A few days back I was printing in the school's darkroom on Ilford MG-RC. I was getting dark gray streaks and spots on almost every print. The marks were apparent as soon the print was out of the wash and where at random places on different prints. Some prints had more than others.
I then eralized that the print had those marks as soon as it was out of the developer (Ilford PQ). I mixed the developer fresh and was definitely far from exhausting the dev. I did notice that the bottom of the tray was kinda blackish. The tray was washed thouroughly before the printing session started.
Any ideas what this might be ? I've been printing for some years now and this is the first time that I see this.