film laminators, he notes. But unlike films, some liquid laminates can be applied by hand, using a thick paint roller or spray painter as a tool.
While cost makes them an attractive alternative to films, liquid laminates don’t behave like film. Offering UV protection and abrasion resistance, they won’t transform a limp print to a rigid board.
For the fine art reproduction/giclŽe market, liquid laminates are the preferred coating solution. Here too, attention must be paid to compatibility, stresses Jim Manelski, president, BullDog Digital Imaging Products, Inc. For fine art printers using a water-resistant canvas and pigmented inks, a water-based laminate is ideal. A standard, “swellable” canvas requires a solvent coating because the ink sits on the surface of the canvas and washes away or bleeds when a water-based laminate is used.
Once applied, solvent and water-based liquid laminates are similar performance-wise, adds Manelski. The look of the print hinges more on the choice of canvas. Water-based coatings developed significantly over the past two years. “Prior formulations were acrylic and yellowed over time. Today, modern polymers prohibit yellowing, and they lack volatile organic compounds, which make them a ‘greener’ solution,” he adds.
Be wary of eco-friendly liquid laminates, cautions Terrence Crowley, president, Optima International, as many water-based coatings are produced with solvent-based resins, mitigating their green factor. When deciding on a potential liquid laminate for fine art use, be sure it features UV light absorbers and hindered amine light stabilizers, he adds.
On the LineA lot more than ink, media, and overlaminate goes into a graphic. PSPs, brands, and agency reputations are on the line. The final product must satisfy everyone for the entire life of the print.
The bottom line when it comes to durability is simple, says 3M’s Boxeth. "End users purchasing graphics expect them to perform. It’s their image and message. If that is tarnished, it’s not worth doing in the first place." Matching the job with the correct overlaminate is essential.
Jan2010, Digital Output