Screen Printing - August/September 2019 - 15

DTG (left) and dye sublimation (right) are two digital decorating techniques commonly used as alternatives - or as a complement - to traditional
screen printing. Photos courtesy of One Off Printing, left, and Pic the Gift, right.

THREE DIGITAL DECORATING TECHNIQUES:
A PRIMER
1. DIRECT TO GARMENT
Direct to Garment (DTG) printing most closely resembles
traditional screen printing. The process at a basic level
involves loading a shirt onto a platen that indexes underneath
an inkjet printhead using special ink that will bond to the
fabric once cured with heat. On light fabric and garments, the
process uses CMYK 4-color ink. For dark fabric, or any white
in the design that isn't created by the white of the garment, the
process requires pretreatment of the substrate. Many users buy
pretreatment application devices; alternatively, blank garments
pretreated during manufacturing are becoming more readily
available. The pretreatment is a sodium-based solution that
begins the curing of the white ink. The white ink contains
titanium dioxide, which starts to cure when it comes in contact
with the pretreatment, allowing the CMYK inks to be printed
on top of the white, instead of the white ink just falling into the
shirt. It's a bit like the concept of flash curing an underbase in
the screen-printing process.
DTG is great for short-run, full-color printing onto cotton.
Manufacturers are working on pretreatments for polyester
and some products on the market now, but cotton still seems
to be the go-to for DTG. The benefit of this printing method
is a nice, soft hand and the ability to print one to 16 million
colors with no setup - just put the art in the computer and
push print. It's not an economical technology to employ for
long runs or low- to mid-range production of one- or two-color

work when compared to screen printing. Some decorators are
now using DTG to add personalization to screen-printed shirts
or to create contrasting texture between the thicker plastisol
inks of screen printing and the soft hand of DTG.

2. SUBLIMATION
Dye sublimation is used with polyester fabrics. The process
takes a special sublimation ink and transfers it to a polyester
or polyester-coated surface with the use of even heat and
pressure through the chemical transformation of sublimation.
The pigments in the sublimation ink convert from a solid to
a gas at different temperatures. When heated, the pores in
polyester open and the heat transfers the pigments into the
polyester, permanently bonding the color into the fabric.
The pigments are translucent, so any existing color in the
polyester will change to the color of the pigment. White inks
and underbases aren't possible with this process, therefore
most sublimation transfers are done on blanks that start
white and the entire surface is decorated to change the
background color when needed.
Dye sub imprints are not only permanent and withstand
as many washings as the garment can handle, but the colors
are also bright and vibrant. Another advantage to sublimation
is that you can't feel the ink on the garments because the ink
becomes part of the polyester. They breathe well and can be
sold as an athletic advantage due to the moisture-wicking
property of the fabric. Polyester's popularity as a garment
choice continues to grow as the feel of the fabric continues to
improve - gone are the scratchy polyester leisure suits of the
AUGUST / SEPTEMBER 2019

Screen Printing - August/September 2019

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