Rant: My darkroom thermometer gave up mid-develop last night

I was developing a roll of Tri-X 400 around 10pm and my old Kodak thermometer just stopped reading. Stuck at 68 degrees while the water bath was clearly hotter. Ruined the whole batch because I guessed on temperature. Has anyone else had a thermometer fail like that mid-session?

3 comments

3 Comments

joel_hall1710d ago

Start checking those thermometers against a known temp before each use... I had an old Paterson one drift on me mid session and ruined a roll of HP5. Now I always dunk it in the working solution for a minute and compare with a backup digital thermometer. Your Kodak one could have been fine but maybe the alcohol in the chemistry got to the glass, mine started reading low after years of developer fumes. Grabbed a cheap lab grade glass one from B&H for like fifteen bucks and keep two on hand now.

lily7010d ago

Read that Paterson thermometers have a known issue with the mercury separating after a while if they get knocked around. Could be the fumes did something to yours but I've also heard the liquid inside can just break apart from regular use. My dad was a lab tech back in the day and he always said you can check them by putting them in ice water and boiling water to see if they hit 0 and 100. I do that every six months or so on my old Kodak one and it's still dead on after fifteen years. But he also warned me those cheap glass ones from the 70s sometimes had impurities that made the readings shift over time. Might be worth testing yours in some known temp water before you risk another roll of film.

the_elizabeth10d ago

Damn, that's rough about the HP5 roll. I've been there with ruined negs and it stings every time. But wait, you said the glass thermometer started reading low after years of fumes - how long exactly had you been using that same one before you noticed the drift? I'm curious because I've got a couple old glass thermometers from the 90s I inherited and I keep wondering if they're still accurate after all these years. Did you catch the drift on a specific batch or did something just feel off about your development times?