Uh, my lightbox is pretty primitive. Five 20 watt BL tubes sort of
taped together, leaving the bulbs about 2 inches apart. The prints rest on
top, about 2 inches from the tubes. The fan, a portable heater with the
element turned off, is just sort of pointed at the tubes.
I'm delighted the damn thing works at all. I'm tired of getting
frostbite trying to catch the 30 minutes of exposure time this time of year
here at 47 degrees lattitude. Thank you to all who provided the myriad bits
of advice on how to build one. NASA should be so well served.
As for exposure times, cyanotype chemistry is a LOT less sensitive
than gum. Gum takes about 1 minute in full sun (at my lattitude) and
cyanotypes take 6-8 minutes.
Kevin
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Kevin Crombie e-mail: kcrombie@montreal.com
387 rue Villeneuve est voice: (514) 849-7601
Montreal, P.Q. H2T 1M1