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Reciprocity failure is a big problem for me (not just the spelling), so I have been looking at what manufacturers say about their products. At https://imaging.kodakalaris.com/site...f4017_TriX.pdf, I came across a very odd graph:
Attachment 207428
What does it all mean?
Hunt around for one that does have the actual numbers on it. I have one taped in my field notebook. These are graphs that suggest how to take what your metered exposure is and then compare to what is longer (sometimes MUCH longer) and should get you to good exposure accounting for reciprocity failure. Cutting back development time a bit helps too. Using TMAX 100 instead of Tri-x in such situations makes it a lot easier as far less adjustment is needed. TMAX becomes, in effect, a much faster film in low light if you're talking about time on "T."
Nelari
I checked the Kodak site and it comes up gibberish as you experienced. I believe it is supposed to be this one, which is self explanatory:
https://duckduckgo.com/?q=kodak+tri-...ge001_7514.gif
OK - thank you! I shall certainly try the TMAX 100 that you suggested. I really dislike reciprocity failure. And Fuji Acros is uncomfortably expensive.Quote:
Originally Posted by Kevin Crisp
Exposures that would require quite a bit of adjustment with Tri-x require none with the TM.
See:
https://imaging.kodakalaris.com/site...6_tmax_100.pdf
I found for my landscape work in 5x4 with Tri-X that I routinely had exposures around 1/4s. This meant with Tri-X that I was right on the edge of reciprocity failure in my shadows (Zone III). Try as I might I couldn't get consistent results; one time I'd get detail in my shadow, the next the shadows would be blank. Finally, after months of ignoring the urging I was getting to try TMY from this forum (yeah, yeah, I know, I know), I bought a box. Boom. Problem solved. I never finished the remaining sheets in the Tri-X box.Quote:
Originally Posted by Nelari
But that's not all that TMY did for me. Not only was it considerably more predictable in returning shadow detail, it was also more linear (short toe). I also found it to be more linear in the highlights. But the kicker for me was the tones that TMY rendered from the scene were a better match to what I was seeing in my head while looking at the composition on the ground glass. It just mapped better from color to B&W for me. Actually, a lot better. I was able to substantially reduce the manipulations I was making to get the print that I wanted.
I grew up with Tri-X. Probably have like 30 years of Tri-X experience. I knew Tri-X inside out. So I did not let Tri-X go easily. I really had to talk myself into learning another film. But just a few sheets of TMY had me thinking I'd never go back. And I never have.
People think I'm joking when I say that TMY is the finest film ever made. But I mean it.
I finally succeeded in scanning my first TMAX100 images - and am impressed. This one was shot under a railway bridge with my homemade roll-film pinhole camera: Attachment 207961The aperture is about 250, so the exposure was longish, 20 minutes (10 minutes multiplied by two for reciprocity failure.) Remarkably, there was no need to "correct" brightness or contrast or anything on the computer. (Development was Rodinal 1+50, 18min.)
This is as good as my images get. The other films I have tried do not come even close.
It is not about liking or not liking RF. All films have RF after some exposure time. J suggest to get an good app or use a calculator.Quote:
Originally Posted by Nelari
RF is a property of all film emultions. RF means that the linearity between exposure time and apperture does not apply anymore. You need a correction factor for the metered exposure time, so that
Tc= Tm^p
Where Tc is the corrected exposure time. Tm is the metered exposure time. P is the exponen of the power law proposed by Schwarzschild. This exponent has to be found by sencitometer experts. Ilford publish the exponent for their films. For other you find in the internet and experienced photographers has their own correction tables. RF is aplicable for a given emulsion, with time the components of rhe emulsions chance and so do the RF exponent p.
At the moment I an searching for a good and recent correction for TXP-320. I found one in Bruce Barnbaum book. I put the numbers into Reciprocity + app and give a try… it is easy. It us fun.