Identifying Superior Screen Print Suppliers

Suppliers

If the quality of printing you are getting does not meet your expectations,
the reasons are easy to spot.  Selling a job that you are not proud to
deliver does not have to happen again.

Whether you are purchasing for resale printed shirts, caps, tote bags, signs and the
like, or you are the printer, you need to make sure the right tools are used
to print your job.  The tools include the screen, ink, substrate, emulsion,
printing press, and that is just for starters.  There are many choices
available for each tool.  These choices are not equal, and in combination
with choices of other tools can produce brilliant results or disasters.

We will identify which tools are best, and why, and then suggest how these tools can
produce new products for your customers.  When you show fresh new looks
in graphics your customers will respond with “wow,” and you will
have higher profit margin products.

Screen   A screen can be wood, welded aluminum, or retensionable aluminum.  Retensionable
means either three or four sides of the frame are tubes that can be rotated
to tighten the mesh through which the ink will pass.  Any person who has
printed even for a short time will say that tight screens are better than screens
where the mesh moves in the direction of the print stroke.

Mesh can be stretched very tight on any of these frames, but will relax to almost no
measurable tension over night.  The welded frame holds the tension longer
than wood frames, but only the retensionable frames permit taking up the slack
in the mesh.  Each time a mesh is retightened is can be tensioned to a
higher level.  The best screens have old mesh that has been retensioned
at least 5-6 times and have been used for at least 500 prints.         This
process works the elasticity out of the mesh so that the print results will
be more predictable.

The principal cause of heavy “bullet proof” prints is low tension screens.  Ink
may show on the inside of the garment for the same reason.  Images where
colors are not tightly aligned, or registered, to each other can be the product
of soft screens.  A dull image might be produced by ink pushed down into
a fabric so that the customer is seeing both the fabric and ink color.  Conclusion:
make sure retensionable screens are used that have been used on several jobs
before your job, and retensioned just before being used on your job.

Ink   Any screen printer will admit that some colors and types of inks are stiffer than
others.  Some are like clay in the manufacturer’s container.  Others
can be loose and soupy, or someplace between clay and soupy.  Quality
depends on consistency and predictability.

Ink should be like yogurt when printed.  If you stir yogurt up and remove the spoon
from the cup, the yogurt drops immediately from the spoon.  Ink can be
whipped and blended with additives like curable reducer, soft hand clear or
another ink to achieve the yogurt condition.  Very few inks are shipped
in this condition, and almost all inks need at least some modification.

Ink that is adhesive, remaining connected to the spoon when the spoon is 6” above
the container, acts like an adhesive between the screen and article being printed.  Adhesive
inks may drag the mesh in the direction of the print stroke causing ink to
smear and colors to bleed into each other.  When the screen is raised,
no ink should be on the bottom of the screen.  When ink goes through a
screen, but remains on the bottom of the screen, the image will have insufficient
ink and likely be dull or incomplete.

The next time you have a job printed, ask the printer if the ink is whipped and modified
to print like yogurt.  Ask if the ink is tested to see if ink on the spoon
is connected to the ink in the container when the spoon is 6” above the
container.  You will be surprised by the answers you get to these basic
tests.

Substrate  A substrate can be a hard, smooth surface like a sign, label or bumper sticker,
or a porous shirt, or textured surface of a tote bag.  The substrate can
be white, black or some other color.  A heavy deposit of ink on a hard,
smooth surface is more likely to smear, but the same quantity of ink may be
insufficient to produce an opaque image on a dark, porous or textured material.

Upon inquiry, the printer should tell us the mesh count, stencil thickness, type of ink and
other procedures to be used to compensate for the substrate condition.  A
response that does not, at a minimum, address these evaluative criteria – mesh
count, emulsion thickness and type of ink – is a precursor to unsatisfactory
quality.

Emulsion   Emulsion is a material in the mesh that blocks ink from passing through the mesh, except
where the image will be printed.  Emulsion can be applied as a liquid
to mesh or purchased as a dry sheet known as capillary film that is applied
to the mesh with water.  A liquid emulsion encapsulates mesh, but capillary
film sticks to the bottom of the mesh.

Capillary film produces better quality images, but is not widely accepted and used like
liquid emulsion.  Capillary film can be purchased in different thicknesses,
and can be laminated to create thicker coatings under a screen as a way of
controlling the amount of ink that is deposited to compensate for the substrate
conditions.  Screen printers who do not use capillary film extensively
do not know what they are missing.  You and your customer will be missing
the opportunity to produce the best quality images and new, high profit margin
products.

Press   A printing press provides the foundation to an image.  If the print surface
of the press moves when you press down, you will have a shaky foundation to
the print quality.  The color arm of the press should not move laterally
when down in the print position or allow any twisting when you try.  If
there are a multiple of print surfaces upon which garments are placed, they
should all pass under the flash dryer at exactly the same height.  This
can be checked when the flash dryer is turned off and paper taped to the dryer
to check the consistency of printing height and level of all printing surfaces.

If your work is being printed on an automatic press, do you hear “clang and bang,” feel
or see movement in the print head during the printing process?  A well
maintained press will only whisper, print without shaking, and not have to
be lagged into the concrete floor.

Curing    A common complaint with printed apparel is the ink fades or washes out, or can
even be picked off the shirt.  When you receive an order you can check
whether this will happen or not.  Stretch the image.  If it cracks,
the ink is not fully cured.  Try to pick the ink off with your fingernail.  If
the ink comes off, the ink is not fully cured.  Ink that is not fully
cured will wash out or fade from washing.

When ink does not pass your stretch or pick tests, return the garments to have the curing
job finished.  Curing inks is like baking cookies.  Soft centers
are under cooked or cured.  All inks should be like well done steaks
and not rare or medium cooked steaks.  All the printer has to do is run
the garments through the dryer again, but this time slower and on lower heat
so the heat penetrates the ink film without scorching the garment.

Positives   If shaded colors or so-called “process” work is the requirement, the “positives” should
be inspected.  Positives are the image on vellum paper or plastic that
allows light to pass through, except where the image will appear.  Shaded
or process images should appear as individual, dense black dots separated by
clear areas where no gray or black appears.  If the image is continuous
tone gray rather than individual black dots, the image quality will be poor.

Other Questions    Other questions you can ask to protect your
reputation for delivering quality include: (1) How far off-contact will you
be printing?  The mesh should be off-contact from a sign or other hard,
smooth material 1/32-1/16”.  The off-contact for a T-shirt should
be 1/16-1/8”.  A sweatshirt will be 1/8-1/4”.  (2)  Do
you sharpen the squeegees daily? The answer should be yes, but most will
say no.  A sharp knife works better in the kitchen, and we are cutting
ink to be laid down in thin, controlled deposits.

(3) Do your squeegee blades bend?  The answer will probably be “of course,” but
the answer should be no.  Bending blades are a sign of excessive squeegee
pressure that will splatter ink on a hard surface or drive ink into a fabric.  We
want crisp images lying on top of the surface.

These criteria to control the quality you will be receiving are also the starting point to
new product offerings at superior profit margins.  The market in apparel,
for example, has broadened from T-shirts to textures like pique golf shirts,
denim collared shirts, 600 denier tote bags and twill aprons.  Most of
this market is served by high priced embroidery.  The high price can be
charged, but the image printed with photographic quality, with fonts, details
smaller than ¼” and even dots reproduced exactly as they would
be in advertising, packaging and on stationary.

This new process requires the retensionable screen, capillary film, 3-D ink, and a press
that does not flex during the printing process.  Actually, layers of ink
can be laid one upon the other so bumps appear on a basketball to create a
realistic effect.  Images can be printed with the 3rd dimension that stands
off the garment.  Such textured images are sharper looking than embroidery,
more flexible and comfortable to wear, quick to print and deliver like any
screen printing, but high priced like embroidery.

So the next time you order screen printing, ask the right questions before selecting
your printer rather than risking losing a customer after you deliver the order.