I'm not sure if Foma and Efke PL25 are the same thing because I'm hearing different anecdotal info on reciprocity failure from different people.
Using the recommendations posted on J&C's site, I do what I usually do...I take the recommendations and make myself a curve fit equation so I can interpolate for a bunch of reasons, pinhole primarily, so the high end of the reciprocity failure is the more important part for me.
This film is one of the more uncooperative ones for finding a curve. It seems to take a uncharacteristic swing between 10 and 100 seconds that makes it difficult (impossible so far for me) to predict a trend and extrapolate to longer times.
Even the other film J&C had that needed 4 stops correction at 100 seconds was more predictable (a trend was evident and consistent across the time range given).
Then I hear some people have difficulty getting normal density with long exposures on this film.
For now, I am going to assume I just haven't cracked the reciprocity failure Sudoku puzzle on this one, and not assume there is an error in the published data. It acts like a film with fairly little reciprocity failure below 10 seconds then acts like a typical 'old style' medium-fast b/w film at longer times, but has a large 'jump' in between.
I would like to know what the experience of users (in use) is with this film at long exposure times (> or >>10 seconds.)
Thank you
Using the recommendations posted on J&C's site, I do what I usually do...I take the recommendations and make myself a curve fit equation so I can interpolate for a bunch of reasons, pinhole primarily, so the high end of the reciprocity failure is the more important part for me.
This film is one of the more uncooperative ones for finding a curve. It seems to take a uncharacteristic swing between 10 and 100 seconds that makes it difficult (impossible so far for me) to predict a trend and extrapolate to longer times.
Even the other film J&C had that needed 4 stops correction at 100 seconds was more predictable (a trend was evident and consistent across the time range given).
Then I hear some people have difficulty getting normal density with long exposures on this film.
For now, I am going to assume I just haven't cracked the reciprocity failure Sudoku puzzle on this one, and not assume there is an error in the published data. It acts like a film with fairly little reciprocity failure below 10 seconds then acts like a typical 'old style' medium-fast b/w film at longer times, but has a large 'jump' in between.
I would like to know what the experience of users (in use) is with this film at long exposure times (> or >>10 seconds.)
Thank you