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Exposure Information

At one time I used an old style wood contact printing frame for paper size up to 11x14 and image size up to 8x10. For larger size you really need to be using a vacuum press to keep negative and paper in contact! Now I always use my vacuum press. Vacuum presses can be readily found as used items in the graphic arts/printing trade. As digital sweeps the printing industry vacuum presses are being scraped. I just picked up a 30 X 50 for around $250.00. I highly recommend using one for all sizes. The one disadvantage is that if you are using one of the processes that requite you to inspect the print during exposure there is no split back to allow you to look at the images during exposure. Me, I've never been able to tell much by looking at the print during exposure.

If you want clean white boarders you need to mask the negative I use a graphic arts material called "plasti-mask". I find it easier to cut straight and in general easier to work with than ruby lith but many people like the ruby lith material. There are also as many light sources as there are printers. Remember we are working with UV waves! Very bad for eyes and skin so wear sunglasses and protective clothes and or keep light enclosed in unit. You can find commercially made ones ranging from a few hundred dollars into the thousands. I made my own which is composed of 16 uri 36 inch 85 watt bulbs with internal reflectors. It is powered by 4 electronic 66 ice cap ballasts the bulbs are about 1/8 inch apart. This unit is super bright and Fast! Info in suppliers section. The sun is also a viable light source. If combined with a Metrolux unit and a UV filter over the probe you can get very controllable results, but some very long exposure times.

The Metrolux II w/ probe measurers the quantity of light as apposed to the time/light relationship. This is so much better as what we are really interested in is the quantity of light. The Metrolux takes into account clouds passing over the sun as well as the bulb in you units getting old, voltage spikes etc. it sells for about $385.00 from Calumet.