My thermometer is 5 degrees...warm!

Discussion in 'Darkroom Equipment' started by david b, Oct 21, 2006.

  1. david b

    david b Member

    Messages:
    4,031
    Joined:
    Oct 20, 2003
    Location:
    None of your
    Shooter:
    Medium Format
    I just picked up a car load of darkroom from a garage sale and included was a like new thermometer, just like the one I consider to be my "trusty" thermometer.

    So, I put the new one in a beaker filled with water to compare against my "trusty" thermometer.

    Well, it registered about 5 degrees colder than 'ol trusty.

    Okay, so I put in 3 others including a glass Delta 1 thermometer.

    Guess what? 'Ol trusty is 5 degrees warm, meaning the developer temperature is really 63 when I thought it was 68.

    Frack!!!!

    Do yourselves a huge favor and double check your "ol trusty".
     
  2. zenrhino

    zenrhino Member

    Messages:
    697
    Joined:
    Nov 20, 2004
    Location:
    Minneapolis,
    Shooter:
    Medium Format
    If you use the "instant read"-type stick thermometers that you can get at restaurant/kitchen supply places, they are easy to calibrate:

    Check to see what temp water boils at given your altitude. Put some water on to boil. Put your stick (thermometer) in the water and write down the result. (should be right near your boiling point)

    Next, get some crushed ice (a great excuse to get a sno-cone or a coke from Hardees) and mix a slurry of that and water. Put your stick in the water and write down the result. (should be right near 32deg F)

    Instant read sticks calibrate using a nut on the back of the reading head. Use a pair of needle-nose pliers or something similar. Be sure to check it again after calibrating at the high and low end because these sticks tend to be non-linear.

    Of course, you can avoid the whole thing by spending $12 on one of those combination timer/digital thermometers from Target. Wish I'd have had one of those in culinary school. Can't tell you how many times I had to calibrate sticks or how many electronic sticks I'd dropped into something.
     
  3. rjas

    rjas Member

    Messages:
    227
    Joined:
    Jan 4, 2006
    Shooter:
    Medium Format
    for black and white, does it really matter as long as your 20 degrees is the only 20 degrees you use? The kodak thermomter i use reads at 20 degrees while the cheapie food thermometer i have laying around reads 16 degrees at the same temp. its never bothered me and i dont really care if its actually 24 degrees or 20 degrees or 16 degrees as long as thats the same temp i use all the time.

    i could see it as a problem if you broke your thermometer and had to buy a new one but even then i dont think a good thermometer from kodak would vary by more than a degree but i just prefer not to think of these things rather than worry about them. chances are ill never notice...
     
  4. Claire Senft

    Claire Senft Member

    Messages:
    3,242
    Joined:
    Dec 7, 2004
    Location:
    Milwaukee, W
    Shooter:
    35mm
    With 5 thermometers you have an increased chance that one of them will tell you the temp. is just right..no need to warm or cool solutions.