B&W film reciprocity calculations

Murray@uptowngallery said:

I went looking for the mkaz site. Thanks for re-listing it.

There was also a mkirwan site with some collected data. I think it included the Gainer-Bond data in a graph or spreadsheet, possibly additional film data, but couldn't get to it (dead link).

Anyone know if he still has a site?

Thanks

Murray

Click to expand...

Look in www.unblinkingeye.com for LIRF. You should find my analysis of Bond's data.

The Bond test data and conclusions are in Photo Techniques, Jul/Aug 2003, Vol. 24 No. 4. The back issue is still available from the magazine's web site.

Films tested were HP5+, Tri-X, Ilford 100 Delta, TMX, and TMY. Tests were done to find adjusted times needed for 1 second to 240 seconds of metered exposure. It's a good article with the adjustment results for each film listed at 1/3 stop intervals. At minimum TMY has had one revision since 2003.

Lee

My follow-up was in the next issue, September-October. The interesting thing to me was that the curves on log-log paper were straight lines, with some random-appearing scatter, that were parallel for all the films tested. The fact that HP5+, 100Delta, Tri-X, TMY and TMX had the same slope but different intercepts gives some confidence, to me at least, that one reliable test at long exposure time will be sufficient to establish the LIRF effects of any new film.