Having been impressed by forte's paper I recently decided to give their film a whirl. I shot several sheets of fortepan 400 over winter break to get acquainted with it.

Now I'm seeing a strange defect that I'm sure is my own fault, but I've never seen anything quite like it. These blotches that you can see all across the sky area of the attached images appear on the negative as areas of lesser density.

Experience tells me they're the shadow of bubbles during development. But this is the only defective negative out of a batch of six! The negative was developed in a combiplan daylight tank with my usual obsessive-compulsive sink rappings. Agitation was my usual 30 seconds + 10 sec/min inversion routine.

I always pre-rinse. Developer was Sprint 1:9, and I used photo formulary indicator stop, Russell Ready-Fix (w/ hardener added), heico permawash, and photo-flo/DI water mixed 1:200.

I've done other batches of fortepan 400 over the last few days in exactly the same manner, and no other negatives exhibit the blotches. So what could have gone wrong for this one?

Any comment appreciated by this APUG lurker.