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  1. #1

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    Water temperature

    Probably hear lots of this, but I've been guessing my water temperature for a while now, always leaning towards what my body feels is lukewarm.

    Recently I bought a glass thermometer to standardize my process and keep it consistent. It sits at 78F when just laying around and only goes to 68F if throw it in nothing but colder water from my tap. Anything other than straight cold water from the tap puts it at 80F or higher.

    I developed a roll with it and it seemed far underdeveloped. Is it possible that my thermometer is just wrong?

  2. #2
    Newt_on_Swings's Avatar
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    Water temperature

    Drop it in a glass of ice water and then a pot of boiling water. Give it a bit of time so there is no thermal shock to break the glass though. Check both temps.

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    Re: Water temperature

    Quote Originally Posted by Newt_on_Swings View Post
    Drop it in a glass of ice water and then a pot of boiling water. Give it a bit of time so there is no thermal shock to break the glass though. Check both temps.
    What temperatures should I get from both of them?

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    A thermometer is one of the pieces of equipment that you will always need and the right temp is crucial enough not to rely on just any thermometer. If I have understood your description of your thermometer it sounds unreliable. Buy a photographic thermometer certified accurate to within 0.2 degrees centigrade

    They aren't that expensive( and a lot cheaper than ruining film development) and will last a lifetime. I am sure you will feel it is too dangerous to guess quantities of liquids and use proper beakers calibrated for ccs or fluid ozs so why not eliminate guesswork when it comes to temperature as well

    pentaxuser

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    Quote Originally Posted by Newt_on_Swings View Post
    Drop it in a glass of ice water and then a pot of boiling water.
    Boiling points are dependent on altitude or current atmospheric pressure and are not accurate unless you make the appropriate correction. At 5,000 feet water boils at 203 F.
    Last edited by Gerald C Koch; 10-02-2012 at 10:20 AM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

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    I'd be surprised if what your body feels is lukewarm is low enough. Your body temperature is 98F, so 68F is going to feel quite cold.

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    Rick A's Avatar
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    Quote Originally Posted by mcgrattan View Post
    I'd be surprised if what your body feels is lukewarm is low enough. Your body temperature is 98F, so 68F is going to feel quite cold.
    Absolutly-- 68 feels downright cold.
    The OP definitly needs to invest in a quality thermometer.
    Rick A
    Argentum aevum
    BTW: the big kid in my avatar is my hero, my son, who proudly serves us in the Navy. "SALUTE"

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    Human sense of temperature can be fooled very easily and is very unreliable. As it stands, you have no standard to go by....

    If you are at all serious about getting good results from your film processing, you should buy one you can trust. There is no need to go overboard and get a NIST certified meter. 20 to 30 dollar kind from photo stores are just fine.
    Develop, stop, fix.... wait.... where's my film?

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    I taught a class in physical chemistry. One of the experiemnts was the Carnot cycle of a rubber band. The most sensitive part of the human body to gauge temperature is on the underside of the lower lip. This spot was used by the students to see if the rubber band got cooler or hotter. If you stretch the band it gets warmer when you relax the band it gets cooler. Stretching the band forces the rubber molecules to become aligned with each other. This reduces the entropy releasing heat. When relaxed the molecules become randomized which requires the absorption of heat and the band gets cooler. To try this out you need a rubber band that is at least 1/4 inch wide.
    Last edited by Gerald C Koch; 10-02-2012 at 12:16 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  10. #10
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    The body is very good at detecting changes in our surroundings, like temperature, humidity, etc. We know very rapidly that there is a change.
    However, and this is a big deal, we are terrible at telling how much with any sort of consistency. This is why very smart people invented things like thermometers.

    Buy a good thermometer, and develop your film at the same temperature - every time. Unless you don't care about the end results.
    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

    "...the heart and mind are the true lens of the camera". - Yousuf Karsh

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