By Cassandra Balentine
Digital dye-sublimation (dye-sub) printing is continually adopted as the demand for customization rises. There are two digital dye-sub printing methods—transfer and direct.
Direct dye-sub printing involves sublimating ink directly to a textile. This process eliminates the need for transfer paper but requires pretreated fabrics. Printed fabrics are then run through a heat press or calendar to bond the ink to the fabric.
In transfer dye-sub printing, graphics are first printed to transfer paper. When the transfer paper makes contact with the fabric or substrate in a heat press, the paper releases the ink onto the fabric or material. The process supports a wide range of textiles.
While dye-sub transfer and direct processes commonly run on separate printers, “hybrid” or “multifunction” dye-sub devices present users with the opportunity to utilize both technologies on one piece of hardware. This is possible through machines that either support dual ink sets or one ink for both processes.
Hybrid models offer versatility with the ability to print directly to popular soft signage textiles that require heavy ink saturation as well as support transfer paper for apparel, décor, and rigid applications.
For sign and display graphics, particularly backlit signage, direct print holds up well. “In some applications, the greater ink penetration of a direct print can help with show through to the back side of the fabric,” explains Simon Daplyn, product and marketing manager, Sun Chemical.
Other applications are well suited for the dye-sub transfer process, says Mike Syverson, textile manager, North America, Durst Image Technology US. These include apparel, four-way stretch fabrics, piecemeal applications—blankets or rigid sublimation panels—and fabrics that may not be available with direct dye-sub pretreatments on them.
Above: HP offers a multifunction dye-sub printer in the HP STITCH S Printer Series, ideal for creating textiles for the home décor space.
A key advantage of hybrid printers is versatility. The ability to print to a range of textiles and/or papers with one machine enables print providers to offer expansive products with a single device.
“The main benefit for clients is owning one printing system that is sophisticated enough to serve two purposes,” states Randy Peters, president/CEO, The Mosaica Group.
Deborah Hutcheson, director of strategic business development and distribution, Agfa, adds flexibility as an advantage. “A printer that offers both direct print and transfer capability gives print service providers (PSPs) the flexibility to address a variety of applications with a single printer ensuring a higher level of utilization. This is especially important to PSPs new to the soft signage/digital textile world,” she offers.
Hybrid printers allow for expanded production possibilities. “The ability to print direct to fabric or use intermediate transfer paper can increase the range of substrates and applications open to the printer,” notes Daplyn.
A hybrid process has the ability to eliminate the transfer step by using an ink that will print directly to the final fabric and reduces time and money spent as well as providing environmental advantages by eliminating paper waste. “These advantages can increase your effectiveness as a print provider and increase your speed to market,” shares Scott Donovan, Americas sales manager, Artistri Digital Inks, DuPont.
Mark Goodearl, senior ink product manager, EFI, adds that with hybrid textile printers, businesses can quickly produce a broader range of fabric jobs with dye-sub inks, featuring bright colors and strong penetration when printing direct to fabric on standard synthetic soft signage media. However, when the final graphic is a substrate not suited for direct printing, customers can easily switch to a transfer paper media without having to purge and switch out ink sets. “That can create a significant time and expense savings for customers,” he adds.
Running dual ink sets with textile pigments and dye-sub inks brings fabric and product versatility. “Textile pigments feature great color fastness and wide color gamut, making them ideal for interior décor and apparel applications,” says Victoria Nelson Harris, senior textile segment specialist, Mimaki USA, Inc. “Dye-sub inks are excellent for soft signage, sportswear, fashion, and home décor. Textile pigment inks, direct and transfer sublimation inks all have the same post process using a calendar heat press, so only one additional unit with the printer is needed for investing,” she continues.
Syverson points out that devices featuring inline sublimation are beneficial as they often eliminate the need for a standalone heat press, reducing footprint, power consumption, and operational expenses.
While there are many benefits to hybrid printing, there are also limitations for PSPs to consider.
For those that utilize two different ink sets within one unit, there are some limitations in regard to speed and color. “For businesses looking for production speed it’s more ideal to run a single ink set with dual CMYK to double production output. Secondly, for companies where color is the biggest concern, investing in a machine with a seven- or eight-color single ink configuration will offer an expanded color gamut,” shares Nelson Harris.
Peters points out that for hybrid, all-in-one printing units that include a built-in heat press or calendaring system, each process is reliant on the other, so for example if the heating system fails, the entire machine is unable to work.
Daplyn admits that there are potential limitations of the chemistry if the ink is not optimized with a hybrid system. “If an ink is designed for paper printing, the print is made and dried before a dry process to sublimate the dye from the paper to the fabric. When printing direct, all the ink components ultimately end up on the fabric and so the chemistry must be carefully managed. It is important to consider any chemicals for skin safety in fashion applications.”
He says in certain situations, the other materials contained within the ink may bleed from the print even after fixation, causing blemishes or apparent print or image defects. For that reason, often a sublimation ink printed directly to polyester requires a post-wash step before the final use.
It is also important to balance the differences in printing on paper versus fabric and what that means in terms of color performance, ink drying, and image sharpness. “One final limitation can be with black ink,” offers Daplyn. He says the selection of chemistry for direct versus transfer printing is typically a bit different and so a fully hybrid sublimation black ink may require a small compromise in color shade to ensure applicability to both print methods. “As such, the choice of ink is really the difference between a true hybrid solution and a process adaptation requiring close management.”
Syverson points out that there used to be many limitations in hybrid dye-sub systems, particularly in the overall color. “Direct and transfer prints used to have a larger difference in appearance, with direct looking less vibrant than the comparable transfer print.” However, the differences in print quality are largely eliminated today. “Print providers want to have the maximum in flexibility in their equipment as applications and requirements may change over time, necessitating additional solutions. By investing in a flexible system up front, print providers can be better prepared for these changing demands.”
Lily Hunter, senior product manager, Roland DGA Corporation, says it is important to understand what the customer is looking to produce and determine whether or not a hybrid/multifunction printer is the best option. “Direct to print is a great choice if the majority of the business is creating flags and signage that require heavy ink saturation. But, with direct to print, you lose the ability to print details—certain fine details can get lost in the texture of the fabric, and you need to use coated polyester fabric to achieve the best results. Coated polyester offerings typically cost more than uncoated fabrics used in transfer sublimation, and there may be limited options. If this is the case, a transfer sublimation printer may be a better choice in some situations.”
On the Fence
Investing in a new piece of equipment is a stressful endeavor. When deciding whether to go with a hybrid or dedicated solution for dye-sub, there are some general considerations for PSPs.
Determining a business’ primary goal is essential, says Nelson Harris, pointing to fabric versatility, color, and production speed as critical factors.
“The most important factor to consider is if the hybrid choice is going to serve the market you are targeting and its end product requirements,” agrees Donovan.
PSPs should consider the needs of their clients along with the ability to enhance their capabilities as far as finances, space, carbon footprint, overhead, and resources, suggests Peters. “Trade shows, events, and entertainment venues directly benefit from textile printing and a huge opportunity exists for small to large sign and print shops in these areas,” he adds.
“Print providers should look at their curret applications to determine the best fit. The latest generation of hybrid dye-sub systems do blur the line a bit as the range of products possible from a direct system is, in most cases, the same as a dedicated transfer system, with the benefits of lower consumables and higher overall throughput with an inline print system,” offers Syverson.
The size, speed, and reliability of the printer is a consideration, suggests Hutcheson. “Do you need the productivity afforded by a ten-foot device?” She argues that features like offline calendaring add to the productivity since a print provider is not tying up their printer waiting for the calendaring process to complete.
“If on the fence, a print provider should take a look at what they are printing today and tomorrow. However, since one is not able to see the future, it is always valuable to cover yourself and go hybrid,” suggests Tom Wittenberg, large format industry relations and events, North America, HP Inc. “For example, if prior to the pandemic you had equipment that only allowed for printing direct to fabric—soft signage, you would not have been able to pivot quickly as many companies were able to do, and get into the rapidly growing home décor market, which spiked during the pandemic.”
In the Details
There is a scientific component to these multi-purpose devices that makes them tick. Chemistry differences between dye-sub transfer and dye-sub direct must be managed in a hybrid printer.
Both direct and transfer dye-sub processes have their advantages and disadvantages, and if you’re new to the technology or are looking to invest in a dye-sub system, Hutcheson believes it pays to understand the benefits and limitations of each.
Nelson Harris explains that direct sublimation inks are better suited for products that require high ink penetration into the textile. “Direct sublimation inks require coated polyester fabrics, where the coating acts as an ink acceptance layer. These inks are fixed to the fabric with a heat press. Direct sublimation inks achieve better ink penetration due to the direct process allowing more ink to be placed directly on to the fiber. The direct process chemistry and application make it ideal for polyester flags and backlit applications where ink penetration through the textile is of utmost importance. Additionally, direct sublimation inks are ideal for high-end swimwear, so the white of the textile is not shown when stretched.”
Hutcheson explains that dedicated dye-sub direct inks have a higher molecular weight, which provides for a high degree of lightfastness. This is especially important in applications like flags and banners. “The primary advantage of direct disperse for this application is deep penetration and saturation of the ink into the fabric. The result can be more muted or less vivid colors and softer, less crisp text. On the flip side dedicated dye-sub transfer inks have a lower molecular weight, which results in slightly reduced lightfastness. With transfer paper, during sublimation, the ink doesn’t penetrate far into the substrate, remaining close to the surface. The end results are vivid images with clean, crisp text and fine detail.”
“Historically, the chemical makeup of hybrid inks for dye-sub would cause the ink to dry more slowly, creating sacrifices in color saturation on transfer paper,” says Syverson. He explains that this challenge is eliminated by inks that dry quickly on fabric and paper without giving up saturation, sharpness, or vibrancy.
Daplyn points out that the main difference between the processes is in the application of chemistry to the fabric. “In a transfer process the ink is printed to paper first and the transfer of the dye from paper to textile is a dry process, so in theory only the dye moves from the paper to the polyester. For this reason, the selection of other materials in the ink to help print performance and image quality has few limitations.”
He explains that when printing directly to the textile, all the ink is applied to that piece of fabric. “As such, it is critical to manage which chemicals are used and what influence they could have on the ultimate performance and compliance of the final product.”
Many companies will print paper transfer inks directly and apply a post wash to remove any chemicals. “A true direct sublimation or hybrid ink will have carefully tuned chemistry to eliminate that requirement and limit the process steps without compromising the color or application performance,” says Daplyn.
The difference in penetration is a critical consideration. “A liquid ink applied to textile will typically penetrate further into the fibers and so it is important to control the penetration to ensure the color strength is not reduced and the image sharpness is maintained,” he adds.
Some dye-sub inks, like DuPont Artistri, are formulated with a clear carrier to pull double duty. “You still have to calibrate you printer for different fabrics to maximize output,” explains Donovan.
Looking to the Future
Is the future hybrid inks that support both transfer or direct dye-sub or two separate ink sets? It depends on the needs of the PSP.
Daplyn sees a move to more flexible production methods and hybrid sublimation printers allow for that greater freedom in application. “With the number of installed systems, there will certainly be a need for paper transfer inks in the mid-term,” he predicts.
While a hybrid ink can work well in a transfer process, Daplyn admits there are some small compromises which may not be preferred, if not essential. There has been strong growth in direct sublimation with a view to it minimizing the environmental footprint by reducing water, waste, and process costs. There is certainly room for a true hybrid solution with the correct ink to deliver the best of both worlds for the future.
Peters believes in the potential of hybrid inks simply for the cost savings and convenience of achieving more with one machine as technology advances to ensure high-quality results when printing to more than one application.
“Ultimately, many print providers are looking for flexible solutions long term and equipment manufacturers are seeing this. If a print provider can have a system that is flexible and can change with their needs today and in the future, I see demand for hybrid-style systems continuing to increase,” says Syverson.
“There are companies in the market that focus on only one or two markets and do very well, so they don’t have the need for a hybrid dye-sub printer. However, there is also a strong demand for companies desiring the versatility that hybrid inks provide, allowing print providers to enter into multiple markets rather than just a few. An example here is focusing on soft signage versus printing soft signage and also being able to provide the home décor and fashion markets with products,” comments Wittenberg.
Goodearl points out that hardware purchases are major investment decisions for display graphics providers and when solutions arise that allow for higher quality and productivity with a single printer, it can set the direction of buyer demand. “We have seen the momentum in the display graphics market consistently move away from having separate printers or inks for direct versus transfer applications. Right now, this is a market primed for growth and recovery as soft-signage heavy verticals, such as the trade show industry, come back following the pandemic,” he offers.
Donovan says the demand is product/market specific. “The fabric in the soft signage, flag, and home décor markets doesn’t change on a yearly basis like the apparel market. In these markets, a hybrid system has a long productive life. In the apparel market, where fabric style varies greatly, it is anticipated that the paper transfer option will remain,” he suggests.
Hunter agrees, adding that a hybrid system with hybrid inks may be good for low volume, or to get business ramped up. When volume/production increases, it may be best to add dedicated printers with separate ink sets for direct to fabric or transfer sublimation.
Digital dye-sub printing is attractive for a variety of applications. However, both direct and transfer are viable options. The good news is that it’s not necessary to choose just one. Hybrid dye-sub printers enable the ability to sublimate directly to a textile, or to transfer paper, all in one device.
Aug2021, Digital Output