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| tools for fixing "pinholes", to prep a burned screen for printing |
1. TIPS for exposing and developing, plus instructions on how to get your artwork photocopied onto vellum
2. proper LAYOUT of positives when exposing including how to do it for this first screen burning, when you have to place three positives
3. HOW TO PREP A BURNED SCREEN for printing-- Fixing pinholes, taping-off, and masking-off
4. different kinds of "POSITIVES"and what THREE you need, to be ready to burn!
And how, when you are ready to burn, to come get the:
SCREEN BURNING CHECKLIST/INSTRUCTIONS
from me, to follow while burning! (with a partner!)
TIPS and HIGHLIGHTS:
VELLUM POSITIVES
-your artwork must be BLACK. However it looks in black, on white paper, is exactly how it will print! The artwork creates the vellum positive... which creates the stencil... which creates the print.
-TO MAKE A VELLUM POSITIVE OUT OF YOUR ARTWORK... put your originals/artwork into the "TO BE COPIED" folder in order to get in photocopied by me, onto vellum. Your name and period # should be on the front (unless there's no space). You will get it back in your period's "VELLUM COPIES" folder. Remove both the vellum and original artwork from the folder, you might need the original again to make another vellum copy.
GETTING SCREENS FILLED
-your screen must be DRY when it's put
into the rack to be filled (with emulsion). Emulsion does not stick to wet screens. If you're in period 2 or 3 and your screen is slightly damp, it will dry by the time I fill the screens. Do NOT put a dripping-wet screen on that rack, or you could get other screens wet!
-only reclaimed/blank screens needing to be filled, to be burned the next day, should be put on that rack. Normal screen storage is in the racks in the "screen drying room".
EXPOSING the EMULSION
-your filled, unexposed screen will be in the gray cabinet in the darkroom, unless I had to fill a large number of screens or you've left it there a couple of days. Then, check the wood cabinet.
-after you remove your screen from a cabinet, close the cabinet door! please please please. Those safelights have weak beams, but eventually the light will expose the emulsion if the door is left open.
-also, make sure you close the darkroom door before you open a cabinet! Even if you turned off the Main Light in the sinkroom. You never know...
-there are white tape lines on the glass of the exposure table. Keep your screen inside those lines! to prevent glass-breaking accidents. Trust me.
-lift the exposure table lid CAREFULLY and lower it carefully! No broken fingers, please. It's never happened. It's not going to happen. Because you're going to be careful.
-the toner/ink on the photocopied vellum positive blocks the light when exposing the emulsion, regardless of whether the vellum is right-side-up or flipped over.
-if you have a 400# screen, come talk to me before you burn the first time (if I haven't yet given you exposure-time adjustment instructions). Your exposure time is less than the other screens.
DEVELOPING the STENCIL
-if you think you won't have time to develop AND dry the stencils before the class period is over, don't get your screen wet-- put it back in the darkroom cabinet
-please please please please please... turn the water OFF after using a hose in the sinkroom!!! This means pushing the handles DOWN (that you pushed up, to turn on the water). Even though it seems like the water is "off" when you're not spraying, it's leaking out of the right hose (water waste!!) and building up pressure in the left hose (bad for the hose!! it'll bust). PLEASE PLEASE PLEASE. Get in the habit.
-whenever you are using a hose in the sinkroom, KEEP THE OUTER DOOR (to the classroom) CLOSED. Even if it's not an issue of light vs. safelights. I realize it's super-loud in there with the water hitting the screens... but it's loud in the classroom too, and we (I :) don't need that extra sound!
DRYING YOUR BURNED SCREEN
last week, you learned how to use the AIR COMPRESSOR
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| instructions for use are posted on the compressor itself |
(for step #3 of the burning process: Removing the emulsion residue from the stencils)
-if you let the screen dry on its own, the 'water' inside the stencils has emulsion residue in it, which will dry into a film in the stencil and subsequently block ink from passing through it. Therefore, you need to force it dry with compressed air, "blasting out" the residue.
-the air compressor is outside because it, like so many other things in here, is annoyingly loud
-FOLLOW THE POSTED INSTRUCTIONS FOR USE! turn it OFF when you're done using it, so it doesn't explode, please.
-after you've used the air compressor to get the stencils clear of moisture/emulsion residue, you have to let the rest of your screen dry before you can fix/tape/print. Do not use paper towels to do this. Paper towels have fibers that get caught in the screen and block your stencil when printing; you'd just have to get it wet and dry it all over again. And again, without paper towels.
-if you're in a rush to dry the whole screen, you could use the air compressor, or just prop up your screen outside in the sun to hurry the process
-if you're NOT in a hurry, please put your screen on a drying rack to continue drying
-before the screen is fully dry, it might look weird to you-- the emulsion is streaky, lighter pink in some spots, etc. This is normal! When it's fully dry, it will be an even, darker pink.
"FIXING PINHOLES"
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| the dark spots are where pinholes were "fixed" with emulsion |
WHAT ARE PINHOLES?
WHY ARE THERE PINHOLES?
HOW DO YOU "FIX" PINHOLES?
WHEN DO YOU FIX PINHOLES?
WHAT HAPPENS IF YOU DON'T FIX PINHOLES?
-Aaahhh, the questions of life.
In a nutshell (less than came out of my mouth today :)
WHAT? Tiny holes in the emulsion. NOT holes in the screen-- the screen is MADE UP of holes :)
WHY? A number of reasons. Maybe there was a speck of gunk on the exposure table that blocked the light when exposing. Maybe your screen was greasy/not reclaimed well, and the emulsion didn't stick properly. Maybe you used paper towels to dry your screen and the fibers left behind caused them. Maybe there were bubbles in the emulsion when I filled it, and they popped into pinholes. Maybe a miniscule rat took a teensy bite. Who knows. But, there are almost ALWAYS pinholes, at least on. If you ever get a screen with ZERO PINHOLES?? come show me, because maybe the world is ending.
HOW TO FIX? They have to be blocked with something. Tape works if it's a large area/galaxy of pinholes, but usually you want to use emulsion. (tape washes off). Using a brush, dab/cover the pinhole with a little emulsion, on the PRINT SIDE (so the squeegee-side doesn't become bumpy). It takes 5-10 minutes before the emulsion dabs dry enough to: set the screen down to tape it, or: print.
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| the brush is cleaned with WATER, and your gentle fingertips. Takes 10 seconds. DO IT! Brushes are found on (and returned to) my desk. Emulsion is in the top left drawer by the portfolio cupboards. |
WHEN TO FIX? 1. After the screen is FULLY DRY. For one, the emulsion won't stick to a wet screen. For two (is that English? :), you can't SEE those teeny holes when the emulsion is still wet and soft and slightly expanded.
2. you fix them BEFORE YOU PRINT. Duh.
3. also... it's easier to fix pinholes after you've taped-off... otherwise, you have to wait for the spots of emulsion to dry (takes up to ten minutes) before you can set it down flat to tape it. So tape it first. Common sense, yo.
WHAT HAPPENS IF YOU DON'T FIX? Well, if light goes through, ink goes through, right? Which means, your screen print will include little tiny random dots of ink. Which, contrary to popular belief and student rumor/wishful thinking, do NOT look like "...a galaxy of stars, Miss Doezie!" It just looks like pinholes, and messy. Also, it'll lower your grade for not prepping right, etc. Boom.
TAPING-OFF SCREENS:
Remember how so many of you were freaking out while I demo'd how to use the tape dispensers, because you thought I was "wasting" tape? Well, at this very moment as I type, I can hear some students trying to tear/use tape and saying "this is so hard!!"
hahahaha validation!
Anyway.
Taping-off: covers the OPEN AREA between the edge of the emulsion and the frame. You have to tape it off to cover it, so ink doesn't go through when you're printing!
TAPE-OFF ON BOTH THE PRINT SIDE AND THE SQUEEGEE-SIDE. The tape should make a seal to overlap the emulsion and the frame. On the squeegee-side, the tape should go partway up the side of the frame.
-You don't have to "tuck in" the tape in the corners, on the squeegee-side.
-Press the tape to make a good seal
-taping-off on the squeegee-side keeps ink from going through the open areas, helps you with cleaning the screen; and prevents ink from going into the cracks of the screen between mesh and frame, which damages it.
-taping-off on the print side is precautionary, in case the tape lifts up while printing and ink seeps under/through. Those 15 seconds of taping could save you HOURS of TEARS. As in tears from your eyes. As in crying, because you ruined your shirt.
and THAT... is plenty for now!
Doezie out.
