Working with Our New Exposure Unit
Notes by Enid Keyser and Kat Murray
Stencils or films:
You need an opaque ink for drawing stencils, such as Rapidograph pen or acrylic paint pens.
Sharpies are too transparent.
a B or 2B graphite pencil will do.
Conté crayon or stabilo pencil also works well.
You can use semitransparent drafting film 3-4ml for drawings.
Also, you can use photographic films printed on Pictorico (inkjet transparency paper type, 2 sides, print on rough side). If you buy an inkjet transparency and need to know the side that the printer will print on, lick your finger and stick it to the corner of the transparency to see if it’s the sticky side.
Can be found at AL ScreenProcessors in Trussville. They also supply aluminum squeegees and blades which are preferable to the wooden type…easier cleanup.
Screen and Emulsion Coat:
First: degrease your screen. Use screen degreaser, or if there is no degreaser in the studio use Bartender’s Helper or dawn dish soap. Use the scrub brush that’s in the washout booth and massage the degreaser on both sides of the screen. Wash out. If degreasing screen allow it to dry before coating with emulsion.
Second: The studio has a non-toxic brand of pre-sensitized photo-emulsion. Only open and apply in the dark. We have light safe lights you can turn on. You can choose to coat both sides or just one side of the screen. If only coating one side you coat the paper side. After coating scrape excess emulsion in scoop coater back into the emulsion container with a spatula. Scoop coaters are located in the box with the squeegees.
Let dry overnight in the dark out closet next to the wash-out booth
Amerigraph Exposure Unit:
We worked with photographic transparency films.
Place the image face up, just as you would see it. If there is text, you can read it. It helps to tape the transparencies down with a small bit of clear tape at corners.
With the safe lights on, place photosensitive screen on top, paper side down.
To adjust “vacuum” and “exposure”, press down and adjust with U or D buttons. “Vacuum” is length of time it takes to reach full vacuum (set at 50 seconds); “Exposure” is light units.
The Vacuum should be set, so the only adjustments you’ll need to make is the “Exposure”
Exposure Times:
For computer-printed films, or very opaque hand-drawn films 23-25 seconds
Hand-drawn stencils they have a varied exposure time of 15-18 seconds
I recommend testing exposure times to see what is optimal for your materials.
After exposure, immediately take to the wash station and wash out. You should be able to see a faint image on the screen. The exposed parts of the emulsion polymerize, the other unexposed or lightly exposed areas wash out in degrees.
Note: pressure washers have different tips. Use the green or white tips for developing the screen. Do most of the spraying on the paper side. When using the pressure washer make sure the water is on and then turn the pressure washer on with the on button. When you are done using the pressure washer turn it off, turn off the water, and lastly but most importantly make sure to spray the remaining water out of the pressure washer hose.
Reclaiming screens:
There is a diptank full of emulsion remover right in front of the washout booth. Remove lid and let screens sit for 5 mins and then flip and sit another 5 mins. I think the screen could take less time but are also okay if you leave them in longer. After that you will carefully take them out, place the lid back on and wash them out with the power washer.
TIPS FOR CLEAN UP:
If when coating your screen, make sure to wipe up any emulsion that gets on the floor and surfaces. It is easy to clean when its fresh but impossible when its hardened. A wet paper towel or rag will do.
After putting coated screen in the drying rack make sure to clean the scoop coater and spatula used in coating in the sink. Wash out and put away.
When you are done printing, make sure to clean the ink out of the screen and throw away ink you do not want to save. Its best to not clean the screen out in the washout booth with a lot of ink still on the screen.
I like to use a spray bottle and paper towels/rags to clean my screen of ink before I take it to clean it more in the sink.
Prints will be dry very soon after you print. By the time you are done printing your prints will be dry. I would gather them up and store them in your flat file and not leave them on the rack.
Extra Information:
Screen mesh can range from 230 very fine to 195 a bigger weave.
The studio will soon have a blackout curtain and a red light.
Squeegee Blades have different durometers or combinations thereof.
Hard blades are good for detailed prints and flat hard surfaces, and softer blades are best for
fabric or other textured surfaces. The shop squeegees are in varying shapes, and I would suggest buying your own.
Policy:
Each person will buy their own emulsion. It must be the non-toxic brand.
If you have coated your screen, plan on exposing the next day, or the day after at the
latest. We have very few places to store screens in the dark!
Please email katharinejoanmurray@gmail.com If you have any follow up questions!
It’s a lot of info, so its okay if you have questions.