Screen Printing - April/May 2020 - 11

IMAGE 2

DISCHARGE PRINTING

UNCURED DISCHARGE

CURED DISCHARGE

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DISTRESSED ARTWORK

The name of the game for super soft feeling prints on
dark cotton shirts is discharge printing. For an inexperienced printer, this method has a lot of hurdles to get good
results, but it's also one of the most rewarding (see Image
1). The way discharge printing works is a water-based ink
will have a discharge additive combined with it, so when
it's printed on a garment, the discharge agent in the ink
discharges out the dye in the shirt fabric. It's similar to a
bleaching process, except it happens when heat is applied
to the ink. When discharge is done properly, the resulting
print will appear much brighter after curing because the
inks are now sitting on the original, lighter shirt color. If
you're considering discharge printing, it's very important
you contact your screen printing supplier to talk about
what you will need to test the process. There are several
things to consider:
1. Do you have a gas dryer that can cure a water-based
print? If you don't have access to enough heat and
airflow to properly cure a water-based print in your
current dryer, there aren't a lot of work arounds. You
can repeatedly run it through an electric dryer, but that
isn't going to be production friendly.
2. Do you have the right kind of emulsion and inks?
You'll need to make a hardened stencil that has additional water resistance to resist a discharge ink.
Getting water-based inks that work with a discharge
additive is also a necessity. You will mix just what you
need for the job as these inks typically don't last after
the discharge additive has been added.
3. Get comfortable with this process by taking a waterbased printing course. B-Unlimited offers a fantastic
training class called "Origins." They invite attending
printers to their studio for a couple days of intense
water-based training that includes discharge printing.
4. Learning how to discharge print well also involves
knowing what garments and fabrics work the best
with this type of effect. Many suppliers offer "discharge friendly" shirts that allow the dye from the
shirt to release well and leave the resulting print to
appear much brighter. Talk to your garment suppliers
and get some samples of their most popular discharge
garments so you can practice on these and learn without risking customer-ordered garments.
When creating good discharge prints, the separation
process will need to be done differently than a traditional
plastisol print. Particularly if you want the softest possible
print, a separation set for discharge will need to be created in a unique way. The print will have to be separated
with each color staying in its own space, not overlapping
other colors, and, most importantly, not be underbased. As
the dye of the garment is discharged out, the lighter shirt
fabric will simulate the underbase for the colors. It's a weird

APRIL + MAY 2020 | SCREENPRINTING

Screen Printing - April/May 2020

Table of Contents for the Digital Edition of Screen Printing - April/May 2020