• DTF is a better option than direct-to–garment (DTG), which requires fabric pretreatment.
• Preparing the image for printing is important. However, hot-melt adhesive can also be applied. This hot-melt adhesive uses hot-melt powder that is made from polyurethane resin and is ground into an adhesive powder.
• DTF can be used to decorate many fabrics. It does not require any fabric pre-treatment.

By Johnny Shell

Introduction

Direct-to film (DTF) is a new technology in decorated apparel that allows you to print your designs on polyethylene terephthalate(PET) film with water-based pigment inks. The transfer technology means that the design will be printed in reverse order to traditional digital print. The image is reversed so that its orientation is mirrored—the CMYK colors (i.e., cyan, magenta, yellow, black) are printed first, followed by the white ink. After the ink has dried, it is powdered using a hot-melt adhesive. The image can then be transferred to clothing using a heat press after it has cured.

What’s All the Buzz About?

DTF printing is more efficient than direct-to-garment printing (DTG). DTG printing requires fabric pre-treatment. DTF can also be used on fabrics such as nylon and polyester, which are difficult to print with DTG. In addition, there’s a much lower learning curve for printing DTF transfers compared to DTG. DTF allows the user to decorate more fabrics and colors than dye-sublimation. DTF is faster than heat-transfer Vinyl because it doesn’t require cutting or weeding.

DTF, like other digital printing technologies, is excellent for creating photorealistic, full-color images. Only the range of inks used limits the color options. DTF is able to handle fine lines, small text and detailed images. However, it is possible to have difficulty with color profiling if you are not familiar with ICC profiles and color management. To create a white printing layer and mirror the image, special RIP software must be used. This will ensure that the transfer prints are in the right orientation.

The majority of DTF printers are from China. They are often modified Epson printers or platforms using Epson printheads (models commonly include 1–4 printheads). You can add additional printheads to jet white, CMYK and fluorescent channels. The number of printheads will affect the printing speed. However, there are three types of printers available:

1. Slow (25–35 sq. ft./hr.)
2. Medium (80–100 sq. ft./hr.)
3. Fast (150+ Sq. ft./hr.)

Prices per square foot (includes PET film, ink and powder adhesive), range from $0.50 to $0.90. The washfast durability reported is over 100 washing cycles.

Preparing an image for print is very important. Hot-melt adhesive uses a hot melt powder made of polyurethane resin that has been ground into an adhesive powder. While there are no harmful emissions, the powder adhesive is exceptionally fine and can generate dust, so it’s important to wear respiratory protection when working with the powder. It’s also best to keep the inkjet printer at a safe distance from the powder coating process to keep adhesive dust from penetrating the sensitive parts inside the printer.

The powder is available in black or white, depending on the color of the fabric to be decorated. For printed PET film rolls, the best way to apply the powder is with an automatic powder shaker. However, it can also easily be applied manually using PET film sheets cut out. It is important to apply the powder adhesive evenly. Once cured, the transfer is applied at 315°F (157°C) for 15 seconds at medium pressure for cotton fabrics. You can reduce the time required to press heat-sensitive fabrics, such as polyester.

The newest offering in the industry is the CobraFlex DTF printer line. These devices do not require powder adhesive. This system eliminates the need for powder adhesive and the dust it can create. This is a trend in inkjet printer printing that allows for chemistry to be jetted alongside CMYKW and CMYK inks.

CobraFlex’s No Powder DTF Printer. Source: CobraFlex Printers

In just over two years, DTF has emerged as an “all-for-one” technology. DTF can be used to decorate many fabrics. It doesn’t require any pre-treatment and it is very durable.

The bottom line: Signs of Movement

While today’s OEMs have been slow to react to market demand, there are signs of movement. Eastman Kodak Company, for example, recently launched the KODACOLOR film-to-fabric ink system. The device comes with powder adhesive, PET film and an ink specifically for DTF transfers. Meanwhile, STS Inks (Boca Raton, Fla.) offers a device that uses Mutoh’s VJ-628, includes powder adhesive and PET film, and is branded with the STS logo.

Many OEMs, such as Epson and Kornit Digital, have promoted the ability for DTF transfers to be printed on DTG devices. They can use cut-sheet PET film or existing DTG Inks. It will be interesting to observe if other OEMs of equipment or ink producers decide to follow the DTF wave by creating dedicated printers. The future will be interesting, so please keep watching!

Johnny Shell is the Director of Keypoint Intelligence’s Functional & Industrial Printing Consulting Service. He is a recognized leader and printing expert with more than 35 years of experience in the industry. Johnny is an inductee of Academy of Screen and Digital Printing Technologies. It is an international body of specialists that honors distinguished, long-term, and exemplary contributions to screen and digital print and associated imaging technologies.