PMK Pyro and Clear negatives

[johnm]

Hi, I just started using PMK pyro to develop some 4x5 FP4+ and I'm running into some strange issues. So far, 4 out of 18 negatives have come out completely clear. One of them had a partial image in the lower left corner. All of the other negatives have come out great and the bad ones will be right next to the good ones in the mod54 in a Patterson tank. I'm using water for a stop bath and tf4 fixer. Keep in mind that perfect negatives (in my limited judgement at least ;) ) are in the same tank as the bad ones, so I wouldn't think it's a chemistry issue. It could absolutely be exposure issues,not removing the darkslide, etc.... I guess I'm wondering if anyone has had this issue with PMK Pyro, or if it is most likely on the pre development end. The film was all used on the big island of Hawaii, but it wasn't very humid and the bad negatives seem to be randomly mixed from rainy days to dry days. Was I just being dumb, or can PMK cause this issue. Thanks!

[jp]

Never seen pmk cause this. Sorry

[hmf]

If you've got good negatives right next to completely clear when they are processed together, logic suggests that some were never exposed to light. I vote for "not removing the darkslide". Or perhaps your shutter didn't open, or you kept the lens cap on, or you never turned the film holder over to even attempt an exposure on the second side.
If you are new to the large format game, where there are many opportunities for screw-up (I believe I've tried most), you might want to consider a checklist as a reminder to follow through on each step. At the very least, carry a small notebook detailing the holder number and the exposure conditions for each side/sheet.
Good luck.

[koraks]

If good and bad negatives were in the same tank of developer, then it seems extremely unlikely that the developer is the cause. I'd direct my attention to other factors.

[bob carnie]

Operator error... happens all the time.. PMK does have its strange habits , but this is not one of them.

probably darkslide issues.

[rjphil]

If the good negs were exposed first, I would check your shutter for proper operation.

[johnm]

I guess this confirms my suspicions, Operator error! Usually Im quite consistent in my workflow, but I think I felt the pressure of family waiting for me to compose, meter, and shoot, and for the rain clouds to pass by etc.... I guess large format is about taking your time.... :rolleyes: Thanks for the quick answers!

[mikew]

I guess this confirms my suspicions, Operator error! Usually Im quite consistent in my workflow, but I think I felt the pressure of family waiting for me to compose, meter, and shoot, and for the rain clouds to pass by etc.... I guess large format is about taking your time.... :rolleyes: Thanks for the quick answers!

It's really tough to work quickly with large format photography. I have the short term memory of a squirrel as it is, never mind trying to remember the details of each exposure that I make. So I always record my exposures in a journal with notes and a sketch, and number my slides for processing reference. It really helps when there are weeks or months between exposure and processing due to travelling, especially if there's a defect concern.

Best of luck.

Mike