Maintaining media profiles can be challenging. This holds true for most substrates, whether it is color-based or clear. This article looks at how to print onto clear vinyl and film to ensure vibrant, colorful window graphics—indoors and out. The elimination of white point in both the media and intended surface—as both are see through—create an a-typical print situation.
A faint or oversaturated print is a possibility if color density isn’t properly monitored. There are various tips and tricks to master color density on each type—perforated, unperforated, static cling—of clear substrate, whether it involves increasing color density or utilizing a layer of white ink. Lastly, working closely with media and print manufacturers to create an accurate color profile is an important consideration.
Open Your Eyes
Correct color density ensures accurate, high-quality window graphics. If not addressed prior to the final print, the outcome is less than satisfactory. “Over time prints that are not produced correctly tend to fail to deliver their intended message,” cautions Matt Devlin, VP business development, Natural AdCampaign Ltd.
Printing to clear media presents challenges that wouldn’t necessarily appear when printing to solid color vinyl or film.
The largest difference between clear and solid color media is the white point. “The problem with profiling a clear material, particularly when that clear substrate is applied to windows, is that there is no white point to read,” shares Tom Hauenstein, account specialist, LexJet Corporation.
“Without white backing, much of the ambient light travels through the film rather than be reflected back to the intended viewer’s eye. This can result in colors that appear faded or washed out,” agrees Michael Prewitt, technical development manager for inkjet media, Neschen Americas.
Daniela Kasseckert, marketing manager, ASLAN Schwarz GmbH & Co. KG, cites the appearance of the desired image is generally darker on glass decoration films because they are grey. “On the other hand, the colors appear paler because of the light coming from behind,” she continues.
Lawrence Delesio, business development manager, DAF Products Inc., provides a physical example to better illustrate the difference. He suggests thinking of clear material being projected like an old three millimeter slide or a transparency projection, but on a much larger scale.
Designers need to be notified when working with print providers and clear media. According to Nate Goodman, product manager, Drytac Corporation, traditional media does not require as sharp of a line, because the viewer won’t look through the print. However, when printing to clear vinyl and film, the lines of the graphics must be considered—they should be distinct to the viewer.
The aesthetic a customer has in mind is another factor. Depending on the color density, the look and feel of the graphic changes. “With clear films a translucent or more opaque look can be achieved,” explains Robert Rundle, viscom market manager, Ritrama.
The final environment the window graphic is placed in should also be considered. “Print providers should understand graphic placement and lighting, and how these factors may impact the opacity required to make the graphics visible and vibrant,” adds Dennis Brunnett, product manager, product branding business team, FLEXcon.
Visible Tips and Tricks
Clear substrates used in window applications involve a desired opacity or translucency. Ink density and/or printing with a pass of white ink—if the capability is available—are two helpful solutions.
Commonly with clear media and film, ink densities are increased to compensate for the lack of white. However, print providers must manage the process.
“Depending on the print method, printing several layers can lead to ink adhesion issues, which can be dealt with, for example, by using digital printers that provide superior ink receptivity,” recommends Brunnett.
Many wide format digital printers have the capability to print white ink in multiple layers, which is becoming popular feature. This offering is ideal for those commonly printing to clear media used in window applications.
The layering technique is most influential on the process. “If you have a printer with these capabilities you can have it print a white layer behind the colored layer and this will bring back a lot of the pop that is missing from color-only graphics printed on clear films,” says Mark A. Elvester, senior technologist – technical service, overlaminates and UV inkjet inks, 3M Commercial Graphics.
Judy Bellah, public relations manager, Clear Focus Imaging, Inc., cautions however, that this isn’t a surefire solution, depending on the ink quality and printheads, there is a difference in output. “Although there are a number of printers on the market with white ink capability, the white coat must be sufficiently opaque to prevent the colors from looking muddy after the black coat is applied.”
It also depends on the printer/ink type. “A solvent printer is more transparent in the lighter colors, so a flood coat of white is sometimes needed,” explains Jason Yard, marketing manager, MACtac Distributor Products.
When printing with UV inks, special attention should be given to the amount of ink used, as ink anchorage decreases heavier laydowns during the post-cure process, advises Brunnett.
Ink density issues vary depending on the media—cast and calendered vinyl, perforated and unperforated, or static cling media without adhesive backing. “Each type of media receives the ink a bit differently,” adds Rob Moore, digital national accounts manager, Arlon Graphics, LLC.
“Another consideration to keep in mind when printing clear substrates—at least those with an adhesive—is the color of the adhesive. While some adhesives are clear, others have a yellow or brown tint to them, and those tints can alter the color of the finished printed graphics,” recommends Brunnett.
In all cases, when printing to a clear media, ink densities are greater, so it takes longer for the ink to dry. It is also important to point out that a graphic is only as good as the media printed to it. According to Kasseckert, the quality of the material will have an impact on the print, as the coating will need to accept the ink properly.
All of this exploratory work should be executed prior to a full print run. “I always recommend printing a small test of the graphic with the media before beginning the full production run of the graphics,” explains Joey Heiob, regional technical specialist, Avery Dennison Graphics Solutions.