Determining the Best Path for Digitally Printing Fabric
The wide-format industry continues to see advancements in digital equipment to meet versatile applications and markets. For soft signage and fabric applications, this has meant the replacement of screen and other analog print methods with processes such as direct-to-fabric and dye-sublimation (dye-sub) transfer. But which technologies and materials are the best for your in-plant? As with adding any new equipment or service, the answer will ultimately depend on the applications that fit your customers’ needs and end uses.
Fabric’s Benefits and Processes
Utilizing fabric for signage applications has several benefits. While it’s much easier to transport than vinyl and rigid substrates, it can also be more sustainable. For example, with silicone edge graphics (SEGs) — where silicone strips are sewn or pressed onto the graphic’s edges with an adhesive, allowing it to be placed and held in metal framing — the graphics are easily interchangeable. Additionally, notes Michael Sanders, director of printable textiles & finishing technology at TVF, “The polyesters are recyclable, and they will break down. It’s not like vinyl that never breaks down in landfills.”
For those considering soft signage or other applications, it’s important to understand the processes for printing fabrics and their respective advantages.
“Fabrics can be printed directly with dye-sublimation, pigment, UV, and eco-solvent inks,” says Lily Hunter, senior product manager at Roland DGA. “If you’re using dye-sublimation or pigment inks, there’s usually a second process to fix the inks onto the fabrics. In these instances, heat is used to set the inks; [the] dwell time and temperature will vary.”
In the dye-sub transfer process, an image is printed onto coated paper, which is then applied to the fabric using a heat press or calendar.
“When you transfer the dyes, they go from a solid form on the paper to a gas form, [then a] solid form back into the fabric,” explains Victoria Nelson Harris, senior textile segment specialist at Mimaki U.S.A.
Direct vs. Indirect
While both direct-to-fabric and dye-sub transfer require a dry heat fixation post-process, Harris notes with direct-to-fabric printing, “you can lay a lot more ink down on the fabric [allowing you to] get better ink density and better ink penetration through the textile.”
For these reasons, direct-to-fabric is ideal for applications such as SEG frontlit and backlit displays, where light needs to be transmitted clearly and through the media without any shadowing. This ink penetration is also important, Harris says, for flags or banners that are viewed from both sides.
However, it is important to note direct-to-fabric printing requires fabrics to be pre-coated, although Harris notes UV inks can print on either coated or uncoated textiles.
“UV inks can be printed onto cotton or polyester fabrics. The inks are cured onto the surface of the fabric and are popularly used for backlits, SEGs, and various other applications,” adds Hunter. “Eco-solvent inks require that fabrics have a coating for ink receptivity, and are used for canvas, backlit signs, and more.”
By eliminating the cost of transfer paper and additional labor, direct-to-fabric can also be advantageous from a process workflow standpoint.
“For creating applications for the direct-to-fabric solution, it’s better for businesses ... to select a few fabrics and to utilize them consistently on a regular basis,” says Harris. “It makes for a much easier workflow because you can dial in your ink limits and then once you dial that in, you really can control your ink cost and [are] able to have a predictable business model.”
While direct-to-fabric presents many benefits, there are some instances where dye-sub transfer is a better option. For example, Harris says, if you’re producing graphics that will be seen up-close at eye level and require small details, dye-sub transfer achieves the best quality.
“With dye-sub transfer, you do get that really excellent high image quality and details, and very bright gamut of color,” she says.
“Dye-sublimation has been popular for various soft signage applications, such as trade show graphics,” adds Hunter. “The colors bloom as the inks dye the polyester fibers during the sublimation process. The benefits of this technology are brilliant colors, wash durability, and rub resistance. If you want to be able to wash the graphics and reuse them, this is the way to go.”
This durability is especially beneficial for shipping and transporting signage to trade shows and events.
“When you take a look at the soft signage with UV inks, it’s not as durable,” points out Harris. “You wouldn’t want to wash [it] and you wouldn’t want to fold it up; it’s more prone to cracking and scrunching in transport.”
However, while direct-to-fabric printers may include a built-in calendar/heat press, as Hunter notes for dye-sub transfer, shops will need to learn how to use the calendar, which due to its heat output, will need to be in a separate room from the printer.
In addition to technologies, shops will need to consider fabric choices, which have also evolved. “The advancements of the polyesters that are available right now in the market is unbelievable,” says Harris, noting characteristics such as wrinkle resistance and excellent light-transmitting qualities.
Echoing these sentiments, Hunter shares the availability of “polyester fabric that is coated on one side for use with eco-solvent inks or UV inks, while the uncoated side can be used for dye-sublimation. These types of media are great for indoor soft signage and backlit applications.”
When it comes to fabric construction for wide-format, Sanders says warp knits — not wovens — are the way to go.
“Wovens don’t have the dimensional stability. Let’s say you put up a big banner in a park; if it gets cut, it’s going to rip right across the fill line, and your banner is going to be ruined,” he says. “You never want to have an outdoor banner that’s going to be a woven because it’s not going to hold up.”
A graphic’s ultimate placement is also a factor in the technology and materials used, as outdoor graphics have to contend with the elements.
“When it goes outdoors, what you’re really worrying about is that you’re not going to get any migration of the color,” says Sanders. “Especially with mist and fog, it gets damp, and then all of a sudden, you get the heat of the morning coming. If there’s any color that’s not set on the fabric, it’s going to want to migrate and bleed. You need to make sure that the fabric is something that will take the color, but again make it so it holds it.”
For workflow purposes, Sanders adds that businesses typically have two or three options that are used for 80% of their jobs, which helps save money in purchasing more of one fabric versus smaller amounts of several. “[Shops usually want a] backlit, frontlit, a blockout, a flag, and then — depending on your customers and what you do — maybe one or two specialty fabrics.”
Along with printing equipment, ink technologies, and media, digital fabric printing entails a finishing process, such as cutting and sewing. As with any decision and investment, tapping into this niche means considering your current/planned offerings, evaluating your technology, and working with vendors on determining the right path forward.
“First, determine what the majority of your applications are and decide if your current printer/ink set is best, or if you need to invest in alternatives,” advises Hunter. “For example, if you’re doing a lot of trade show signage, flags, and table coverings, you will be limited if your primary tool is an eco-solvent printer. Having a dye-sublimation printer and calendar would be a good solution. If you’re doing a lot of canvas, backlits, and wall graphics, then UV printers or eco-solvent printers will work great.”
Whichever is the right path for your business, soft signage can be a viable opportunity, especially if you’re already offering wide-format.
“If shops are doing other signage applications, they can easily move into soft signage because it’s within their existing market; it’s an easy adaptation for them,” says Harris. “They can offer a new product and more variety.”