By Cassandra Balentine
Textile printing is hot. There are several methods that allow for printing onto textiles—direct print, printing directly to a fabric using ink such as latex or solvent; direct dye-sublimation (dye-sub), where the sublimation process occurs directly on the fabric; and transfer dye-sub, when a graphic is first printed onto transfer paper and then sublimated into the fibers of the fabric with an external heat press.
The transfer dye-sub process is known for impressive output quality, as well as the lasting bond it forges through sublimation between ink and fabric. However, it does require the added step of printing to paper.
We often focus on the printing technologies and the inks that enable dye-sub, but here we look at the heat transfer paper that makes the transfer dye-sub process possible. This media is coated to carry an image printed with dye-sub inks so that it can be transferred to the final media when heated.
Many considerations go into selecting the best transfer paper for a job, including weight and tack, and it is often based on the end product, such as apparel or signage.
Lily Hunter, product manager, textiles and consumables, Roland DGA Corporation, notes that while the weight of dye-sub transfer paper can range from 45 to 160 gsm, the most common weights fall between 90 and 110 gsm. She adds that some dye-sub transfer papers also have a light tack, which is activated by heat. This type of paper is ideal for apparel applications and can help prevent ghosting. She adds that it is important to remember that when sublimating, coated transfer paper must be used and the fabric needs to be 100 percent polyester for the best results.
In terms of cost, she estimates that quality transfer paper will range anywhere from 10 to 12 cents per square foot—for non-tack, and tack typically runs about a penny higher per square foot. “Using high-quality paper ensures consistent results and releases at least 90 percent of the ink,” explains Hunter.
Potential Challenges
As with any process, technical challenges arise with transfer dye-sub. Multiple steps and materials leads to additional potential for error. Ghosting and blurring are common issues if the proper paper is not used.
“Loss of color or graphic integrity are also areas to monitor for superior image quality,” offers Bruce Walker, Apps Tech and client solutions – NE, Sihl Inc.
Rob Repasi, VP of global sales, Beaver Paper & Graphic Media, Inc., suggests that bad output is often attributed to poor color management between paper, ink, printer, substrate, heat press, and the RIP. “If any or all are out of sync, the result is bad or less-than-optimal performance,” he warns. “Sharpness and definition is based on how well the paper transfers the image printed. If printers can’t translate a good image to paper, then that is as good as it gets.”
“Users are often reluctant to invest in custom ICC profiles for different fabrics and attempt to use generic profiles, resulting in poor image quality and high ink consumption,” says Michael Pender, president, Supply55, Inc. “Properly profiled fabric results in superior image quality during the sublimation process.”
In addition to color management, Pender sees environmental controls, such as room temperature and humidity, as a common challenge. “Humidity and room temperature play a role in the quality of the finished product,” he notes, adding that a well-managed print environment—including proper color management, humidity, and temperature, results in high-quality images during the sublimation process.
Residue of ink on the paper is also a concern. “If the paper does not transfer well, meaning more ink gets left on the paper, that will adversely affect your end results,” says Hunter. She explains that both high opacity and vibrant colors are important when sublimating, especially for apparel applications. “Likewise, if you’re dealing with backlit signs or see-through flags, the colors need to be dense in order to pop.”
“It is always best to select leading brand inks and paper that are manufactured to the highest standards,” adds Howard Gerson, president, BestBlanks. “This will go a long way to avoid issues,” he adds.
With poor quality paper, Hunter admits fine lines and detail will not transfer well. “This could result in having to redo the job several times to achieve the desired result. You may also have to lay down more ink to get the intended vibrancy, which there are dangers associated with, including buckling of the paper,” she continues.
Selecting on Specifications
Many factors play a role in transfer paper selection. In addition to tack, which helps prevent ghosting in apparel, fast-drying features enable a continuous workflow even when printing at high speeds.
Different transfer paper products are designed for different applications. Walker stresses that proper compatibility affects the ability to produce a quality product. “What we refer to as our Sport version has a tackiness that adheres to the fabric during the transfer process. If a fabric is stretchy, it can misalign and shift the image during the transfer or calendaring process,” he notes.
Similarly, Repasi says Beaver Paper’s TexPrint TT Thermo Tack products are ideal for apparel. “This product, when heat is activated during the transfer process, will stick to the garment of a cut apparel piece in a flatbed or clamshell heat press.”
For those that need faster print speeds, transfer papers with fast drying options are best. Walker says Sihl’s Superdry version is available for fast production. “Anything less for high-speed transfers would not have stable graphics and could ghost the image or muddy the colors,” he suggests.
“Printer speed directly impacts paper dry time,” agrees Pender. Supply55’s Prime Sublimation Transfer Paper utilizes Full Release Technology, which provides, “superior dry time and ink release during the sublimation process.” It is available in 105g tacky paper, 105g non-tacky paper, and 85g non-tacky paper and compatible with all aqueous dye-sub ink, polyester-based fabrics, and polyester-coated substrates.
Roland’s new DSM-RTP Roland Texart Sublimation Transfer Paper is 95 gsm, which Hunter shares is not too heavy or too light, but, “just right for handling a wide range of applications.” It is also fast drying to accommodate heavier ink loads without slowing workflow.
Sihl offers Universal for general everyday use; Sports; Superdry; and Fashion, which is light and delicate for high-end fashion and suitable for light fabrics. Walker says they are designed for receptivity with aqueous dye as well as solvent/aqueous ink sets to be transferred onto polyester-based fabrics—poly blend fabrics also work.
SpectraJet offers three types of sublimation papers. SilverBack3 is used with oil, water, and solvent sublimation ink. Roll sizes are available from 17 to 126 inches. Lite 40 is available for water- and solvent-based sublimation ink. Guy Spinelli, president/CEO, SpectraJet, says that Lite 40 is about 20 percent less expensive than most sublimation paper.
It is important to note that you can only transfer onto light substrates with sublimation. Repasi explains in most cases it would be white, but if you had a range of light shirts to print onto, than each color should have its own profile for optimal color.
Gerson warns that sublimating to a dark fabric—including black and other dark colors—results in the image not showing.
Walker points out that there are printable transfer media options outside of dye-sub transfer. “Printable transfer media is different for light and dark fabrics as the entire printed transfer media adheres to the fabric. The easiest way to describe this from Sihl is an ‘iron on’ transfer for sports jersey numbers and other applications,” he says.
Surface Control
While the primary focus of this article surrounds dye-sub for textiles, it is also possible to use the process on hard surfaces, including metal, glass, and ceramics.
Walker suggests that fundamentally hard surface transfer paper can be used interchangeably with paper used for textiles. “Pay attention to the application process and notice the behavior of the substrate to be transferred to,” he explains.
If there seems to be a tendency for the transfer paper to shift or slip due to transferring on a vertical surface or incline, or due to rapid production of multiple items, an individual may wish to choose a slightly tackier transfer paper to help ensure stability. “For quick, clean separation, one may alternatively decide not to go with a tacky transfer paper,” advises Walker.
Spinelli agrees that the paper for both hard and soft surfaces is interchangeable, however the user may need to adjust ink loads and heat press time when working between the two.
Hunter says that with soft substrates, both tack and non-tack papers are used, whereas most hard substrates use non-tack paper. “Sometimes tack paper can leave a residue or hue. Hard substrates are less forgiving and tend to show imperfections, so heat tape is used to secure the paper to hard surfaces instead of tack paper,” she offers.
Repasi states that only solid surface coated papers will work on hard substrate printing. “Most sublimation papers are carboxymethyl cellulose, or cellulose-coated papers. They do not work on any hard surface printing.” Beaver Paper’s solid surface coated paper is TexPrint XPHR. This product is a multiple-purpose paper also used for soft substrates.
Transfer Element
Heat transfer paper is treated to carry the printed image to its final destination. Considerations for this substrate largely depend on the final application, but optimal results also involve proper color management and controlling the work environment.
Jul2015, Digital Output
