Screen Printing - February/March 2018 - 19

Prints that aren't exactly What they seem
In our shop, we like to say, "If we make something look like something it ain't, it always works." We don't just print ink: We
make it look real. Here are just a few of the things we do:
"Screenbroidery"
Cork
n Sponge and Blister
n Rock and Sand
n Faux Twill

Leather
Suede
n Diamond Plate
n Sequins
n Nail Heads

Animal Skin
Duct Tape
n Scotch Tape
n Masking Tape
n Doming

Tacks
Tackle Twill
n Burlap
n Denim
n Chenille

Distressed and Vintage
Staining
n Scented
n Four-Color Process
n Simulated Process

High Density
Sculpture
n Shatter and Brittle
n Clear and Gel
n Suede and Plush

Caviar
Silver and Gold
n Black Light and
Glow in the Dark
n Many More!

Other non-PVC solutions include "acrysols," inks that
behave much like a plastisol on press. A variety of textures are
available in this category. Silicone inks, which are also PVC
free, allow for some great applications, particularly on polyester
compression fabrics because of their low curing temperatures
and elastic characteristics. We use thickeners to stack some
nice HD effects, and the gels are truly clear and ultra shiny.
We've used them to develop some great doming effects.
Some techniques such as reflective and glow-in-the-dark
inks have reemerged better than ever over the last few years.
You don't have to live with that nasty green glow or dingy gray
reflective any more. Photo-chromatic and thermo-chromatic
inks that respond to light or temperature have come back
around as well. Remember scratch and sniff? Think of a
Hershey's Kiss logo that smells like chocolate. Countless such
scents are available today.
As we know, colored metallics, shimmers, and glitters have
been around for a while and can be executed in any number of
ways. Using a receding base that fades into the garment during
the curing process, we're able to get a hand-sprinkled appearance
that leaves the glitter on the surface. We sometimes suspend a
low percentage of the flakes into a clear and overprint that onto
other colors. Ink manufacturers have taken silver and gold to
a new level with products that look like liquid precious metals,
more convincing and durable than ever.
Flock, foil, and other inline transfer applications remain
popular in some fashion brands. While the equipment can
be expensive, these applications can also be overprinted to
achieve a variety of new effects.

Good Artwork Is key
Remember, it's a "garbage in, garbage out" business. Every
successful garment embellishment begins with the art. The
designer must become familiar with the processes and should
also have a grasp of their variables and limitations. Taking
these into consideration at the design stage will result in
artwork that is finely tuned to each technique's characteristics
and capabilities. This makes the final print more precise and
easier to run in production.
When we're planning for a specialty application, we try
to design the special effects as fairly basic elements within
the image. Shadows or highlights are a good place to start.
We avoid fine detail and identify any limitations that may be
imposed by the application. We keep in mind that the inks may
move or change shape. For example, we know puff grows in
multiple directions in the dryer, so we allow space for this to
avoid smearing. Using chokes, spreads, gutters, and traps can
be a big part of successfully executing many of these effects

on press. A skilled designer and separator will create room
for special effects in the print sequence as well by using fewer
heads to achieve the desired result.

Control BeGIns wIth the sCreen
It's true with every type of screen printing: If you control
the screen, then (and only then) do you begin to control the
process. Advancements in stencil systems and meshes have
raised the bar considerably on what can be achieved with
screen printing. Many special-effect inks are quite thick (or
thixotropic) and more difficult to get through the mesh than
standard inks. Some water-based inks can dry in the mesh.
Using a mesh with sufficient open area and reaching an
adequate tension level (at least 30 N/cm2 on standard mesh
counts) allows the ink to transfer to the substrate.
Most specialty inks require a low mesh count. We generally
use mesh counts of 110 (threads per inch) or below. Large
glitters and beads need mesh counts as low as 13 to 24. At the
other end of the spectrum, mesh manufacturers have realized
that garment printers can also take advantage of the thinthread mesh technology developed for other markets. At a
reasonably high tension of 25 to 30 N/cm2, the smaller thread
really helps increase the open area of the screen. With thicker
specialty inks, 80/70 (80 threads per inch with a 70-micron
thread diameter) can be the most effective mesh count. The
80/55 mesh is useful because the smaller thread diameter
allows ink to more easily pass through the stencil, but it can
be very fragile. Water-based inks work nicely with thinner
meshes, including 150/48 and 225/40. With meshes ranging
from 305/30 to 350/30, we can even run water-based simulated
process halftones as fine as 85 lines per inch.
Remember that the combined thickness of the mesh and
stencil is directly related to ink deposit. If we want a softer,
smoother, or thinner print, we use a higher mesh count with a
thinner stencil. Conversely, achieving prints with more texture
or thicker ink deposits will require a lower mesh count with
a thicker stencil. Because we often want a very thick ink
deposit with some of these applications, we modify our typical
coating techniques a bit for the very low mesh counts and specialty emulsions and capillary films that are involved. Capillary film is available in thicknesses ranging from 20 microns
all the way up to 1000 microns; we usually stay in the range of
100 to 400 microns for best results in specialty applications.
Even with extreme HD effects, it can be easier to stack two
or three sheets of capillary films together rather than trying
to get full release from a 1000-micron film. Most thicker films
use pure photopolymer sensitizers to allow for faster screen
exposures. Developing and washing out the properly exposed
february / march 2018

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