Direct-to-film printing (DTF) is a transfer technique that allows users to print designs onto PET film with water-based pigment inks. This article provides an overview of the technology as well as a comparison to other printing methods.
- DTF printing is more efficient than direct-to-garment printing (DTG). DTG printing requires fabric pre-treatment.
- Preparing an image for print is very important. Hot-melt adhesive is applied using a hot melt powder made from polyurethane resin.
- DTF is a fast and cheap way to decorate fabrics.
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 be used to print fabrics such as nylon or polyester that are more difficult than DTG. In addition, there’s a much lower learning curve for printing DTF transfers compared to DTG. DTF can be used to decorate fabrics in a wider variety of colors and fabrics than dye-sublimation. DTF is faster than other transfer techniques like heat-transfer Vinyl because it doesn’t require any 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 can handle fine lines, small text, high-detail images, and even fine lines. 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.
China has produced the largest number of DTF printers to date. 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. Print speeds will vary depending on the number and type of printheads. The available printer models are also divided into one of the following categories:
- Slow (25–35 sq. ft./hr.)
- Medium (80–100 sq. ft./hr.)
- 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 the image for printing is important. However, hot-melt adhesive can be applied just like DTF. It uses hot-melt powder that is made from polyurethane resin and ground into 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. The press time for heat-sensitive fabrics such as polyester can be decreased.
The newest offering in the industry is the CobraFlex DTF printers. These devices do not require powder adhesive. The transfer adhesive prints simultaneously with the white ink pass. This eliminates the need to use powdered adhesive as well as the dust that it can produce. 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 and Movement
While today’s OEMs have been slow to react to market demand, there are signs of movement. Eastman Kodak Company launched its KODACOLOR Film to-Fabric ink system recently. 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.
Additionally, direct-to garment OEMs like Epson and Kornit Digital have promoted the ability for DTF transfers to be printed on their DTG devices with cut-sheet PET film or existing DTG Inks. It will be interesting for other OEMs and ink makers to decide whether they want to join the DTF wave and develop dedicated printers, inks powder systems, PET films, or inks. 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 respected 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. This international group of experts honors individuals who have made outstanding, long-term contributions in screen and digital printing and related imaging technologies for graphic and industrial printing applications.