By Cassandra Balentine
Dye-sublimation (dye-sub) printing, using either transfer or direct methods, is a popular process for printing to certain textiles and rigid media. For textile printing, dye-sub involves turning ink into a gaseous state with the use of heat to infuse the fibers of the media.
With the increased demand for digital textile printing, the spotlight on dye-sub attracts new developments in terms of printing and finishing equipment, media selections, and ink.
This article looks at market trends associated with dye-sub ink, including new ink sets and formulation advancements that address efficiency and stability and how they benefit print service providers (PSPs). Further, we take a look at how the latest dye-sub inks are utilized for the creation of popular backlit applications.
Dye-Sub Ink Trends
The dye-sub process is known for its soft hand and brilliant output. However, there is always room for improvement. Tweaks in ink formulation and the development of new color options, like fluorescents and high-density blacks, enable higher quality, expanded gamut, and new application possibilities.
Ink manufacturers and their chemists continue to find new ways to spread innovation with the help of the latest technology. Matt Gusse, VP sales and marketing, Advanced Color Solutions, Inc., says a rebirth of optional colors, such as fluorescent/neon, spot colors like violet or orange, light blacks, and high-density black, seem to be making more of a push than in the past. “A decade ago, fluorescents were very tough to find. They were used in limited applications such as costumes, safety, and entertainment,” he recalls, adding that today, bright colors are requested more.
“Sublimation shops around the country and globe are requesting sample prints and information on how to obtain or hit these colors and what they have to purchase to do so. The requests result in the ink manufacturers delivering a quality, stable product.”
Michael Pender, president, Supply55, Inc., admits to a small but growing demand for neon dye-sub ink, noting that neon pink and yellow appear to be the most popular colors.
High-density black inks are another innovation. “The recent introduction of rich, high-density black inks plays an important role in production of apparel and signage products,” says Tim Check, product manager, professional imaging, Epson. Not only do they produce better blacks and rich tones; the increased contrast makes colors appear more vibrant.
Improvements in RIP software enable a broader range of dye-sub inks such as lighter shades of black—including light and light-light black—for better shadow and mid-tone detail; light cyan; and light magenta in six- and seven-color systems, explains Ed Michaels, product manager, dye-sub textiles, STS Inks. “Orange and green are also available for nine- and ten-color systems. Fluorescent inks are reemerging as spot and brighter colors integrated into eight-color systems producing vivid light greens and bright pinks,” he offers.
According to Jack Papaiacovou, VP/GM, Hilord Chemical Corporation, a six-color system is generally beneficial to achieving smooth transitions and high resolutions at the lower tone areas. “In the same fashion, the use of light black in the system would allow the generation of smooth transitions in the gray areas where pure black is required.”
Improvements in dye-sub ink dispersions and carriers also have a substantial impact on the stability, continuous jetting, and overall performance of dye-sub ink currently being used, says Michaels. “Particle size is now more uniform due in part to the sonic milling machines employed in the process. This has permitted new formulations to meet the demands of the printer manufacturers and the different printheads used,” he explains.
Marco Girola, marketing specialist, Kiian Digital, points out that in addition to trends such as wider color gamut, florescent, and more concentrated inks, there is increased attention on eco-friendly products in terms of inks and fabrics, but also a waterless process with lower energy consumption.
Advancement Benefits
With advanced inks, PSPs offering dye-sub applications benefit in a variety of ways, including improved productivity, a wider color gamut, and efficiency. High-density ink options help improve productivity.
Tony Cox, business manager, Sun Chemical Corporation, suggests that the new generation of dye-sub inkjet inks give brighter and stronger colors complemented by black inks with a higher density. “These features can allow the printer to use shorter sublimation times, which increase productivity. They can also be used on reduced weight transfer papers, which offer significant cost savings.”
Lily Hunter, product manager, textiles and consumables, Roland DGA Corporation, adds that because high-density dye-sub inks have less water in their formulations, they dry quickly on the transfer paper to speed up workflow.
Rob Almstrom, founder, American Print Consultants LLC, agrees, adding that high-density inks facilitate faster printing by reducing the amount of liquid being deposited on the carrier, reducing ink drying time, and preventing issues with stamping and artifacts caused during material take up.
He says the inks can also decrease the amount of cockling in the paper during printing, reducing the need for printer maintenance and lowering rework rates. “The same properties can also help reduce manufacturing costs, allowing lighter weight and less expensive papers to be utilized more effectively.”
The availability of fluorescents, spot colors, and light inks expand the print gamut, leading to different applications.
“Florescent sublimation inks allow for brighter, more eye-catching color,” says Almstrom. “While at some point the demand for these products is likely to segue into temporary soft signage, they are currently meeting the growing demand for textile products in the apparel and furnishings market,” he states.
“As dye-sub is expanding more into the soft signage area, there is a greater need for a larger color gamut and more vibrant and vivid output,” comments Papaiacovou. Fluorescent dye-sub inks provide a neon look at the visible spectrum and fluorescent at the lower wavelengths.
Michaels believes that a more varied ink palate allows users to expand into other markets once only served by eco-solvent or pigment-based printing systems. He says dye-sub has expanded into grand format banners and backlit display products and that better and darker black dye-sub inks have helped the transition from solvent.
Tommy Martin, product manager, textile and apparel business development and marketing, Mimaki USA, Inc., says expanded ink sets augment the dye-sub color gamut, enabling an end product with a more photorealistic look. However, he admits that these expanded colors have a specific purpose that not every customer needs. For example, if a customer is producing active sportswear and the like, they will be looking at florescent colors and possibly spot colors, while someone producing photo throw blankets might need light colors to help reproduce an image more like the original photo when transferred.
Advancements also help to improve the dye-sub process in terms of efficiency and lower costs. “This is partly due to the fact that technologies in both equipment and consumables have become more refined as a result of the rapidly growing demand for these products. Also spurred by this growth are innovations such as inks with higher dye loads and new pigments for florescent and other special effects,” explains Almstrom.
The characteristics of improved ink for transfer printing include fast drying on paper, higher prismatic color performance, and better ink jetting performance—specific to the type of printhead, suggests Martin. “Printhead specific jetting performance is important to the life of the printhead. Printing with inks that are optimized to the specific type of printhead means fewer maintenance issues, less downtime for service, and fewer printhead replacements. An analogy would be trying to run diesel gas in a high-performance gasoline car engine, it just causes issues,” he warns.
Application Focus
Regardless of ink trends, the digital dye-sub process is well suited for particular applications, but not a fit for others.
Apparel, furnishings, and soft signage applications are among those primarily targeted by dye-sub. However, the process is not limited to textiles and works on rigid materials as well. The latest ink sets follow the path of traditional application uses and provide new possibilities.
Gusse suggests the digital dye-sub process is appropriate wherever the need for eye-catching colors exists.
Check says applications that benefit most from high-density black inks include fashion apparel, because the increased contrast with a bolder black results in colors appearing more vibrant; sports apparel, since a rich black produces sports jerseys that are easier to see and identify team logos, numbers, and names; and backlit signage, because with darker blacks, less light is transmitted through the fabrics, resulting in a backlit graphic that has more vibrancy and color pop.
Expanded gamut offerings also allow for better fine art and photographic quality output with dye-sub processes. “When properly profiled and used with your RIP software, adding light blacks or even light-light blacks create flesh tones and photo-realistic imagery with results once thought unachievable with dye-sub,” adds Gusse.
Michaels says that the availability of 104-inch dye-sub printers paired with 125-inch calendar presses allows for the production of grand format signs and banners as well as photographic quality backdrop scenery for theatrical production and trade shows.
While a variety of applications are suited to digital dye-sub, it is important to remember that the process is limited in terms of material capability and durability.
Hunter adds that you still need to use 100 percent polyester fabrics for dye-sub applications. “Different types of ink work best with different types of fabrics and the unique chemistry of dye-sub inks requires transfer to 100 percent polyester materials for optimum results.”
Dye-sub inks are not ideal for dark garments or fabric. “A dye-sub substrate starts out as white. The background color is created in the design. You cannot print on dark substrates and have the dye-sub image visible,” explains Michaels.
Paul Leh, VP, Rainbow Pigment Co., Ltd., comments that digital dye-sub inks are not ideally suited for outdoor advertisements, due to poor light resistance that may cause the color to fade.
Martin agrees, noting that paper transfer is not best for long-term outdoor applications such as flags, furniture, outdoor banners, or more durable fabric needs. “These applications should be direct to fabric,” he states.
“Sublimation is not ideal for outdoor use due to the outgassing, dye migration, and UV fade,” adds David Gross, president, Condé Systems, Inc. “In the coming years, I think significant progress will be made to provide a solid three-plus year product. This will be done by improving the sublimation inks and coating used on substrates. Polyester fabric will also benefit from these changes,” he says.
Almstrom believes that while high-density inks are designed to facilitate high-speed printing and can serve to increase viscosity, these properties make the dyes ill-suited for the small format and specialty market where low cost and low volume is more the general rule.
He suggests that while these inks will generally work with most types of polyester textiles, there can be less than favorable results in certain situations. “An example of this can be found in the fact that high-density inks can be out performed by wetter, more traditional inks in areas such as penetration on fabrics where double-sided print is the goal.”
“Some ink manufacturers claim to be able to work with different types of inks. My experience is that some have a primary and secondary purpose,” says Martin. The primary is the purpose for which the inks were originally developed, and the second is an application that might work for a specific application, according to Martin. That secondary application was developed to fill a need and is considered a best success option without developing another ink from scratch. It’s important to also consider fabric, processing, and final use when selecting an ink/process, as it’s not only the ink that determines success.
Juan Kim, CEO, Valloy Incorporation, believes that digital dye-sub technology is mature enough for both direct and indirect applications. “So, there will be minor variations like fluorescent and spot colors or low temperature sublimation. However, low temperature sublimation requires shorter chains of polymer, which makes washing/UV durability poorer so it is only applicable for direct sublimation of short-term soft signage.”
“If the application is suitable for sublimation, there should be a formula to obtain the desired results. Now the ingredients for the formula may vary, that’s why it’s great to have a variety of choices from manufacturers,” states Gusse. He explains that putting together the right package of equipment, ink, paper, substrate, software, and information to make each buy successful is the job of the dealer/application consultant and their respected channel. “The goal should be zero or minimal after the purchase research on the buyer’s part to print their product to the highest quality standards.”
Dye-Sub Inks and Backlit
Applications
The dye-sub process is known to be conducive to items such as sportswear apparel and indoor soft signage displays, including backlit applications. New ink sets offer richer colors that further the attractiveness of the dye-sub process for backlit graphics.
“High-density black ink will produce a better backlit print with deep blacks and vibrant colors,” offers Check. “Using optimal settings in the color management RIP software specific for backlit printing with high-density black inks, the software will ensure that a sufficient amount of ink is printed to achieve a rich black on the finished fabric.”
In general, the color gamut for dyes exceeds that of pigment inks due to the weight of the colorants used in the manufacturing of these products, says Almstrom. “The same properties allow light to more easily be transmitted through the material allowing for vivid, saturated color with minimal decrease in luminosity.”
Hunter explains that for backlit applications, a heavy layer of dye-sub ink is needed so the graphics don’t look washed out when backlit. “Typically, you will need to use at least two layers or a double strike of inks, just as you would for eco-solvent backlit signs.”
Gross says that a dye-sub, backlit LED light box has a “unique beauty” that printable backlit film lacks.
In addition to ink development, the materials used for producing backlit applications with digital dye-sub are critical.
“For backlit and LED frames, it’s really the fabric that is key to a great presentation,” suggests Gross.
For these applications, Michaels notes that the material used reflects how well the graphics will image with the dye-sub ink. “Ideally, you want to produce as dense an image as possible without burning the fabric. New lower temperature dyes and rich, dense black dye-sub inks can produce highly saturated images needed for backlit applications. It does not make much of a difference printing directly on the fabric or using the transfer method. When printing directly on the fabric, it is moved to a heat press for fixation unless the printer has a fixation system as part of the printer.”
Check suggests there are pros and cons of both direct print and transfer printing of backlit applications. “With direct printing, the ink is applied directly to the fabric fibers, which can color both the front and back of the fabric. This has the benefit of slightly greater black saturation over transfer printing,” he offers. “However, the direct print fabrics require a pretreatment to minimize the amount of ink bleeding, which can cause a loss of image sharpness.”
He explains that transfer printing doesn’t require pretreated fabrics, and the quality typically has better retention of details and sharpness. “During the heat transfer process, the inks color the front and side of the fabric fibers with the backside remaining uncolored. This results in slightly more vibrant colors, but slightly less black saturation than direct printing.”
New Ink, New Applications
As digital dye-sub inks continue to advance and color gamut expands, new applications benefit from its vibrant output. IPM
Nov2016, Industrial Print Magazine
