Paterson Thermometer

[Mamulcahy]

I pulled out my thermometer to develop some film last night and found out the blue liquid had separated with about a half inch at the top of the thermometer. I had the idea of heating the thermometer up in water on the stove to reunite the liquid and that worked, but I’m concerned about the reliability of the readings now. Anyone else have this problem? Any advice is appreciated!

 

[koraks]

This is common with alcohol thermometers. Actually, it used to happen with mercury thermometers, too, but these were even easier to 'fix' by just forcefully whipping the thermometer a couple of times so that centrifugal forces push the liquid back towards the end. This works with alcohol thermometers as well, but a little less so than with the old mercury ones.

Sometimes, the liquid won't reunite whatever you try and at that point your thermometer is toast. It tends to happen if you overheat it so that the liquid expands all the way up the column, or when the thermometer is being subjected to shocks (e.g. by dropping it).

I don't think any impact of this on its accuracy is worth losing any sleep over. Especially for B&W it won't matter much at all, if the accuracy is affected in the first place, which I doubt.

 

[Nitroplait]

Your Paterson thermometer probably wasn't reliable when it came to measuring the correct temperature in the first place, but it is irrelevant, because it serves its purpose by supporting consistency and repeatability.

After the event you describe, the actual reading may have changed a little from before - maybe it now shows 20.5ºC where if would have shown 20.0ºC before. This is just a new reference point. It may be within allowable variations or may need a small adjustment in your process.

If you buy a new thermometer, you will have to go through the same calibration anyway, even if you buy the same product again as no two consumer thermometer can be expected to show the exact same result.

 

[Ian C]

https://www.globalgilson.com/blog/rejoining-separated-columns-in-thermometers-6-dos-and-donts

https://www.carolina.com/teacher-re...ning-separated-thermometer-columns/tr40203.tr

https://icllabs.com/how-do-i-rejoin-mercury-separations-instructions-in-english-spanish/

 

[Doremus Scudder]

I've done this with a number of thermometers. The readings won't change unless there is still a bit of the fluid that hasn't been re-incorporated with the main reservoir. Many thermometers have a bulb at the top of the scale just to facilitate reintegrating the column should it become separated. With those that don't, you have to be very careful when heating the thermometer when the column approaches the top that you don't overheat and break the glass due to expansion.

Best,

Doremus

 

[Randy Stewart]

When you buy Paterson, you buy cheap. Bin the thing. Buy a new digital unit. The $20 kitchen thermometers are more than adequate for home photo processing. They are usually accurate to a quarter degree F (scaled to 1/10 degree). They register in a few seconds, as opposed to a minute or more for an alcohol unit. For decades, I've used more expensive (higher quality) dial units, which I calibrate to a Kodak Process (mercury) unit. then one day, I said to myself, why bother?

 

[Brad Deputy]

This happened, in rather short order, with my Paterson B&W Thermometer.

I've since bought their color thermometer, with no issues for over 2 years now.

I think I overheated it by leaving it in the sink when I was washing the reels and tank at 120+ degrees.

I've found their thermometers to be accurate to <0.2 degree F, as long as they're not abused. I hear using them to stir your developer is a bad idea...

 

[Bill Burk]

Paterson thermometer is a decent one. Maybe not as good as Kodak type 3. But I have one. It’s my main reference thermometer.

As long as you joined the liquid you should be fine. If you can’t see blue in the top or breaks in blue in the column you probably fixed it.

This happens to these all the time.

 

[Augustus Caesar]

I suggest the Kodak Process Thermometer Type 3. Mercury type.

 

[Bill Burk]

Every long glass thermometer I’ve owned has broken except the Paterson.

Nothing special or magical keeps it from breaking… just hasn’t happened yet.

So I probably won’t get another mercury one. That was a heck of a mess to clean up.

 

[Doremus Scudder]

My Paterson Color Thermometers match my Kodak Process Thermometer very closely (as well as each other). My dial thermometers get calibrated using the Kodak thermometer occasionally. All close enough for B&W.

I imagine the OP's Paterson thermometer is also adequate as long as the separation issue has been rectified.

Best,

Doremus

 

[miha]

I droped my Paterson Colour Thermometer a while ago, it broke, no surprise. At the moment I'm using a Kaiser made one, I think it's called Kaiser Precision Thermometer. It's thicker and looks more durable. For BW i'm using a shorter, simpler Kaiser Tray (angled) thermometer.

 

[Bill Burk]

Oh the Kodak tank and tray thermometer I bought in high school still works fine. Knock on wood it never broke

 

[Tim Stapp]

I buy mine at the local wine making/brewery supply shop. I did suggest to them that they not store them horizontal in the sun shining through the front window, because I had to sort through to the bottom of the box to fine a couple that hadn't separated in either shipping or storage.

I only use them to measure BW chemical temps in the JOBO. They match my JOBO bath thermometer and each other. So I just go with them.

I've only handled a Kodak Process thermometer once. I needed to calibrate a dial type for an industrial process 40 plus years ago. My supervisor borrowed his wife's for the purpose. She was part of the process because she refused to let it out of her sight. She basically let me touch it )

 

[Doremus Scudder]

My Kodak Process Thermometer is kept in a special drawer wrapped in bubble wrap in a cardboard tube until I need it to calibrate my other thermometers. It only gets used for reference.

Doremus

 

[Mick Fagan]

I started using electronic thermometers around 40 years ago when using industrial film processing equipment. They were so much easier and quicker and supposedly more accurate; but the cost was prohibitive.

In 1991 I bought a new manufacturing process for my business, which required very accurate temperature monitoring. To that end I picked up a $1,000 USD (or thereabouts) electronic thermometer with supposedly fantastic accuracy. It was certainly good enough for the job and by changing to a different probe, I also started using it for my photography. I was hooked on electronic thermometers.

Today I have a very cheap, reliable splash proof electronic thermometer for my photography. It is simple and is now what I use exclusively for photography, cost was around $20 AUD when I purchased it around 5-6 years ago.

This is very similar, if not identical to what I have.

Waterproof Thermometer - Ravi Scientific Industries

Measuring Range -50~300 C/-58~572 Resolution 0.1°C Accuracy ±1 Function °C & °F unit selectable With Probe cover Power Source 1 x 1.5v (LR44) Packing

www.raviscientific.in

 

[MattKing]

My Kodak Process Thermometer is kept in a special drawer wrapped in bubble wrap in a cardboard tube until I need it to calibrate my other thermometers. It only gets used for reference.

Doremus

Similar for me. Except not a drawer because, as mentioned on the box and I think the instructions, it should be stored standing upright on its end.
Having it allows me to use much less expensive digital thermometers for daily use.

 

[Dustin McAmera]

I once had a mercury thermometer, but, having seen people cleaning up spilt mercury at the university where I then worked, I took that thermometer to work and abandoned it in the lab. I still have a couple of spirit thermometers, but I use an Adox dial thermometer for most things. Not as good a stirrer as a glass thermometer though...

 

[Doremus Scudder]

Similar for me. Except not a drawer because, as mentioned on the box and I think the instructions, it should be stored standing upright on its end.
Having it allows me to use much less expensive digital thermometers for daily use.

Hmmm... my instructions for the Kodak Process Thermometer, Type 3 state, "A hole is provided in the back plate so that it can be hung vertically when not in use." I don't necessarily read this as a recommendation to always store the thermometer vertically. Still, I might rethink my storage situation.

Best,

Doremus

 

[MattKing]

Hmmm... my instructions for the Kodak Process Thermometer, Type 3 state, "A hole is provided in the back plate so that it can be hung vertically when not in use." I don't necessarily read this as a recommendation to always store the thermometer vertically. Still, I might rethink my storage situation.

Best,

Doremus

Here are the instructions themselves:
https://www.photrio.com/forum/threads/kodak-process-thermometer-type-3.137713/#post-1801991
The Kodak box for mine has stamped on one end a rubber stamp that reads: THIS SIDE UP.
The stamp looks official.

 

[Augustus Caesar]

I once had a mercury thermometer, but, having seen people cleaning up spilt mercury at the university where I then worked, I took that thermometer to work and abandoned it in the lab. I still have a couple of spirit thermometers, but I use an Adox dial thermometer for most things. Not as good a stirrer as a glass thermometer though...

So far as I know, elemental mercury is not much pf a hazard. It's the compounds that are toxic.

 

[John Wiegerink]

I posted in the thread Matt linked to and have never had my Kodak Lab thermometer separate stored horizontal in its original box. When I had my original fully equipped darkroom in my home down south, it hung on the wall above the sink, but now my darkroom is my wife's laundry room at our northern cottage home. I have to clean all my "stuff" out of there before she does a batch of dirty clothes, so now the Kodak thermometer lays flat in its box. I'm very glad to have the Kodak thermometer and won't part with it. In the link Matt posted, I explain the hassle I had with a well named digital thermometer sold by a large photographic company. All I can say is, never again.

 

[Doremus Scudder]

Here are the instructions themselves:
https://www.photrio.com/forum/threads/kodak-process-thermometer-type-3.137713/#post-1801991
The Kodak box for mine has stamped on one end a rubber stamp that reads: THIS SIDE UP.
The stamp looks official.

Same instructions I have. No admonition to always store the thermometer vertically, just a mention that there is a hole for hanging it vertically. I never had a box. I'll do a bit more research.

Doremus

 

[_T_]

So far as I know, elemental mercury is not much pf a hazard. It's the compounds that are toxic.

Elemental mercury is incredibly toxic just not as a liquid. Unfortunately it evaporates readily where it can be inhaled and absorbed directly into the bloodstream.

A mercury spill is a major problem and can be very difficult to clean.

 

[Maris]

A dropped and shattered mercury thermometer is a problem in a restricted space like a photographic darkroom. Mercury can spill into thousands of tiny globules that fall into the tiniest gaps and cracks from where mercury vapour can emerge for months or years. A chemical solution to the hazard is also in the darkroom: sulfide based sepia toner. Swabbing mercury contaminated surfaces with dilute sepia toner converts the hidden mercury to mercury sulfide which is stable and non volatile; a nasty solution to a nasty problem.
I bring only spirit thermometers like the Paterson into my darkroom.