Thermometer Thoughts & Choices

craigclu · Jan 30, 2019

A few years back, America's Test Kitchen reviewed and picked some Thermoworks products as standing out from the pack. When a good sale hit my email, I bought a basic rig from them and have enjoyed using it for tight controls in the kitchen for yogurt making, meat cooking, beer brewing and tuning brew temps on my espresso gear. It's easy to check calibration and is confidence inspiring in general use. I bought my son a version one Christmas with a remote neck lanyard for smoking and slow cooking outdoors without needing to monitor so closely at the grill and he's loving it (while not being a gadget freak). I see they now have Bluetooth/Smartphone gear, too.

I've been fine with glass/mercury/alcohol lab thermometers in the darkroom but when playing with the chambers in a Nova processor I tested yesterday, I pulled out my digital rig and realized how handy it could be in the darkroom. It also has a timer built in and could make for a nice assistant in the darkroom. They make multi-channel rigs and quite an array of options/probes/features that could adapt well to photo duties. They seem to function in the mid-price range between the disposable cheapies and the lab grade professional gear. Their site is at: https://www.thermoworks.com/

The basic rig I'm using is this one:

MattKing · Jan 30, 2019

I use something similar on a regular basis.
I confirm its readings regularly by checking it against my calibration standard, a Kodak Process Thermometer.

ic-racer · Jan 30, 2019

I use glass thermometers. They are smaller than the electronic ones, waterproof, and don't rely on batteries.

Having mentioned that, I did check out the link and they have great variety; a thermometer for every darkroom need. I found this that would work for me. Waterproof and 5000 hour battery life.

BMbikerider · Jan 30, 2019

For preference I would always choose Mercury type but sadly they are no longer sold. I still have one which must be at least 20 years old and is a certified type +/- .25 degree and is as accurate now as it was when new. I also have a Kodak process thermometer which is at least 10 years older and showing it's age. It is still accurate as both agree with each other but the Kodak one is now very slow getting to the final temperature.

The 'stick' type with the dial on top are OK for B&W printing but wouldn't trust one when processing C41. Likewise the spirit type similar to the Mercury but are nowhere as accurate and the are in the same category as the dial type.

R.Gould · Jan 30, 2019

I use something similer to the OP, a digital thermpmeter from Firstcall Photographic, very accurate and easy to use

Alan9940 · Jan 30, 2019

I have a few different types/styles of thermometers, but only use those that match my standard: Kodak Process Thermometer.

Chan Tran · Jan 30, 2019

I use the Kodak Process Thermometer too for processing. For cooking I have a very fast electronic thermometer but I don't think its as accurate as the Kodak. I have several Fluke thermometer I use for work. I don't think they are accurate enough for processing.

Saganich · Jan 30, 2019

I work in research labs during the day and over the years have collected about 10 thermometers that were standards for lab work. None give the same reading on any given day. The only rational thing to do is average them together to use as a correction factor of the one you use regularly.

guangong · Jan 30, 2019

I also use Kodak process thermometer. Have had it for decades. Also use a dial thermometer marketed by Omega. Have had that for decades also. Both accurate and read the same.

mgb74 · Jan 31, 2019

I have found that the cheapie thermometer from Thermoworks is so good that it's hard for me to justify the more expensive ones. I regularly compare mine to my Kodak process thermometer and find it's always well within 0.5 deg F. It's not as fast reading as some of the others, but that not an issue.

DREW WILEY · Feb 9, 2019

There was a specialty thermometer dealer for many years in town who served both the University and the numerous biotech and pharmaceutical R&D labs around here, plus the big Fed atomic labs. Had thousands of thermometer in inventory. And yes, you can get accurate highly reliable scientific thermometers. But the point is to find them calibrated to the specific temperature range typical of photographic processes. I too highly recommend the later version of the Kodak Process thermometer. Faster reading and less fuss than electronic ones. They can still be found, generally used. But you could also substitute comparably priced glass thermometers with the same calibration range from lab suppliers like LSS. Usually in the $250 range - a distinct temptation to find a clean used Kodak version instead, typically around $50. Don't confuse these with their cheaper versions. I've worked with certain film applications where the dev temp had to be kept within 1/10 def F. No problem. Used an expensive recirculating thermoregulator and that good old Process Thermometer. But that kind of temp nitpickiness is overkill for most photographic applications. I see no reason why a dedicated good photo thermometer shouldn't last a lifetime. These Process Thermometer have a tough stainless steel sheath. And they logically don't get plunged into boiling water or strong reagents like some lab applications, or otherwise tortured. Don't loan one to a student or klutz. They're designed to do one thing well, within limited temperature parameters.

mshchem · Feb 9, 2019

You need at least one thermometer like a Kodak process thermometer that's actually been certified to a NIST (used to be NBS) standard I have a couple of KPT and a couple lab thermometers . I use these to check and occasionally calibrate nice dial thermometers. I have found some digital lcd display aquarium thermometers on ebay 2 or 3 bucks a piece that agree astonishingly well with the process thermometers GIVEN TIME TO EQUILIBRATE . This may take 10 minutes. There's so much stuff out there. Taylor, made small stem glass spirit thermometers for Kodak rapid color processors, 75 to 105 F perfect for color work.

Deleted member 88956 · Feb 10, 2019

Kodak Process has always been my choice (and still can be had today for $40-50 with some patience) ... until I had found DT-1. For those in Europe it's an easy purchase, fast response, super high accuracy, can be ordered with calibration certificate. They also make an inexpensive wall bracket, which comes handy in a darkroom, so you can have a bracket in several convenient locations and stow the meter where you need it for use.

The meter shown in original post looks promising, perhaps a bit too much built ino it for me. For some reason I'm away from all-in-ones as I often find these things good on paper but not so great in actual use when all extras were considered at purchase, only to realize the extras when use make it too much to think of.

jim10219 · Feb 10, 2019

I have some nice mercury thermometers, but I primarily use a cheap cooking thermometer. As long as it's consistent, I don't care much if it's accurate. I use my own temperatures and times based on my own experiences. So long as the results are repeatable, I'm happy.

Deleted member 88956 · Feb 10, 2019

Chan Tran said:
I use the Kodak Process Thermometer too for processing. For cooking I have a very fast electronic thermometer but I don't think its as accurate as the Kodak. I have several Fluke thermometer I use for work. I don't think they are accurate enough for processing.

Never checked the site linked in original post before posting and this I fully agree with. Getting one that matches time tested Kodak can certainly happen, but will it maintain it? What happens when one you get does not match needed accuracy? Return, get another sample? The DT-1 I linked earlier is a killer device for the money and comes with actual guarantees of accuracy.

The thing is that I had bought a watch at WalMart in early 2000's for $15. It maintained few second accuracy for several years until battery died and I never bothered replacing with new. Same brand for twice the money bought few years later was not even close.

John51 · Feb 10, 2019

jim10219 said:
I have some nice mercury thermometers, but I primarily use a cheap cooking thermometer. As long as it's consistent, I don't care much if it's accurate. I use my own temperatures and times based on my own experiences. So long as the results are repeatable, I'm happy.

I use a meat thermometer. I've got 2 of them and the readings match.

As a meat thermometer, it goes for ~£3.50. If you want the same model for hydroponics, that's ~£8.50 but for photography, it's ~£12.50.

wahiba · Feb 10, 2019

For those of us this side of the pond the following link: https://thermometer.co.uk/oven-ther...m-professional-cooking-thermometer-timer.html has the same items for sale for £45 inc. VAT. Looks good. There is a lot lot more on the site that might be of interest too.

Chan Tran · Feb 10, 2019

Witold said:
Never checked the site linked in original post before posting and this I fully agree with. Getting one that matches time tested Kodak can certainly happen, but will it maintain it? What happens when one you get does not match needed accuracy? Return, get another sample? The DT-1 I linked earlier is a killer device for the money and comes with actual guarantees of accuracy.

The thing is that I had bought a watch at WalMart in early 2000's for $15. It maintained few second accuracy for several years until battery died and I never bothered replacing with new. Same brand for twice the money bought few years later was not even close.

What kind of accuracy do they warranty?

Deleted member 88956 · Feb 10, 2019

Chan Tran said:
What kind of accuracy do they warranty?

There is a link to the web site in my earlier post. With calibration certificate that in my case ran within 0.03 of C from reference I'd say accuracy is very high. 0.01 resolution also indicates quality behind it. After 2 years I have not seen any difference creep between 2 units I have. For the money equal to an uncalibrated fancy meat thermometer I'm quite comfortable what this device delivers.

Chan Tran · Feb 10, 2019

Witold said:
There is a link to the web site in my earlier post. With calibration certificate that in my case ran within 0.03 of C from reference I'd say accuracy is very high. 0.01 resolution also indicates quality behind it. After 2 years I have not seen any difference creep between 2 units I have. For the money equal to an uncalibrated fancy meat thermometer I'm quite comfortable what this device delivers.

The specs of the DT-1 is very impressive.

Deleted member 88956 · Feb 10, 2019

Chan Tran said:
The specs of the DT-1 is very impressive.

The most impressive one for me is the 5 second response time and it is indeed fast in use. With Kodak Process like with any other mercury thermometer, you have to wait to be sure. With some cheap electronic ones, you almost never know if it is steady or is it suddenly going to jump half a degree.

mklw1954 · Feb 18, 2019

I calibrate a couple of Extech TM20 digital thermometers with a wire probe, calibrated to a Paterson Colour Thermometer, and get great results doing color (use them for b&w as well). The Extech thermometer response time is not the greatest but it works.

Pentode · Feb 18, 2019

I have several mercury lab thermometers that I use for processing and an old dial type meat thermometer that I use for mixing powdered chemicals in hotter water.

Even though they all agree with each other I tend to stick with the same one for the developer just to keep things consistent.

Tim Stapp · Feb 19, 2019

I went to the local home brew/wine supply store and purchase mine. It agrees with the Kodak/JOBO one that came with my used CPE2+.

runswithsizzers · Feb 19, 2019

My Medium Format Photography class at the state university uses basic $20 Samigon dial thermometers for b&w film developing. At 68*F some read 1*F low and others 1*F high, but that's probably close enough for b&w.

When the time comes to get one for home, I will probably get the Weston Model 2265 dial ($37 from B&H <here>), or maybe the digital Thermoworks Super-Fast Pocket Thermometer ($30, <here>)

RE: Thermoworks
I have a pH meter and several air temp / humidity gauges from Thermoworks, as well as two cooking thermometers with probes. All good stuff and backed by good customer service (real humans in the USA answer the phone!)

Back in January when they had a big sale, I tried to find a thermometer for developing film. I was hoping for +/- 0.5C in case I decide to do E6 or C41 at some point in the future. Their website does not include "photography" or "darkroom" as search terms, and I was unable to seach their website by the accuracy spec. I quickly got tired of clicking on each of the dozens of different models to look at the accuracy specs one-by-one. Their phone line was having problems, so I sent an email inquiry asking for a recommendation. By the time I got an email reply the sale was over, so I gave up.

The funny thing is, back in January I was not able to find anything on their website said to be +/- 0.5C until well up into the $100-and-over range. But now I see Thermoworks has several thermometers from $30-40 with +/- 0.5C accuracy! Don't know if I just missed them before, or if Thermoworks has recently upgraded their specs on their lower priced models.

Wish I would have kept one of the mercury thermometers when the medical lab I worked in decided to eliminate mercury from the lab as much as possible. Except they did keep the NIST ref thermometer we used to check all the others.

Thermometer Thoughts & Choices

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