Smieglitz@aol.com
Date: 04/25/00-05:45:18 PM Z
In a message dated 04/25/2000 18:02:56:
<<> But here's something not touched on so far -- has anyone tested the light
> fall-off of the metal or quartz halide bulbs? In my experience, without a
> reflector, the cone of *even* light is relatively small. Of course I
> haven't seen these appliances, presumably they're configured for even
> light, but over what area????
>>An excellent point. It is difficult to get good uniformity on a large
plane with a bulb having a certain size filament or arc and a reflector
system even if additional optics are utilized. Uniform illumination is
a must
>>
In my tests, I used a Minolta Auto IVF meter to check the eveness of
illumination over the surface of the contact frame and adjusted the beam from
the FEL lamp until I was satisfied the illumination was even for practical
purposes. I'm sure a metal halide graphics arts printer is a better exposure
source for gum printing, but I don't have the $$$ to make such an investment
at the present time. For reasons of economy, practicality and space I used
the quartz halogen lamp. I want practical results even though I'm sure I
could get more precision with a specialized graphics arts printer. How many
darkroom workers actually have access to high-end printers, or the space for
them? I'm using a source that is accessible, relatively inexpensive,
portable, and doesn't have a large footprint.
Joe
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