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  1. #11

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    The Kodak literature makes a point about the thermometer being accurate to 1/4 degree F. My experience is that that is overkill for most work, and about 1 degree works for the average user. Most of the dial thermometers sold for color work are well within this tolerance.

  2. #12

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    Does this apply to both scanning and printing?

    I ask as I print my negs and I'm concerned by allowing temp to deviate by one degree I'll have a nightmare trying to balance colour.
    Steve.

  3. #13
    osprey48's Avatar
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    Thanks for the info. Firstcall photographic do a digital probe type for about £12, which is all I'd want to pay anyway, so I'll test it against my spirit one.According to what I've been reading about C41, a half or even 1 degree variation isn't that disastrous for an amateur hobbyist like me anyway, so I'll give it a go and adjust my times and temps as I get more experience.

  4. #14

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    I calibrate a 3 inch Weston Miroband against a Kodak Process Thermometer Type 3. The Kodak thermometer is great, but too fragile for everyday use. (Nor do you really want to break a mercury thermometer in today's environmentally conscious world.) Now, I only do B&W with it right now, although I did do one roll of C-22.

  5. #15

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    I use an instant read food thermometer that I got at a restaurant supply house. Its good to .1F and they adjusted and calibrated it for me. It cost me $20. For my water bath, I use a standard probe thermometer, $10 at IKEA.

  6. #16
    Mike Wilde's Avatar
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    My reference thermometer is a scientific type mercury thermometer in plastic coated glass. I picked it up at a liqidation auction with about 10 other (some broken) thermometers for about $20. It is about 2' long and goes from -10 to 100F in easily read half degree increments. It comes out perhaps once per month to fine tune or verify offsets for the other more pedestrian themometers in my different process equipment.
    my real name, imagine that.

  7. #17

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    I know there are some tolerance issues but I have seen no problems resulting from using these thermometers. I do small tank developing with the associated inherent inaccuracies. Varying elapsed time to pour developer out of the tank between two rolls and one roll, varying time to get the bleach in the tank, change in temperature when agitating outside the bath, etc....... This is a hobby for me. I try to be as accurate as I can but I don't use densitometers to check results. From a visual standpoint I see no problems in my film that I can attribute to thermometer issues. I check against a medical thermometer and apply the correction then enjoy the process and results. You can check out some of my results here.

    http://www.lamarlamb.com/On-Film



    Quote Originally Posted by perkeleellinen View Post
    A question for those of you using household thermometers for C41: how do you hold the developer to +/- 0.15C? Household thermometers I've seen are usually +/- 1C. Have those of you with less accurate thermometers found these tolerances are unnecessarily tight?

  8. #18
    Tony-S's Avatar
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    OK, so is there a link to a thermometer that is relatively inexpensive and calibrated out of the box?

  9. #19
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    Patterson certified mercury colour thermometer, they are guaranteed to be accurate to + or- 0.3 degrees C. straight out of the box.
    Last edited by benjiboy; 05-04-2012 at 10:48 AM. Click to view previous post history.
    Ben

  10. #20
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    There is one type of a cheap "household" thermometer that meters just perfectly at 100F/37.8C, because they are designed just for that close range and calibrated to high precision; if they were not, people would notice that soon in their intended use. They can be mercury type or, most usually today, digital. The digital ones are usually waterproof, too.

    You have to guess what it is. You probably have one.

    I have compared three of those, from different decades, and found they were all +/- 0.05 deg C compared to each other. Yes, 0.05, not 0.5.

    And, usually people have experience in using those so you will know it will show at least about correctly, without depending on any "certified by company X that makes most of its profit by selling low-quality overpriced plastic jugs to photographers" claims .

    Just buy an extra one and compare it to your existing one.
    Last edited by hrst; 05-04-2012 at 01:04 PM. Click to view previous post history.

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