Primer: A Guide to Wide-Format Printing Inks

Wide-format printing inks have seen innovations over the last several years, from expanded and more vibrant color gamut to quick and instant-dry properties. Whether it’s eco-solvent, aqueous, resin/latex, or UV, there’s the correct ink for any use, with some ink platforms rising above others for specific applications. Print service providers (PSPs) need to understand the advantages and limitations of each to ensure they choose the right technology for the products they’re producing. 

Solvent Inks 

Eco-solvent inks, also known as solvent inks, are widely used worldwide, says Timothy Mitchell, senior product development director at S-One Holdings. He labels them as very reliable and successful with a good color gamut.  

They work well on most PSPs' materials, including adhesive vinyl and banners. Adam Shafran, president at STS Inks, adds that solvent inks are ideal for outdoor applications due to their durability and water resistance. However, he says graphics may not print as vibrantly as other ink types. 

While some solvent inks can have an odor if not adequately ventilated, refinements in the ink technology make it much less hazardous, with no issues regarding nickel, HAPs (hazardous air pollutants), or harmful VOCs (volatile organic compounds), Mitchell says. “Almost all modern eco-solvent, at this point, is GREENGUARD certified, so it meets traditional industry expectations for operator safety and installations.” 

One qualm with solvent inks is that they don’t like paper-based products, like paper-based wallcoverings or photo paper. However, with a special coating, solvent inks become compatible with paper. Mitchell notes they also don’t do well with fabrics unless they are heavily coated.  If laminating is necessary, there’s an outgas period, so factoring that time in is essential. It’s also not the most scratch-resistant of the ink bunch, falling behind resin/latex and UV.  

Epson, Roland, and Mimaki are three big players in the eco-solvent category, using Piezo print heads, which last longer than thermal print heads.  

Best uses: Outdoor signage, adhesive vinyl, vehicle wraps, banners, and most films. 

Aqueous Inks 

Aqueous inks have been in the industry for a long time and are most suitable for technical indoor applications, including fine art and photo printing, reprographics, and architectural blueprints. They do offer some limited outdoor applications, Mitchell says, with the big aqueous players like Epson, HP, and Canon offering water-resistant ink, as well as an expanded color gamut.  

Most aqueous printers do not use heaters. The coating on the media holds the ink in place, which is nearly dry when it comes out. However, it does need careful handling to fully dry unless the media has a special instant-dry coating.  

Speaking of coatings, “All aqueous base is coated,” Mitchell says. “So, the coating is key. The quality of the coating is important. ... Then, you pair it up with your aqueous printer and get perfect results. Coatings can degrade over time. Aqueous-coated material costs more; good coatings cost more; consistent coatings cost more. Anything you do with an aqueous printer, you'll have a higher cost for ink and materials because the materials must be specially designed so that the aqueous lands on the coating, holds steady, and looks great. Then it air dries.” 

Shafran says these inks are environmentally friendly and have low odors but are less durable than solvent or UV inks.  

Best uses: Fine art reproduction, photography, blueprints, architectural printing, and indoor posters. 

Resin/Latex Inks 

Resin and latex inks are also in the aqueous ink family, but they serve their own purpose. One is that they can handle indoor and outdoor applications without issues on an extensive media selection. Due to a synthetic resin copolymer in the ink, when it’s heated, it activates and encapsulates, making it durable and flexible for the outdoors, Mitchell explains.  

Mitchell and Shafran also note the environmental friendliness of these inks — Green Guard and Forest Stewardship Council certified, meaning no VOCs or HAPs.  

“Now, Resin and latex are effectively the same thing,” Mitchell explains. “Latex is a synthetic resin copolymer, so it's resin. Latex is a brand name that HP invented. Nobody else was doing it at the time. They didn't want it associated with older resin-type technologies like ribbons, so they called it latex. It's still a resin printer.” 

Some latex printers use thermal print heads, which need replacing more often than Piezo print heads. A Piezo print head, which Epson and Roland use for their resin/latex printers, can last several years, whereas a thermal print head could need replacing every six months, depending on how much it’s used, Mitchell says. “It's about $180 a pop, which isn't a lot, but it's something you must consider,” he adds.  

Additionally, he says there’s a color shift with thermal print heads. HP printers have technology to remedy the issue, but Mitchell says it’s still a “moving target.” That said, latex is seen as a universal option alongside UV ink. 

Best uses: Indoor and outdoor signage, fabric, vehicle wraps, and wallcoverings. 

UV Inks 

UV inks, focusing on LED UV, also work with a wide range of media at a good price point. It’s “quick drying and suitable for high-speed printing,” Shafran says. Because there’s little to no heat, UV inks work well for heat-sensitive materials like Coroplast, thin styrene, and thin polypropylene, Mitchell notes, with Coroplast being a dominant player for this ink platform. It offers excellent scratch and scuff resistance and color consistency, making it great for the decor market.  

UV lamps cure the ink as it passes through the printer rather than going through an additional curing zone. This allows for high-speed printing, and Mitchell says it’s likely the most widely used commercial technology. Everyone from DigiTech, Fluid Color, Mimaki, CET Color, and Epson to Durst, Vanguard, EFI, and more has skin in the UV game, offering high-quality printers, he adds. 

PSPs need to weigh two considerations when exploring UV inks: the elasticity and slight odor. UV inks aren’t as flexible as eco-solvents or resins. While there are some elastic UV formulations, Mitchell says few people use them for vehicle wraps other than on the side of a truck or bus.  

“As the ink gamut continues to expand, the quality of ink elasticity, effectiveness, jet ability, it's just going to become a bigger and bigger thing because there's just a huge weight of all of these companies developing for it, and it's a real proven technology, and it has an established base at this point,” Mitchell argues. 

Best uses: Signage, clear window film, fabric, packaging, wallcoverings, and promotional products. 

UVgel inks, while in the UV category, offer something a little different. Mitchell describes the gel, a Canon product, as a concentrated UV “ink,” whereas the PSP doesn’t have to use as much.  

The gel is heated in the print head, turns to a liquid, then drops on the media, turning it back into a gel, and then it’s cured. Mitchell says this technology offers opaque white ink, Piezo print heads, excellent scratch and scuff resistance, and better elasticity than traditional UV ink. “It does everything UV can do,” he adds. “In some cases, it does some of it better.” 

Fabric is not one of those cases. It’s actually where UVgel struggles a little. “Don't know why,” Mitchell says. “UVgel seems to like no treatment like any of the treatments made for solvent, UV, or other latex. It doesn't like treatment. It almost wants things just base cloth.” 

Best uses: Wallcoverings, banners, and production display on canvas (hotel and restaurant art). 

For a PSP’s sign and display purposes, Mitchell ranks the different inks, with solvent taking the No. 1 spot, followed closely by UV inks, and then latex. Aqueous stands on its own because it’s used for such technical and specific print jobs. While it’s easy to only focus on cost or speed when deciding on the right ink platform for a job or business, several factors should play a role.  

“Choosing the right ink type depends on the specific requirements of the project, including the desired application, substrate, and longevity of the print,” Shafran adds. “Each ink type has its unique advantages, and understanding these differences helps make informed decisions for various printing applications."