Impressions - April 2024 - 20

Have an array of squeegees of various durometers.
Photo by photo_gonzo - stock.adobe.com
able to use the " absorbent " paper setting (bond paper, for example) on
the printer, so that the printer spits out more ink. The film has a coating
that absorbs the ink; therefore, more ink translates to a darker print.
Executing Emulsion
One of the first things on my agenda when visiting a shop is to review
the freshly developed screens (screens that are ready to go on
a press). Can I see the edge of where the film was? This could be a
sign of under-exposure. Is the screen tight enough? It doesn't have
to be in the highest level of tension, but it should be in the ballpark.
Can I feel where the image begins or ends due to the thickness of
the emulsion? If I don't, then we don't have enough emulsion.
I don't care if it is a 110 mesh or a 330 mesh, you should always
feel where the image is if you close your eyes and touch the screen.
When reviewing the emulsion, you should not see pinholes. If there
are a bunch or the screen maker blocked them out after developing,
then you may have a dirty shop/glass or film or you may simply not
be degreasing your screens properly.
Let's do a test: Now that you've reclaimed your screen (or starting
off fresh with a new screen that has been degreased), open a fresh
container of emulsion. Coat the screen according to the emulsion
manufacturer's recommendation. I typically do two coats on each
side with the ink side last. Let the screen dry with the ink side up.
After the emulsion is dry, take some electrical tape, something
that is positively not going to let light pass through. Place it in the
area you would normally place your film on the screen and expose
it. If your screen comes out well, then the film quite possibly could
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ImpressionsMagazine.com April 2024
be the issue. If your screen does not come out well, let's troubleshoot
what the issue could be.
For that, do the same test but this time, take the tape and place it
on the image area. Leave it on the drying rack for a day or two, with
the tape and shirt side up. Then simply wash the screen out. If the
area you placed the tape on washes out before the outside area does,
then you have light contamination in your dark room.
Store your dry coated screen in a light safe place. One of the top,
if not THE top issue, is storage of your coated screens or even your
emulsion before it is applied. Emulsion is light-sensitive. But I think
many printers underestimate how important it is to store both the
liquid emulsion and the coated unexposed screen in the darkest environment
possible.
Sometimes when I'm working in an area with a lot of light (maybe
there is a window nearby) or I must walk from the exposure area
to the wash-out area, I will put the screen in a black plastic bag or
even a cardboard box, anything to protect the screen from the light
poison before washing it out. You can even turn off the wash-out
booth light and only turn it back on after you are sure you have
washed out the screen.
Several months ago, I was asked by a busy shop to help them troubleshoot
their processes. The main thing they were concerned about
was printing the best white on a shirt. When I walked into the shop,
diagnosing the problem was not difficult. Their screen room had
open doors to the rest of the office, so the room itself was not even
dark. In addition, the exposure table was also located in the room
emitting light every time they used it. This is the worst-case scenario.
To top it off, the washout booth was located immediately around
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Impressions - April 2024

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