On Thu, 14 May 1998, FotoDave wrote:
> If you have used the grow lamp, you must have a unit already, so I guess the
> easiest way is to replace the grow lamp with a black light or black light blue
> tubes (BL or BLB). I believe that for dichromated gum, BLB works better.
No Dave, for all of our processes that I've tested, the BLB is slower,
besides being three times the price. See my boxed inset on the bottom of
page 45 of Issue #1 of The World Journal of Post-Factory Photography,
titled "Blacklight Fluorescent Bulbs."
The light put out is the same, but the BLB has an expensive glass
that filters out the other wavelengths. However, since there are spikes of
sensitivity at many points on the spectrum, this actually cuts total
exposure.
Judy