"Regular" optics do not fare well with UV, specialty ($$$) glass is required. As VDB, cyanotype, etc., are very slow processes compared to silver-gelatin, exposure times are very long. The Fresson lab in France does use an enlarged negative system, but exposures take hours even with an arc lamp, and the negatives get rather cooked in the process.
Luis Nadeau operates a Fresson Lab in Canada
Luis Nadeau
P.O. Box 221 Station A
Fredericton NB
Canada E3B 4Y9
Scott Macleay works in the Fresson Process another Canadian
www.scottmacleay.com
thanks I thought so what does AFAIK mean , I am over 60 and slow now
Why would it be easier more steps are necessary to make a copy negative than a direct enlargment. Also looking at the Pentacon example which was designed for chloride emulsions that were only sensitized for UV-light the exposure times using a 50w mercury vapour lamp as lightsource were not that long.
According to the linked source (german one in my previous post) around 30 to 50 seconds for Agfa Lupex lens at f4.5 x9 enlargment
Why would it be easier more steps are necessary to make a copy negative than a direct enlargment. Also looking at the Pentacon example which was designed for chloride emulsions that were only sensitized for UV-light the exposure times using a 50w mercury vapour lamp as lightsource were not that long.
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