ALTERNATIVE PROCESS TUTORIAL #12
BUILDING A UV LIGHT BANK

Illustration #91: Gum Photograph Copyright © 1995 by Tom Ferguson Click on image for larger view	Illustration #92: Cyanotype Photograph Copyright © 2000 by Tom Ferguson Click on image for larger view

This tutorial is optional. Many alt printers work happily in the sunshine and outdoors!

Most alternative processes are highly sensitive to blue and ultra violet light, and quite insensitive to the yellow and red light. Two of the best sources of blue and ultra violet light are the sun and certain fluorescent lights. Unfortunately the sun varies in intensity due to time of day, time of year, haze, or pollution levels. Pollution... can you tell I live in Southern California? If you continue with alternative process work, you may want to build a bank of UV fluorescent lights. This will allow you to work indoors and is both more convenient and consistent than sun printing. These instructions are for a unit large enough to print 11x14 (or 8x10 or 4x5) negatives. The project can be sized up or down to suit your needs (different sized and powered bulbs may then be needed). All sizes and materials are in USA measurements. For the rest of the (metric) world, you will need to do some converting.

While all fluorescent bulbs emit some UV light, the "F15T8/BL" series bulbs are specifically designed for it. These are not the black lights used for posters. They are white frosted bulbs that look like a conventional household fluorescent bulbs. They are made by GTE and Sylvania, and can be obtained at most good lighting shops (see materials and sources page). You will also need fixtures for these bulbs. Most hardware stores will have wall or ceiling mountable individual fixtures for 18" (15 watt) fluorescent bulbs. Make sure that these fixtures are not longer than 22 inches.

Buy the Materials listed in illustration #93. Use a jig saw, or bare saw blade, to remove any diffusion panels from the fluorescent fixtures. You want the bulb to be completely exposed. Next, measure the height of your fixtures with a bulb installed. Also measure the height of your contact frame. Add these numbers together, then add another 2-1/2 inches. As an example if your fixtures are 1-3/4 inches and your contact frame 1-1/4 inches, then your total would be 1-3/4 plus 1-1/4 equals 3 plus 2-1/2 equals 5-1/2 inches. Use this number as "Total Height" in illustration #94.