From: John Cremati (johnjohnc@core.com)
Date: 12/22/01-12:55:26 PM Z
As stated from a previous recent thread ( copy is below) I had
read in "Photographic Emulsion
Technique" by T. Baker that dicromated treated colloids are most sensitive
to UV
between 350nm and 420nm range. You would want a light source that has a UV
output rating in that range... Most mercury vapor based lights I believe
will work......Some have mentioned that they use a halogen light source with
acceptable results.... I have yet to fully figure out how the wattage of
the bulb relates to the exposure outside of just knowing that the more
wattage out put means faster exposures.
I have been working with diazo sensitized silk screen emulsions for
years I have used a 220volt , 1200 watt , mercury vapor bulb that was
used for high indoor commercial lighting applications with fair
results....I had sold one of these bulbs to a friend who does albumen
printing and she claims it works just fine but she still uses sunlight to
expose with most of the time...
The commercial mercury vapor light puts out at a rating of 379 nm which
is the number I had gotten from the bulb distributor.... I have
recently purchased several high output Mercury vapor light sources
specifically designed for silk screen and UV exposure , one at 2000 watts
and another at 5000 watts but have yet to hook them up...... I know the
faster you can expose a silk screen, the sharper the screen will be..I am
now just getting interested in the alt-photo end so I do not yet know how or
if this applies but I am optimistic that it does...JC
>From Previous Thread:
This info is just great.. I had just read in "Photographic Emulsion
Technique" by T. Baker that dichromate colloids are most sensitive to UV
between 350nm and 420nm. I will definitely move ahead with the project of
building a high output UV enlarger..
----- Original Message -----
From: "Ed Stander" <glassact@compuserve.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Wednesday, December 12, 2001 6:05 PM
Subject: Re: Ultraviolet projection through El-Nikkor lenses - Real Data
> Folks:
> I put a relatively new El-Nikkor 210 lens in the path of my UV
> spectrophotometer today, and am happy to report that the lens passes
pretty
> well all UV radiation above 350 nm. In Comparison, my Fuji 300mm LF lens
> began to cut UV at around 400 nm, and showed strong absorption by 380 nm.
> This makes sense, as plain old plate glass shows similar trends. Cheers,
> Ed
----- Original Message -----
From: "Denise Sallee" <boann2000@yahoo.com>
To: <alt-photo-process-l@usask.ca>
Sent: Friday, December 21, 2001 9:34 PM
Subject: POP exposure light source?
> I am just beginning to use the POP process and have
> information from the Chicago Albumen Works. I do not
> want to use sunlight....are there any recommendations
> for an indoor source that is convenient and gives
> fairly consitent results? Does it have to be a UV
> light?
> Thank you for your help!
> Denise Sallee
> Pinhole Photographer
>
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