QUESTION: Why
are my exposure times changing? I use an exposure calculator as suggested
but I am seeing a change every week. I have not changed my emulsion,
and I am using a metal-halide single-source exposing unit. Wassup?
ANSWER: Occasionally, I run into this
technical problem related to the fact that metal-halide lamps age and
lose their light-broadcasting strength. The alignment of the glass particles
caused by repeated exposure
to heat causes a frost-like haze to form in the glass, called “crazing.”
When a bulb’s glass crazes the glass now becomes a light filter
choking off the (actinic/UV) light that exposes the emulsion.
This particular problem is most common with metal-halide
systems that are not equipped with a light integrator or where the light-sensing
and –measuring probe is not working correctly. Check your light
integrator or make sure you replace your outdated or low-end model for
a metal-halide exposure unit that is equipped with a light integrator.
QUESTION: I am having problems
with my exposures. I can’t get the image to spray out without
“scraps” stuck in the mesh, even though it’s exposed
completely. I have to underexpose and carefully blot and baby the screens
to prevent scumming and delamination when I develop the stencil. Even
with all this care the stencil has breakdown problems when I print.
What am I doing wrong?
ANSWER: It is likely your positives.
Far too many printers suffer with poor positives, using inexpensive
laser printers
and translucent paper vellum, or try to use standard transparency film
in their inkjets from the local office supply. This film or paper is
often not as clear or transparent to UV light as it needs to be, and
the black will suffer from holes in the print or be far too transparent
to block enough light for a good exposure.
Many will tell you it is the black of the positive (referred
to as D-Max) that is the important thing, while others will say it is
the clear of the film (D-Min) that does the trick. Both are correct
but both are missing the main thing: it is the contrast from one to
the other that is important. To solve this problem you will need to
upgrade to a better way of making your positives, such as a special
package inkjet, high quality ink, and RIP (yes, you must have the raster
imaging processor), or one of the more expensive film-output devices.
QUESTION: How do I learn this vector
graphics program? I’m just not getting it! I need to be up and
running now and don’t have the time for this frustration!
ANSWER: The first answer is that there
are many training programs for learning both vector graphics programs
and Photoshop, in DVD, online, and book form. Be aware that these graphics
programs have
a large learning curve. Every time you purchase a program it will come
with a manual; you learn the program just as I and many artists have
done: with mouse in one hand and manual in the other, one step at a
time. Even a novice will be able to produce simple art within just a
few hours of practice.
With a second look I would also point out that you may
be barking up the wrong tree. If you do not have the time for working
with graphics, why are you trying to be an artist? There are several
graphics services available online and at trade shows that will produce
excellent vector art and email the files directly to your inbox. Also,
you may want to consider one of your local area freelance artists; many
are surprised at how reasonable the charges are, and costs of the services
are something that you pass directly to your customer (with a markup,
if you wish).
QUESTION: I am about to upgrade
from my hobby-level screen printing equipment and want to know the best
way to buy new stuff. Any advice?
ANSWER: First I would suggest that
you attend a large regional or national trade show that will have the
most if not all of the manufacturers’ equipment on display, and
give them all a good “kick in the tires.” Once you decide
what brand you like, there are several ways to save more than just a
few bucks on your new equipment needs. One way is to find several dealers
of the same equipment brand on the Internet and get quotes on prices
from as many as possible. One of the best ways is to pre-order equipment
from your manufacturer and take delivery of that equipment at your next
regional screen printing show, saving shipping costs and likely getting
a significant discount. You can find out if your manufacturer will be
at your regional show by checking the show exhibitor list or calling
them directly about their plans. Printwear Shows are listed on the website
nbmshows.com.
QUESTION: I am currently using the
traditional multi-chemical screen cleaning method with an ink degrader,
emulsion remover, stain and ghost remover (when needed), and a degreaser,
and wanted to know if I can skip or remove a step or two to save time
and money.
ANSWER: First, skipping an important
and needed step will not save you time. What will happen is that you
will end up spending much more time on problems caused by a process
that produces a less 
than optimum product. The second point is also one of the nice things
about this industry: that is, we have new ideas and products every few
months. Chemical products are one area of the industry where lots of
work and development is aimed and now there are combination products
that will do two or more steps in one. At the same time, there is confusion
as to what the products do, so it is up to you to research the product
to see what will be accomplished with its use. Several products now
combine an emulsion remover and a degreaser in one step, so there currently
is a misconception out there that you may not need a degreaser step.
You do, but there are lots of combination products that do effectively
combine two applications into one step.
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