I do the BTZS test, so I dont load holders to test, neverthless I thought of the same thing, the batch being notched the wrong way. I checked and it was notched correctly. I am now in the process of testing the 12x20 sheet which is supposedly done from a different batch than the 8x10 box. If it comes out differently then the 8x10 box was messed up, if not then JandC 400 film is not for me, I trust my testing methods and I had just tested a new box of Tmx 400 which came out fine.

Quote Originally Posted by Donald Qualls View Post
Just to eliminate the silly stuff -- that sounds awfully similar to results I read about a photography student getting some years ago when testing Tri-X (the ISO 320 sheet version): EI 16. What eventually turned out to be the case was that he was loading it backward in the holders, and exposing through the antihalation layer resulted in loss of about 4.5 stops of speed.

Now, I presume, Jorge, that you aren't making that mistake (especially not with enough sheets to get completely through a test series) -- but I can easily see how a batch of film could have gotten notched on the wrong corner, i.e. upside down when the notches were cut. Shouldn't be terribly hard to check to be sure the emulsion is on the correct side on some of the developed negatives (which wouldn't even require sacrificing a sheet to look for the light and dark sides)...