[pure-silver] Re: White Light
- From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Tue, 4 Jan 2005 05:56:09 -0800 (GMT-08:00)
-----Original Message-----
From: Chris Fraser <chris@xxxxxxxxx>
Sent: Jan 4, 2005 4:26 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] White Light
I have a 5x7 contact printer that has miniature frosted white incandescent
bulbs for the light source. I am aware that the unit should be used with
graded paper, but what would be the filter equivalent (if there is one) of
using this white light source with VC paper? I did do some tests (4"x5" PMK
neg) and the print appeared "muddy" so it is probably not feasible with VC
paper... I am just curious
Regards,
Chris
Muddy in what way? Do you mean overall low contrast or lack of detail in
some part of the gray scale, or blotchy?
VC filters are designed for incandescant light with a color temperature of
around 2900K to perhaps 3000K. The miniature lamps may be below this which
might lower the contrast of each filter somewhat but will not cause the radical
shift of a cold light enlarger head.
Regular VC filters can be used provided you can get large ones. They are
available but expensive.
Most contact printers have a sheet of diffusion glass under the clear glass
platen. If this is missing the light may be uneven. There should be a shelf or
slot or other support for it. Diffusing plastic works well if small lamps are
being used. If the prints look blotchy this is likely the cause.
The only contact speed paper left on the market is Kodak Azo. This is sold
by Michael Smith and Paula Chamlee: http://www.michaelandpaula.com
Unfortunately, its only available in two grades now.
Enlarging paper works fine for contact printing but the light must be cut
way down for it. Enlarging paper is on the order of 100 times as sensitive as
contact paper.
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
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