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Go Back   APUG > APUG English Forums > Darkroom > B&W: Film, Paper, Chemistry > B&W film reciprocity calculations

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Old 05-16-2008, 07:21 PM   #21 (permalink)
 
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Default B&W film reciprocity calcs.

Hello Ian:Thanks for the suggestion.I'll get to downloading the sheets tomorrow.Didn't it used to be simpler when film manufacturers supplied such info with the film !!!.

Doug
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Old 05-16-2008, 07:28 PM   #22 (permalink)
 
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Default B&W film reciprocity calcs.

Hello:To all who replied to my question regarding B&W film reciprocity calcs.,Thank you for all your insights.I will try each method and suggestion when I have time.

Doug
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Old 05-16-2008, 07:35 PM   #23 (permalink)
 
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Hi Rob: Thanks for this info.It's a simple and understandable solution to this problem.Next time I'm shooting at night.I'll do a test roll and see how it turns out

Doug
Good Luck with it. If you find using this method that your shadows are blocked up too much, you will need a softer negative in which case reduce film speed by 2/3 stop(to give extra exposure) and also reduce dev time by 30% (to give less film contrast) and try again. But I bet that the first time you try it, you will nail the highlights.
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Old 05-16-2008, 07:53 PM   #24 (permalink)
 
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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
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Old 05-16-2008, 09:13 PM   #25 (permalink)
 
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Hi Ray:I shoot buses,streetcars and trains at night and I find that my usual films of choice,plus-x,t-max 400 1st.edition and hp5+ seem to have either not enough contrast,as with plus-x or too much contrast as with hp5+ or tmax 400 1st. ed.I've tried adjusting development times and dilutions but nothing seems to give me what I'm looking for.Relatively even contrast,with detail in the shoadows and highlights.My developer of choice is Rodinal for plus-x@1:50 dilution,same for tmax400,and D-76 1:1 for hp5+.

Any suggestions?.

Doug
I'd say right off the bat, that Rodinal is probably at least partially to blame. It's not very good at holding shadow detail, and you are working under challenging conditions. I've always been more than happy with Plus-X and D-76. XTOL will help even more with the shadow details and will hold the highlights in check. I find that this is even more applicable to TMax 400. Since you are already using D-76, give that a try next time and see if you don't get an improvement with these two films. Next time you're restocking chemistry, pick up some XTOL and give it a go. It works very well with HP5+ too.
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Old 05-17-2008, 03:45 PM   #26 (permalink)
 
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Quote:
Originally Posted by Murray@uptowngallery View Post
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
Look in www.unblinkingeye.com for LIRF. You should find my analysis of Bond's data.
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Old 05-17-2008, 05:48 PM   #27 (permalink)
 
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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
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Old 05-18-2008, 12:11 AM   #28 (permalink)
 
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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.
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