Digital inkjet manufacturers make great efforts to introduce white ink to the digital production process. A range of applications are prevalent. Of popular note are window graphics applied both indoors and outdoors. The clear vinyl or film is an ideal base to showcase the capabilities of white ink.

White-Enabled Workhorses

“White ink is more than a unique specialty color,” shares Julie Gederos, product manager, Roland DGA Corporation. “It’s an entry point into new applications. It allows a shop to broaden its reach into new markets, for better overall growth and profitability.”

Though some print engines treat white ink as an add-on or option, for the digital print service supplier, having the capability is anything but optional, according to Steve Cutler, marketing product manager, mid-range inkjet, graphic systems division, Fujifilm North America Corporation. “You need to have it,” he asserts.

With white ink enabled print engines, Cutler suggests not only considering the ink, which must offer exceptional opacity, but also how the printer applies it—the fewer the passes, the better.

John Kaiser, product marketing manager, inkjet inks, Fujifilm concurs, “the biggest difference we see with white ink is the opacity. The more white pigments you have, the better the result. You’re going to have fewer passes needed on clear substrates.”

“The white pigment is a heavy substance, which tends to settle out a lot, and many printers don’t have a recirculation system. That’s a key consideration and a distinction found between a printer that’s a couple hundred thousand dollars and a printer that’s $50,000,” he continues.

Applications & Opportunities

Some of the most prevalent applications for white ink include printing on dark or colorful substrates, in backlit, and in graphics projects that require two-sided printing.

But Cutler suggests emerging applications are piquing the curiosity of graphics creators—textured printing, for example. “We have a trade show graphic that we print a lot. It’s a picture of a lizard, and when you brush your hand over it, you get the sensation of feeling the scales. People ask, ‘How did you do that?’ Well, we jet white ink between the color layers, so it builds up the image.”

For many print service suppliers, there doesn’t have to be a learning curve, or concerted efforts to break into new types of print applications, unless that’s the goal.

“Typically, a lot of these print service providers (PSPs) are already doing these applications, but another way. If you look at screenprinters, for example, they printed white backlit before. Even when they first adopted digital equipment, they didn’t have the ability to print white, so they’d screen the white on the substrate,” recalls Kaiser.

That was the case for UK-based Image Factory, which installed a Hewlett-Packard (HP) Scitex 7600 during 2012. The print provider installed an HP Scitex FB7500 the prior year. Tim Boore, head of digital technologies, Image Factory, cited the solution’s optional White Ink Kit—with HP FB225 White Scitex Ink—as enabling the move away from screenprinting.

HP offers a number of digital printing solutions that feature white ink, including the HP Scitex FB500, FB700, and FB7600. “For the HP Scitex FB7600 we use UV-curable ink technology, which allows us to print on many types of plastics as well as metallic,” explains Eyal Duzy, strategic marketing product manager, Scitex, HP. Window graphics are popular applications for this technology, he notes, and says that knockout printing is generating great results for those types of print jobs.

Knockout printing, according to Duzy, requires the layering of CMYK, white, and black-only inks—five layers total—on clear substrates to create one image on one side and another on the other.

In order to do this well ink chemistry matters greatly. “When you’re printing two, three, or five layers of ink it must feature good adhesion and high flexibility; otherwise, it will crack and break, and the image won’t look good.”

The introduction of white ink creates both opportunity and challenges. When evaluating the potential for either, it’s important to start at the beginning by asking, “What can we do with white ink?” ponders Rob Stone, director of operations, Contra Vision Ltd.

Stone offers an example of an interior application that calls for white ink. A clear, perforated media applied to the inside of a window allows for viewing from the inside and outside. It’s protected from the elements and zoning issues aren’t a problem. An opaque white ink is necessary.

“Used in conjunction with Contra Vision Performance clear perforated vinyl, PSPs produce inside application see-through graphics, which are protected from vandalism, rain water, and street dirt. They are used where outside application may not be possible because of access problems, planning issues, or a coating on the glass. The clear perforated vinyl is printed with the reverse-reading image, and then backed up with a white and then a black ink layer,” expounds Stone.

Tim J. Boxeth, business manager, 3M Commercial Graphics, says that 3M Scotchcal Clear View Graphic Film IJ8150 is an option for glass-, acrylic-, or polycarbonate-situated graphics that may call for white ink. It is lauded by 3M for its simulation of perforated window film, minus the holes that may collect water and dirt, and its compatibility with latex, solvent, and UV-curable print systems.

Rob Moore, national account manager, Arlon Graphics, LLC, says the company’s best-selling clear media is its DPF 6000RP Clear, a 2-mil cast film. “One of the more common issues with printing white ink onto clear media has to do with the brittleness of the white ink, and the amount of stretch that is common with most clear cast vinyl,” confides Moore.

“When applying, it is common for the ink to crack. One way to overcome this issue is to apply a laminate that adds stability to the vinyl and protects the ink from cracking. The laminate also makes it less susceptible to abrasion.”

Lintec of America, Inc.’s Wincos UV product line includes printable optically clear window films that are non-PVC based. “Recent developments in UV LED and latex printing allow some traditional label printers to acquire inkjet technology for their label production as well. While we haven’t seen large volumes in this area we expect it to become a complementary technology with traditional flexographic printing,” explains Jim Halloran, VP sales and marketing, Lintec.

MACtac Graphic Products offers the IMAGin B-free line of window films, equipped with air egress media for dry application to windows. For those requesting a more eco-friendly clear gloss media, MACtac IMAGin Verde VM3209R is a topcoated polyester face film suitable for printing with UV ink.

With layers of white and black and CMYK, a PSP enables a retailer to create a graphic-rich partition with an image on one side, a different image on the other side, and still allow for light and vision to pass through it, according to Stone.

The same principles and practices are also applied to non-retail applications—in offices, for example. “There are ‘green’ initiatives that now require natural light to pass through buildings,” explains Stone. “The people who work in the office don’t like glass partitions, because everyone can see whatever you’re doing, what you’re working on. Printing on those partitions would allow for some level of privacy.”