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Darkroom thermometers

BlueWind

Member
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Aug 27, 2005
Messages
105
Location
Almada, Port
Format
35mm
Hello

My digital thermometer died recently (some parts of the battery compartment went loose).
I found advertisements for thermometers with an analog dial, without batteries (!) from sellers in China, at a low price.
Are these reliable and robust ??

I still have a mercury thermometer , so I am not in a hurry .

Grateful for any opinions

Joao
 
I am a fan of the Thermoworks products, Thermopen and Thermopop. They will give a reading a a few seconds, have nice long probs and are basically bullet proof.
 
I use an old school analog thermometer from Jobo. Not as instant as a digital thermometer but it seems pretty accurate and there's nothing electronic to fail.

3321 Color Thermometer

Quality, commitment, and professionalism have made JOBO one of the leading brands in the photographic industry since 1923. JOBO tanks and products have become legendary and JOBO's innovations set the standard for darkroom processing. Film processing requires careful control over temperature. A...
cinestillfilm.com
 
Similar question: I have a Bogen Adjustable Dial Thermometer that I love the look and feel of.

But I always have to adjust it. Is that typical or do I just have a bad one? It's OK today but I check it every session.
 
Bill Burk said:
Similar question: I have a Bogen Adjustable Dial Thermometer that I love the look and feel of.

But I always have to adjust it. Is that typical or do I just have a bad one? It's OK today but I check it every session.
Click to expand...

No experience with any Bogen thermometer, but I've used a Weston dial thermometer for 40+ years and have never adjusted it. I've never dropped it and I'm always a bit on the ginger side when using it. I check it every so often against a Kodak Process Thermometer that I know is accurate.
 
Mercury thermometers are acurate and simple in chemical/thermo relationship. Stick with mercury.
 
I have a good one I use as a reference but for darkroom work I like the Paterson thermometers. They're good enough and not too expensive so I have several of them. There are two sizes with different temperature ranges.

Thermometers – Paterson Photographic

patersonphotographic.com

 
I like my Paterson mercury thermometer, but I'm always afraid it might break while I'm juggling things.

I use ThermoPro digital thermometer for grill, but I'm not sure if they are accurate enough for darkroom. Some of the cheaper digital thermometers either have questionable accuracy or build quality.
 
The Kodak "Color Thermometer" is alcohol filled, so there isn't much danger if you drop it. And it is accurate. The Color thermometer, a Kodak Process thermometer, and a couple of laboratory thermometers all read with a fraction of a degree of each other.

As to cheap thermometers, if they are repeatable and if you have a known good thermometer to compare them to, accuracy is a moot point. If you know that when it reads 72F that it is really 68F, well, just develop film at 72F 'indicated;' Just like the speedometer in an analog car.
 
I use a cheap digital kitchen thermometer on a day to day basis, which I compare regularly against my Kodak Process Thermometer.
Works well for me, because it is reliable, inexpensive and easy to use.
Here is one with the same form factor:
 
I use the Kodak process thermometer for film and either of the others for print chemistry.
The Kodak, Beseler and Unicolour speak for themselves.
The larger thermostat came from an old electrical transformer.
I also have an old thermometer that has a dial tabulated in brail which is useful during power outages .


 
There is only one option as far as I'm concerned : the Kodak Process Thermometer Type III, a thermometer to check other thermometers against. And when it comes to cheaper ones, or electronic ones, what counts more than their degree accuracy is their consistency.

But one should be a little more respectful of mercury. If it weren't for mercury, there would have neither been Daguerrotypes, nor mad hatters, nor equally insane Daguerrotypists. Inspiration has to come from somewhere.
 
I apreciate your replies. Some useful information there.

"...It’s reasonable to try one of these cheap dial thermometers ..."

I will give it a try, comparing with the mercury thermometer in order to assess reliability and consistence . Concerning long time sturdiness, time will tell...

Thank you again

Joao
 
Bill Burk said:
Similar question: I have a Bogen Adjustable Dial Thermometer that I love the look and feel of.

But I always have to adjust it. Is that typical or do I just have a bad one? It's OK today but I check it every session.
Click to expand...

That reminds me I haven't checked my adjustable faucet thermometer in awhile. I have 4 12" non-mercury laboratory thermometers, which are rated +/- 1C. I set my faucet temp to 68F and put all four thermometers into a beaker and and get an average. The average was 19.25C (66.65F) without any outliers. I reset the faucet dial to 67... not bad for over a year.
 
Klaus Mähring said:
The old Ilford digital ones are quite good, and pop up on ebay quite often.


Click to expand...

I've been using one since late 1999, it came in a job lot of darkroom equipment.

While I have quite a few alcohol & mercury thermometers, it is just so much faster and more accurate using a digital thermometer.

Ian
 
DREW WILEY said:
An incorrect generalization, Ian.
Click to expand...

No, a personal observation from around 60 years of darkroom use. I still have the Paterson thermometer I bought in the mid 1960s, however I have lab grade calibrated thermometers that I used for many years, accurate to =/- 0.2ºC. So I cross-checked with the digital thermometer and they match.

One problem with accurate mercury thermometers is the care needed using them, the probe on a digital thermometer is robust, the digital display is way easier to read.

Ian
 
I found lab grade bulb thermometers not only much faster to achieve the reading than electronic ones, but more dependable. No batteries to worry about either. I wouldn't call anything Patterson lab grade, although they're probably fine for basic black and white work.

There was once an entire thermometer warehouse just a couple blocks from where I worked, serving both the University and all the pharmaceutical and biotech facilities springing up in the immediate neighborhood. The selection was incredible. But none of that was in the same league as some of the in-house "thermometers" designed up on the hill at Lawrence Berkeley Lab, which had to read within millionths of a degree of absolute zero, or at the other extreme, temps hotter than the surface of the sun. Fortunately, my darkroom is nowhere near that uncomfortable!
 

and mercury did make a comeback for a while in fluorescent tube lighting, until LEDs finally won the day.
 

I have a couple of the same They both agree at all times and seem to be accurate based on the results I get when using them

pentaxuser
 
Mercury is funny stuff.

My neighbour works in a local chemical works where they produce mercury.
He is five foot ten inches tall, but on a hot day he is six foot two.
 
And how about all of the purple merthiolate / thimerosol our mom's used to put on us anytime we got an infection or scrape. I still have a few bottles left over that I refuse to use.
 
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