Note about Kodak Tri-X Pan and Plus-X Pan: Kodak's published time for the new 400TX film in dilution B is 3 3/4 minutes at 68 F. That is too short to be practical, and I think they have made a serious mistake; it looks to me like the time for dilution A. I think they used the wrong dilution in their testing for both 400TX and 125PX.
Numerous photographers tell me that the correct time for 400TX is only a few percent shorter than for the old TX. Even Kodak told me the same thing – though they insist that they didn't mix up the dilutions.
However, it's generally agreed that Kodak's published time of 7.5 minutes for TX in dilution B was a bit long. Most photographers recommend about 6 to 7 minutes.
I want to thank Dick Dickerson and Silvia Zawadzki (retired from Kodak, part of the team that invented Xtol) for correspondence about this. They, too, think the wrong dilution was used in Kodak's tests. It will be interesting to see if the published time changes in future Kodak publications.