Pushing ink through a screen is the most oversimplified way to explain screen printing.  Before digital artwork was in common use, there were many ingenious methods developed.
In Philadelphia, screen printing was also known as Process Lettering, and in 1973, Walt Huddell, Gary Huddell, and Geoff Traub developed an incredibly efficient way of process lettering; they used blank screens and paper stencils that they would lay UNDER the screen as they printed shirts and sweatshirts, and thus was born American Process Lettering—later to become AMPRO.  The initial process used a cut paper stencil that would be sent down the conveyor belt of their homemade dryer alongside the t-shirt with wet ink on it.  The process was an improvement in efficiency, especially for individual numbering, but still incredibly labor-intensive compared to more modern methods.

From there, printing evolved into a more traditional method where the silk screen has a liquid emulsion dried onto it (think of it like a wax) and then an image is burned into the emulsion using a film positive made of an arcane material called Rubylith film. “Ruby” as it was called, eventually evolved into a film positive which was printed on a digital printer with a specialized toner.  But in the beginning, full color images were often printed in a 4-color process using painstakingly hand-cut and layered ruby positives.  Our artist, John Cosgrove, hand-cut our ruby for over 25 years before the first of many digital revolutions.  He is best known for his photographic wildlife prints developed under Zooper Sportswear;  he made beautiful full color images of tree frogs, tropical fish, and whales- all made with hand cut film positives.

As the art and pre-production processes were evolving, the equipment for the industry was also becoming more modern.  Originally, our printing rigs were hand-made with angle iron and spring-loaded hinges. Those rigs were lovingly named “Junkyard Dogs,” and they still pull a pretty mean 1-color print to this day.  However, as the company and industry was growing, an equipment manufacturer called Precision developed an automatic machine called the Multiprinter. Known for it’s dramatic screen indexing movement, those machines were incredibly productive, durable, and designed to print many colors in perfect registration.  From there, M&R Inc. developed pneumatic, industrial multicolor presses that overtook the Precision equipment because of their deep understanding of the art of printing. The settings and configuration capabilities helped printing evolve from relatively crude stencils to fine art.


The biggest change to the industry in the ‘80s was a legal one.  Prior to 1981, it was legal to print college logos on apparel and sell them.  Crewneck sweatshirts were fashionable, and the apparel industry was selling beautiful, high quality, locally sourced sweatshirts with the names of local schools printed on them. However, once collegiate licensing was conceived, the apparel industry was reigned in and college sweatshirts were made through a small handful of channels, leaving smaller printers to history.  The apparel industry was still growing like crazy, so the onset of licensing was only a minor blow to larger domestic printers.


Once the United States had a flourishing apparel industry replete with large-volume screenprinting shops, fabric mills, cotton farms and
clothing manufacturers, and then NAFTA was signed in 1993.  Though globalization may have been
inevitable, NAFTA was a particularly cruel piece of legislation for many manufacturers.  Apparel printing and manufacturing is
extremely labor intensive. Many companies packed up their equipment and set up
shop in Mexico, decimating the apparel producing towns throughout the East
Coast.  As the apparel manufacturers
moved, so did the printing.  It started
in Mexico and gravitated further south as more trade deals were signed,
eventually settling in Honduras, Mexico, El Salvador and Nicaragua.

But… the domestic printing industry adapted, shrank and
persisted.  Then, Abercrombie developed a
business model that was favorable to printers. They imported their blank shirts
but didn’t commit to the decorating until they extensively tested each design
at their flagship stores and through their catalogs.  Pioneering a new business model, their nimble
approach to fashion (before the phrase “fast fashion” was coined) blew their
competitors out of the water.  Their print
preferences were simple and athletic, but preppy and vintage at the same
time.  The quality of their shirts was outstanding;
7 oz ringspun cotton fabric constructed with a back yoke and double needle
everything.  Their dyes were beautifully
done; their shirts were laundered after printing, and they developed
proprietary techniques for distressing their prints, which you would never
expect to find in the United States.
They taught the entire domestic apparel industry how to really “vintage”
a print through art, meshes, inks, and washing.
The industry went from making their prints as bright and indestructible
as possible to making them look like they had already been washed hundreds of times.


The next big earth-shattering disruption for domestic
printers was the re-introduction of polyester.
Just when we thought we had put polyester clothing behind us, too!  Under Armour rocked the boat with the
introduction of mass-market performance apparel.  They had developed some proprietary fabrics that
compressed muscles, kept athletes warm, and wicked away sweat.  While these garments were great for athletes,
they were very rough for printers.
Polyester fabrics are notorious for bleeding; the dyestuffs sit on top
of the (plastic) polyester fibers and can release into the air in a dryer.  That doesn’t sound so terrible, except that
the dyes release up through the inks we print with, turning them pink, blue or
some other “off” color.  Performance
fabrics were challenging, but polyester was also being blended back into
everything.  Triblends, biblends, and CVC
fabrics came onto the scene, and while they are dreamy fabrics off the shelf,
they don’t tolerate printing or washing that well.  Rayon also made its way into our t-shirts (now
called Triblends) and since Rayon is a substitute for silk, it changed the
longevity of the shirts.  They pill
faster than cotton/poly blends, and can’t withstand the heat needed to print

As polyester was working its way back into our wardrobes, digital
printing and Web companies really started to put the “Old School” printers out
to pasture.  Struggling to adapt to the
changing client expectations and struggling to compete with innovative
web-driven companies that know how to sell online (but may not consider
themselves fine art printers), many printers have been swallowed up by venture
capital firms.  There are precious few
large-volume independent screenprinting shops left- most have been purchased by
larger companies who excel at converting business through the Internet.

The newest technique
for apparel decorating is digital printing also called “direct to garment
printing.” Also known as DTG, this new method is beginning to displacing
traditional screenprinting, but there are some significant hurdles before digital
printing equals screenprinting in speed and quality.



Why is screenprinting
an art, and how does digital printing compare?


Digital printing is an emerging technology that may soon
displace screenprinting… but digital printing is rigid and slow.  Traditional domestic screenprinting presses
have controls and settings that would rival a Boeing 747.  Digital printers have far fewer adjustable
features- the ink has to be thin enough to pass through the print head, so
nuanced printing with different color opacities to create dimension is impossible.  This may be the future of the industry, but
it cannot rival traditional screenprinting… yet.

Screenprinting, on the other hand, is an artform that can be
manipulated and adjusted from the art department through to the print
technician.  Dozens of small decisions
are made before the first shirt gets printed, starting with the color
separations.  To screenprint a
multi-color design, the artwork has to be separated by each color for each
individual silkscreen. When a human artist can influence the color separation
process, they achieve the spirit of the design better than an automated digital
printer ever could.  Aside from choosing
colors, they are making an extraordinary number of tiny decisions to influence
the final product in ways that computers could not understand.

Starting in the art department, the design is evaluated
holistically alongside the garment to be sure we can render the print to the
client’s expectations.  The use of the
garment is also taken into consideration; if a product will be used outdoors,
or with heavy commercial washing, we protect the print using a variety of
methods.  The design is then color
separated using a combination of technology and manual manipulation.  Color choices, color order, and flashing (lightly
drying the print to “tacky” between silk screens on press) are specified and
prepared for production.

From the artist, the design is handed over to “pre-press”
where the technician decides what type of machine the product should be printed
on and hand-picks each mesh count for every color.  Most screenprints require an “underbase,”
which typically prints in a slightly lower (finer) mesh than the rest of the
colors.  “Mesh” is a reference to how big
the holes are in the silkscreen itself- bigger mesh holes allow for thicker ink
deposits.  Finer/higher mesh counts can
only allow thinner, more transparent inks to pass through.  High meshes are ideal for printing halftone
images, blending colors, and vintage printing.
The higher the mesh, the softer the print.  Print softness is always a high priority,
though some garments require a slightly heavier ink deposit to protect the
print from bleeding.  Many printers,
AMPRO included, have proprietary ink softening techniques that work in tandem
with the mesh count decisions made by Pre-press.  Careful selection of meshes ensures the best
possible reproduction of the art.

After the silkscreens are made by prepress, the ink
department begins its selection process.
As with the other areas of pre-production, inks are critical to the
quality of the final product.  Most
large-scale print shops blend their inks in house, giving them total control
over the viscosity (thickness) and accuracy of the colors.  Across most industries, Pantone Color Systems
are used for matching color; by standardizing the colors from shop to shop, a
company can safely print products at several shops with matching results.  Pantone color books are even installed into
Adobe Photoshop and Illustrator so that artists can specify the correct Pantone
ink color in the digital file.  Choosing
ink colors is more nuanced than people may realize.  Pantone standardized the colors, but that
does not mean that all ink/Pantone colors print alike.  Ink shades that are bright or fluorescent do
not withstand the rigors of the printing process as well as high-opacity colors
like white.  White has a very high pigment
load, as do many shades of grey, so they perform differently on a print run
than fluorescent pink.  Fluorescent
colors often need to be dried on press or printed last so they don’t lift off
when the next color prints on top.  Depending
on the way a piece of art prints, it’s sometimes necessary to choose a
darker/lighter Pantone shade so that the end result matches the requested
color.  Some inks are “shaped” prior to
printing to make them thicker or thinner depending on the purpose of the color
in the art and the endurance needed on the print run.  Ink color, order and viscosity influence the
art at least as much as the color separations and mesh counts.

Digital printing
equipment utilizes only thin inks of the same viscosity, so it’s not possible
to take advantage of all the amazing things that can be done to ink before it
goes into the screens.  Hybridized
Digital Printing, a combination of regular screen printing and digital
printing, has the potential to overcome some of the ink transparency issues-
even allowing for the use of spot colors like Fluorescent highlights, metallic
highlights, or reflective areas.

The art all comes together out on the production floor; the
screens are married up with the inks and the goods, and the printers get to dig
in.  Printers have a variety of choices
and adjustments that allow them to take a group of screens and inks and render
it into ART.

Screenprinting variables and adjustments:

Squeegee selection is the first step; technicians
choose the durometer of each squeegee based on the color going into the
screen.  For “hard to print” colors like
Fluorescents and process inks, they typically use triple durometer squeegees
that have a soft printing rubber on the face, but a stiffer middle layer that
gives the squeegee enough rigidity to push the ink through the screen.

Squeegee angles are set at the same time the
squeegees and floodbars are set in.  Controlling
the angle gives them another way to control the (ink deposit) opacity of each
individual color.  More angle, more ink;
less angle, less ink.  If the squeegee is
standing straight up and down, it will skim the image in the silk and produce a
soft film of ink.

Pressure on the squeegee is often the first
adjustment that is made to each print head as the design is set up and is crucial
to success.  Similar to angle, the more
pressure, the more ink will be pushed through the screen. Applying pressure
that is too heavy pressure can cause the
lifting off other wet inks, “pancaking” the print, distorting
registration, leaving marks on the fabric outside of the print area, or losing
transparencies and dimension in the art.

Registration is another key component to
rendering the “art” of a print.  In this
one area, digital printing typically has the advantage, but that does not
compensate for its other limitations. Domestic apparel screenprinters have been
successfully registering full color images for more than half a century.  Registration is the process where all the
screens are lined up to make a print, and each color has to be perfectly
aligned with all the other colors to make this possible.  Innovations in the industry, such as Tri-loc has
greatly improved the registration process over the past 25 years.

Once the screens are registered and the
squeegees are set, the speed of the print head is set, color by color.  In a production environment, you want your
print heads to print at their maximum possible speed- but the overall quality
and dimension of the print are the top priority.  Setting your head speed faster will keep the
squeegee’s contact with other wet ink colors to a bare minimum though some inks
need slower head speeds to physically “clear” or push through the screen.

Off-contact is also adjusted along with the head
speed. The purpose of off-contact is to get the screen to peel and snap off the
wet ink it has just printed.  Too much
off-contact can distort registration, whereas not enough off-contact can
flatten the image and make the inks mottle.

Temperatures are also a huge factor in printing;
the fabric is printed between the machine pallet (the t-shirt is loaded with a light
adhesive onto a pallet so that it remains stable while moving from one print station
to another) and the screen.  The pallet
itself retains warmth from the flash cure units, which apply a bright burst of
heat to lightly dry the inks while printing.
Pallets must always be warmed prior to production so that printing
results are consistent from the first printed t-shirt to the last.  Inks also warm up and thin during the
process, so inks have to be managed carefully to keep the print looking
consistent.  Printing technicians make
constant adjustments to head speeds and pressures to accommodate the
temperature changes in pallets and inks.


Printers are artisans who wield a tremendous amount of influence on the
final result.  Printers can understand
the “spirit of the art” and what the product is trying to achieve more
intuitively than a software program attached to a bunch of print heads.  Perfectly composed designs require a human touch
when they are reproduced, which is why preserving the art of domestic
screenprinting is so vitally important.
Digital printing is the Kraft Mac & Cheese of our industry; it’s
vibrant, it tastes good, it’s quick and easy- but it doesn’t compare to the mac
& cheese our moms made.  While digital
and hybridized digital garment printing techniques are important innovations in
the domestic apparel market, digital printing is highly limited and should be
approached with a degree of cynicism for full color, photographic or fine art
printing.  Precious few high-volume
independent screenprinting operations are left in the United States; most have
been relocated to Mexico or further South- but we are committed to our
Philadelphia operation!

Understanding the differences between digital apparel
printing technologies and screenprinting should shape the discussion about
preserving this art form.  On the
surface, digital printing is able to reproduce at a higher resolution than a
screenprint, but the lack of control over softness, opacity, dimension, and
color cannot be overstated.  Picture Bob
Ross at his canvas, starting his background… what if he had to print his
background strokes at 100% opacity before he started on his happy little
trees?  I can almost picture these
beautiful Liquidtex acrylics- Burnt Sienna, Cerulean Blue, Cadmium Red getting
slathered onto the canvas at full opacity; it would be difficult to bring forth
dimension in a landscape using every ink fully opaque.

Even after painstakingly extolling the virtues of domestic
screenprinting, we haven’t even delved into the sentimental value of t-shirts,
and their significance to us personally!
T-shirts are the comfort food of our wardrobe as well as a vehicle to
declare love for a favorite team, school, musician, or (God help us) political
preference.  Making art on t-shirts is
the best business in the world, so let’s preserve our art and keep the domestic
apparel business vibrant and robust!