Pyrocat M stain issue

[esearing]

I have been using Pyrocat-Metol for a couple of years now with fairly predictable results. But recently I pulled a pair of FP4 negatives from the SP445 tank that looked under developed but still had detail. When I printed one of the images it had areas of dullness and sharpness. When I examined the negative more closely it appeared the stain was merely floating on top of the image. I washed it again but it just got worse. I threw it in the fixer tray for 10 minutes and there the stain got soft again and I was able to remove it under running water. The resulting negative still has some stain but looks underdeveloped but has more contrast than I expected.

Any guesses why this one batch had an issue? What is my likely mistake?
The other 5 batches I processed came out fine using same chemistry and similar tanks.

[Andrew O'Neill]

Is there anyway you can show a scan of the negative?

[esearing]

I have already removed the layer of stain by refixing so can't show the effect. Below is a snapshot of the batches drying - you can see that two of them are much lighter than my usual density. When dry the negative did not look splotchy unless you held it at an angle to the light. I am guessing something was amiss. Maybe not enough part B or A was not shaken well enough or even maybe the tank was not clean enough and caused some interaction. I may try to bleach and redevelop just to see if it improves anything but its already so contrasty I doubt it will add any value to the image. Its an easy shot to retake so will likely just go make another.

If you look at the far right negative at the top you can see what looks like finger prints and a lighter stain area. Everything below that is what washed out.