Wednesday, April 09, 2008

Solar Printing and Silkscreen Exposure Unit

There has been a thread going in the Baren Forum regarding solar printing and UV exposure. I decided to post a few pictures of an exposure unit I set up...

Contact Frame made using a hinged frame with black craft foam backing to press glass tight. This wore out quickly, I highly recommend getting a contact frame for this if you're serious about doing it a lot, try ebay.

Went to Target and bought a $12 wire shelf set up for 3 shelves. bottom shelf is about 2 inches from table top. The top shelf is set so that the lamps that will be hung using tie straps are about 14" from the frame. Yes I did remove the glass from the lamps. This system worked great but you must take care of safety!!!

Please click these pictures to open them for a better view. Your safety is important. Use your back arrow to return to this page.

You see this setup? Notice the industrial UV vision protection, do go to the hardware store and invest a few dollars in a pair, your eyes as an artist are your most valuable tools...I have a timer that automatically shut the lights off at the end; you can get one at Adorama for $150 or you can get one for about $10 from ebay like I did. I did end up timing some of my exposures longer than a minute and used a kitchen timer. I simply stayed in the room and hit the powerstrip toggle the second the buzzer went of. The reason my exposure times took longer was because I kept my lights so far from the contact frame. This prevented the melting of the solar plates but the long time in the heat still melted my aquatint screen.

OK now how to hang out with your lights without getting sunburn by the uv rays...easy I made a case from black foam core that drops down over the top. I cut a little door hinged with duct tape in the front and a cut a hole in the back for a small fan to suck out the heat. I used little blocks of wood to hold the case up off the table about an inch for ventilation. Close the door when before turning on the lights or you will get sunburned!

It is possible to set this system up, it does take some trial and error to get your timing right. You should make sure to ventilate things well. In addition to the little fan in the back I use a little clip on fan to push air at the bottom crack.

I kept the room dark enough to use during daylight as well by putting black foamcore in the window. I used a 40W yellow bug lite to adiquately light the room without exposing the plates. I did a lot of internet research on this settup as my online college classes had us spending a fortune on specialized products. I found in my research that many of those special products were discovered by artists using regular household stuff...I also use this set up for exposing silkscreens.
Some of Patti’s research on Halogen Exposure Units
8. Halogen Bulbs can be used and there is no complication of reduced light emission after a set amount of time. It simply burns out.
a. both photo-flood and halogen bulbs can be used immediately, there is no need for warm up. Also both are best as 500 Watt bulbs used in pairs or fours.
9. Mercury and Metal Halide Bulbs provide true and intense light.
a. both need at least 5 minutes to warm up to their true intensity before using for exposure of photo-polymer plate.
b. you should protect your eyes from extreme light.
c. need a shutter box set up since light must remain on between turning on and exposing of plate to various screens and transparencies.
1) 1996, Dove article on how to make an Exposure Unit Box, Printmaking Today.
My UV setup is simple and inexpensive. For the Imagon plates I use two 500-watt halogen worklights suspended about 14 inches above the plate. My average exposure time is about two minutes using a halftone laser positive. For the solar plates, I use 4 black light bulbs (BLB) suspended about 6-8 inches above the plate. My average exposure time is about 3-5 minutes with a laser halftone. Both plates are developed using a tray of water (for solar plate) and water with soda ash (for Imagon). The plates are then re-exposed to UV light for about 3-5 minutes to harden the plate

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