The Platemaker is a letterpress plate made by exposing a transparency to UV light.
Table of Contents
1/ Make your Pictorico transparency
We have detailed instructions on how to do that under: Photopolymer Plate Image Prep.
Regular silkscreen transparencies, drawing on transparency, etc. will not work.
Any experimentation outside of Pictorico transparencies will be at your own cost. For example, if you wish to do some drawing with a china marker or super-opaque ink, you will have to pay for your plate whether it succeeds or not.
2/ Print your transparency
You can either have it printed by your professor or TA (there are size limits on what we can do) with the Epson 3880. See Paper Store Prices for current price and size limitations.
Or, you can get it printed at Graphic Arts (cash/cheque only!) Ask for a "photopolymer letterpress platemaker right-reading emulsion side up negative."
3/ Buy your plate
Buy a plate from your professor or TA. Confirm with them the size you are working with. See Paper Store Prices for size & pricing.
Do not bring it out of the exposure room until after you have exposed it because it is light sensitive. This will ruin the plate.
4/ Overview
A general overview of the platemaker:
Expose the back of the plate (the opposite side from where the protective film is) for 20 seconds as a pre-exposure.
Flip the plate over in the exposure unit so the front faces the transparency films (emulsion to emulsion) and make sure they looked as well registered as possible when the vacuum goes on.
Expose, wash out, dry, and post-expose.
Platemaker settings and times
A note about settings: these can vary! Please adhere to any alterations communicated by your professor. The platemaker is finicky and is dependent on your media. In short, please ask before exposing if you are unsure!
- Pre-exposure time: back of plate for 20 seconds (no vacuum needed)
- Exposure time: 240 seconds
- Washout time: 290 seconds
- Dry Time: 720 seconds
- Post-exposure cure time: 260 seconds (no vacuum)
Machine Overview
4/Detailed operation
| Step | Name | Info | Photo (click to enlarge) |
|---|---|---|---|
| 1 | Turn on | Turn on by pulling the big red knob, and then press the power button (circled in blue) |
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| 2 | Figure out settings | Make sure the numbers on the unit correspond to the numbers assigned to you by your professor, TA, or technician. The ones in the photo might not be good for what you are doing. See exposure for suggested times. Do not attempt to change these settings without consulting a professor, TA or technician. You can always use the timer on your phone or the kitchen timer located in the exposure room if you are using different exposure times than the ones programmed in the machine. The LED numbers on the unit are in seconds. | |
| 3 | Preheat & ventilate. | Pre-heat the washout solution & dryer by pressing the corresponding button. Turn on the central ventilation in the exposure room. The switch is near first litho station. | Solution heater ON/OFF button
Dryer ON/OFF button
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| 4 | Pre-exposure | While you are waiting for the unit to heat up, you can pre-expose & expose your plate. PRE EXPOSURE: Lie your plate emulsion side down (the emulsion side has a peel-off clear coating, which you can leave on for now) in the exposure drawer. Put it on top of the translucent cover with the peel off coating facing down. Set a timer on your phone for 20 seconds or set up the kitchen timer in the exposure room. Press the exposure button to start exposing, and after 20sec, press it again to stop exposure. | Exposure button:
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| 5 | Main Exposure | MAIN EXPOSURE Now you can expose your plate. Peel off the transparent covering. Lie your plate emulsion side up in the exposure drawer. Carefully lie your two transparencies emulsion side down on the plate. The emulsions of the plate and of the transparency should be touching - if you have any text, when you look at it in the drawer, it will be the wrong way. |
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| 6 | Main Exposure & Vacuum | Carefully roll the covering over your plate + transparency. Close the drawer (carefully!) and press the vacuum button. The vacuum is very important to have on, and easy to forget! You can tell the vacuum is working when the Vacuum Gauge needle hovers at a steady place above 0, usually around 0.03. Then press the exposure button to expose for desired amount of time. It is a good idea to USE GLOVES for this and all the following steps. | How to roll over the cover:
Vaccum on/off button:
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| 7 | Washout | When your plate is done exposing, you will wash it out immediately. Make sure the water is at least 1/8" above ALL the bristles in the wash out bath. Use the flashlight on your phone to double check. If not, refill using the "clean h20" bucket in the Light Sensitive cabinet. Open the top cover of the wash out unit on the platemaker. Stick your plate to the black/green rubber on the bottom of the lid. Use the squeegee to clean the rubber backing off off before and after. Stick it on with the emulsion side of your plate facing away from the rubber; in other words, the relief side will be facing toward you. Close the lid, latch it shut, and then press the Washout button. | Washout On/Off Button:
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| 8 | Dry | When the washout has finished, you will now dry your plate. Put it emulsion side up in one of the drying drawers. Careful, the drawer handles can be hot. Press the dry time button and wait until it beeps to tell you it is done. | |
| 9 | Cure / post-exposure | Put your plate emulsion side up in the exposure drawer. Expose it for the time listed in the exposure section. Turn off the machine. | |
| 10 | Finish | Now you can turn off the unit. Leave the washout bath lid open. To clean up:
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Troubleshooting
Plate doesn't wash out completely:
- wash again
- expose for less time
- double up transparency
Doubling Up Your Transparency
If you are getting inconsistent results, you can double up your transparency to increase the UV protection of the black ink.
Double up the films, and register them as close as possible on the light table, taping the edges together with clear tape while still on the light table. Make sure they remain registered when you shoot your plate.
Double Transparency Settings:
- pre exposure: 20 seconds (no vacuum)
- exposure time: 240 seconds
- washout time: 290 seconds
- dry time: 720 seconds
- Post exposure time: 260 seconds (no vacuum)