Screen Printing - February/March 2018 - 20

Left, a stacked rock base
overprinted with multiple
colors. Right, a black
base overprinted with
metallic gold between
HD layers, with red
flake suspended in
the clear.

stencil take a bit of "voodoo" as well to clear the finer details
in the image.

On-Press COnsideratiOns
Developments in ink technology and newer formulations introduced in recent years allow for a much broader range of effects
than ever before, while making many of the more familiar products more forgiving in production. But there are some important
printing considerations when printing these specialty products.
First, the planar relationships of the platens to the heads,
squeegees and floodbars, and off-contact distance must be equal
and consistent. This is particularly important for effects that
require an exact ink deposit thickness. Many special-effect inks
require a flash after printing if they cannot be printed last. They
may require an additional cooldown station after the flash as well.
In our shop, we may also choose to use a heated iron or roller
with various papers to help get the textures we want at different
stations within the print order. Sampling plays an important role
in developing these specialty printing applications successfully.
We do a lot of testing to determine the optimum placement of the
special-effect screens, which in turn dictates where the flashes,
cooldown stations, and on-press treatments will be.
Because we use different meshes and sometimes thicker
stencils for these inks, the print can require a steady, slow flood
coat with heavy pressure to fill the stencil with the ink. Then
we set the print stroke at a medium to fast pace with decreased
pressure to transfer the ink from the stencil to the garment.
The flood and print strokes require some finesse to get just the
right pressure, speed, and off-contact combination. Choosing
the squeegee itself takes a bit of know-how, too. Sometimes
we want a sharp though soft edge, but we obviously don't want
the squeegee to roll over. The best way to accomplish this is a
triple-ply, duel-durometer blade. For textures, we frequently use
65/90/65 and 55/90/55 blades. Various squeegee profiles such as
bevels or round edges can be useful in certain applications as
well. With water-based inks, we often use a hard durometer such
as an 80. Using different squeegees and floodbars can help you
create some very interesting effects.
Specialty applications usually require a bit more attention
to drying requirements than traditional prints. The ink deposits
can be much thicker, and with some water-based inks, the water
must be driven off before curing can take place. Both of those
conditions mean the print often needs to spend more time in
the dryer chamber. Typically, the conveyor belt speed will need
to be reduced to get the additional drying time required, or the
20

screenprinting

temperature increased, or both. With special-effect inks, dryer
settings can dramatically influence the final appearance or
texture of the print. Because these inks often require different
curing parameters than standard products, be sure to refer to
the product data sheets. It's also a good idea to do wash tests
when trying out techniques to be certain of durability.
Keeping detailed, accurate records is critical. Documenting
how the process and inks react in production is vital to success
and your ability to repeat the results. Having everything as standardized as possible ensures CPR (consistency, predictability, and
repeatability), a concept we learned years ago from Mark Coudray and from Joe Clarke's book, "Control Without Confusion."
Once you are in control of the process, then you can begin to
manipulate it. Combining effects allows you to develop exciting,
truly original new looks. Before trying this, take the time to learn
how each effect behaves on its own and which ones work well
with others. These multiple-effect applications require testing
and control of as many variables as possible. Sampling and
investing time in research and development will help you learn
to produce these types of special effects efficiently, and are an
important step in your journey to becoming a specialty printer.

there are nO rules
Specialty applications present some challenges, but you can
overcome them with some basic separation techniques, screen
making procedures, ink adjustments, and on-press tricks. As
Albert Einstein said, "Imagination is more important than
knowledge." Specialty printing doesn't come in a can: The
things you learn through sampling and production will be as
valuable as the product information from the manufacturers.
Success does require planning and careful documentation, but
it also takes a willingness to break the rules.
Specialty printing is lucrative and customers will pay more
for it, removing you from the commodity pricing model. It will
improve your bottom line. Tackling these applications will also
improve your skills and help you gain additional control over your
process, giving you a better understanding of the production
variables. It's exciting to keep up with these embellishment
methods as they evolve, all part of being a true specialty printer.
Lon Winters is the president and founder of graphic Elephants / print
this, inc. His nearly 30-year career in garment printing includes being
named as director of production for Ocean pacific at the age of 21. He
is a frequent speaker and author, and his companies have won over 50
awards in international printing competitions. He was inducted into the
Academy of Screen and Digital printing technologies (ASDpt) in 2013.

Table of Contents for the Digital Edition of Screen Printing - February/March 2018