From: Sandy King (sanking@clemson.edu)
Date: 10/30/02-10:25:17 AM Z
There is a reciprocity correction chart for Kodak, Agfa, Ilford and
Polaroid B&W films on p. 75 of Simmon's Using the View Camera.
Nothing on Fuji.
Most Kodak films, especially the old emulsions such as TRIx-X and
PLUS-X, show more reciprocity failure than Agfa, Fuji and Ilford
films. On the other hand, T-MAX 100 is much better in this respect
than other Kodak films and can be considered reciprocity free until
exposures become longer than about 3-4 seconds.
The reciprocity corrections recommended by Simmons are very close to
the corrections that I use in practice when working with Kodak TRI-X,
Ilford HP5+ and Ilford FP5+. For example, two days ago I made some
12X20 negatives late in the afternoon on a very overcast day (SBR of
about 5.5). Exposure without correction indicated 2 seconds at f/64.
I actually exposed for eight seconds at f/64 and reduced development
time by 20%. The negatives turned out very nice but could have stood
just a tad less exposure and somewhat longer development. Had I used
the corrections recommended by Simmons I would have exposed for 4
seconds and used my normal development time for this SBR, and the
negatives would most likely have been even better.
Sandy King
> > Don, I've always assumed that compensation for reciprocity depended on
>> the
>> film. Does the Sexton data account for this, or has he devised a generic
>> that applies to any film? Do you suppose you send a copy of your
>> spreadsheet
>> to me as well?
>>
>> Mike Healy
>
>You are right. It isn't possible to develop a generic approach. One
>feature of recent Fuji films is that they allow quite long exposures
>without noticeable reciprocity failure - far superior to Kodak products in
>this respect.
>
>Best wishes
>
>Peter Marshall
>Photography Guide at About http://photography.about.com/
>email: photography.guide@about.com
>_________________________________________________________________
>My London Diary http://mylondondiary.co.uk/
>London's Industrial Heritage: http://petermarshallphotos.co.uk/
>The Buildings of London etc: http://londonphotographs.co.uk/
>and elsewhere......
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