Yesterday I developed two rolls of 120 HP5 in my stainless steel tank. I've developed hundreds of films, but hardly ever had the problem I had yesterday. The top roll had a partially undeveloped strip at the top. I should have realised what had happened as the sloshing sound was different. I even re-checked the volume required to cover both reels - I use 850 ml and that is just right, halfway between the top of the top reel and the top of the tank. Then I realised what had happened. The reason the sloshing sounded different was that the top reel must have got caught by the spring clip at the top of the rod. I tried to replicate that, and it is quite easy to do. Now I've made a mental note to myself to check that each time.
