I have developed a 120 roll of FP4 in Pyrocat 1:1:100 for 16 minutes with 1 minute agitation followed by 1 inversion every minute. Stop bath was plain water for 30 seconds. When I scanned the negatives I noticed a strange mottled effect, like little white dots, in the sky in a couple of the negatives. You can see it clearly in the photo below. Any ideas what may have caused it?



