Another Thermostat Thread...

So, which one do I trust?

I know this OLD JOBO CPE (original, not 2) fluctuates "violently" or so says the previous owner (thank you for your backup!) the great Ralph! Great price and works well now that I got a good transformer! And thank you to the great John for recommending this transformer unit...



Anyway enough of the praise and thanks...

It seems all my thermostats are in disagreement...

This is LESS of a problem in B&W but part of the reason for this unit is to start doing color again, which I haven't done since early 2013 because it's a pain without a processor, it's doable, but easier when you don't have to panic that your water bath is off...

So... Seems we have a problem...









The one that I've had since the beginning brand new from B&H was the RED "Cooper" labeled one, the larger one that's film specific I got from an old gentleman who was very kind from NJ and gave me a lot of stuff he could no longer use due to health problems, I thank him as well, the other two are kitchen thermometers of my parents just for comparison, I did thoroughly clean the JOBO water bath area and the water is fresh, and I will rigorously scrub the two kitchen thermostat/thermometer whatever the proper name is, after I'm done so no one in the house gets sick just in case. Anwyay... Currently (pictures may be off by a few as it's been 10 minutes since I took them) the film specific one says it's 77 degrees, my red copper says 69, the "true temp NSF" says 71 and the black cooper at the end says 63.... Wha??????

Which do I trust and how would I ever know which is true? And if I've been going by the red cooper the whole time except recently when I switched to the film specific one, I was rotary processing so lowering the temp for my times was probably a lucky move as the negs have been a little dense since I switched to rotary, but if I had gone with the red cooper temps they would have been cooked!

So what do I do? And please don't tell me to buy some fancy expensive electronic device to measure the temp, but, but in all practicality, which one should I trust?

Thanks.

Boil some water and see which of the two that go all the way to 220 are closer to 212.

sometimes round dial thermometers need to be calibrated
theres probably a thread here or somewhere online how to do it ..

infra red / laser thermometers are cheap and very accurate
http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias=aps&field-keywords=laser+thermometer

It could be they are all wrong.
A properly calibrated thermometer (which is not the same thing as thermostat) is the way to know what temperature the water in the bath is.

BTW - how will you temper the developer? Either way use the same thermometer to check the water bath as the developer.
Unless you have two that read the same.

Ah, thermometers ......

Almost all rotary dial thermometers feature the ability to re-calibrate them - usually by adjusting a nut or something similar at the back.

This means that they are usually wrong, unless and until they have been correctly adjusted.

What I do with thermometers is:

1) obtain a thermometer that I can trust to be accurate - my "reference" thermometer (see more below);
2) on a regular basis, compare the readings of my cheaper thermometers against the reference thermometer, and adjust them where I can to match.

What sort of thermometer do I used as a reference? A thermometer that is generally of good quality, relatively more fragile than my cheaper thermometers, and capable of being checked as to calibration.

In my case, I use a Kodak Process Thermometer model 3 as a reference. It is a mercury thermometer which can be found used for a fair amount of money (I got a good deal on mine). It is extremely well made, about 14 inches long, surrounded by stainless steel and can be checked for calibration using an ice water bath.

Here is a picture of one with the matching instructions: http://www.flickr.com/photos/etr420/9280657696/

If you are not fortunate enough to obtain the Kodak Process thermometer as a reference, a decent lab grade thermometer could be used. I believe the Paterson colour thermometers are also quite good.

Here is another thread on the same question: (there was a url link here which no longer exists)

EDIT: The infra-red thermometers that jnanian linked to may very well do the job for you - you just need to check them first with both an ice-water bath, boiling water and a couple of sacrificial rolls developed at what appears to be your normal developing temperature.

MattKing said:

Ah, thermometers ......

Almost all rotary dial thermometers feature the ability to re-calibrate them - usually by adjusting a nut or something similar at the back.

This means that they are usually wrong, unless and until they have been correctly adjusted.

What I do with thermometers is:

1) obtain a thermometer that I can trust to be accurate - my "reference" thermometer (see more below);
2) on a regular basis, compare the readings of my cheaper thermometers against the reference thermometer, and adjust them where I can to match.

What sort of thermometer do I used as a reference? A thermometer that is generally of good quality, relatively more fragile than my cheaper thermometers, and capable of being checked as to calibration.

In my case, I use a Kodak Process Thermometer model 3 as a reference. It is a mercury thermometer which can be found used for a fair amount of money (I got a good deal on mine). It is extremely well made, about 14 inches long, surrounded by stainless steel and can be checked for calibration using an ice water bath.

Here is a picture of one with the matching instructions: http://www.flickr.com/photos/etr420/9280657696/

If you are not fortunate enough to obtain the Kodak Process thermometer as a reference, a decent lab grade thermometer could be used. I believe the Paterson colour thermometers are also quite good.

Here is another thread on the same question: (there was a url link here which no longer exists)

EDIT: The infra-red thermometers that jnanian linked to may very well do the job for you - you just need to check them first with both an ice-water bath, boiling water and a couple of sacrificial rolls developed at what appears to be your normal developing temperature.

Click to expand...

I was surprised at the cheap price of the IR thermometer gun, but your mention of mercury thermometer sparked a memory...

Would THIS do??

it's a kodak thermometer, it's blue so not mercury, but will this be more trustworthy?



Also found another film thermometer...

I've used a pyrex brand digital kitchen thermometer for the last ten years. Got it at a kitchen store. It matches my old kodak and I've never had an issue processing chromes.

Stone:

The blue Kodak thermometer may very well be a good reference. If it goes down to 32F/0C see how it reads the temperature of a water and ice bath.

If it seems good, compare it to your others to see if one measures similarly at 68F and 100F. If there is one, use that as your regular thermometer, and check it regularly against your carefully stored reference.

Or get a kitchen thermometer like wildbill and compare it to your reference. That's what I do. The waterproof ones are best.

MattKing said:

Stone:

The blue Kodak thermometer may very well be a good reference. If it goes down to 32F/0C see how it reads the temperature of a water and ice bath.

If it seems good, compare it to your others to see if one measures similarly at 68F and 100F. If there is one, use that as your regular thermometer, and check it regularly against your carefully stored reference.

Or get a kitchen thermometer like wildbill and compare it to your reference. That's what I do. The waterproof ones are best.

Click to expand...

Hmm 35-180 is the glass one, it has a carrot " ^ " at 64 degrees was that an older processing temp? This thing is old, comes with a cardboard tube, cost $2.00 and I can't say for sure but came with a bunch of other equipment from the 1950's

I've adjusted all the thermometers to match the glass one, it was easy to turn the back nut( or if no nut was provided, the back protrudent piece from the interior that is where the nuts on the newer thermometers had them, was also adjustable with some elbow grease...

Let's hope the glass one is correct...

Nice to see that Jobo being put to use. The thermostat on the cpe may be able to be adjusted by rotating the knob on the shaft. I'd agree that the preferred method of working with dial thermometers is to set them to match your good mercury thermometer and keep the mercury thermometer out of harm's way.

Go to the drug store. Look for the therometers that you use to take your temperature. They are cheap and usually very accurate at the temperature they are made to work at.
That would be about 37C or 98F or a few degrees higher if you have a fever. That is very close to the temperature of color development.

As the setup is intended for colour processing, a clinical thermometer would be the easiest and most cheap way to have a good reference thermometer at hand.

Oops, Brian gave already the same advise.

ic-racer said:

Nice to see that Jobo being put to use. The thermostat on the cpe may be able to be adjusted by rotating the knob on the shaft. I'd agree that the preferred method of working with dial thermometers is to set them to match your good mercury thermometer and keep the mercury thermometer out of harm's way.

Click to expand...

Yea, though the motor is sketchy at best, and when using it the first time I was told it could easily take the weight of a small 1500 tank, it couldn't and it bent the shaft of the motor so now sometimes it won't reverse directions... I fixed it, thankfully, but I'll certainly be selling it to a newbie for the price I got it for when I get a newer CPP2 with the lift... Never saw the value in all of this till I used one!

And yes the knob adjusts the temperature but it's highly inaccurate, hence the sharpie black dot I added to the "scale" markings, I think there might have been one previously but I basically added my own darker mark on top so I could see it

I broke my excellent mercury thermometer, so if I get another it will only be used to carefully calibrate the rest. In the mean time I use an inexpensive digital thermometer (http://www.amazon.com/Taylor-9842-C...394317459&sr=8-3&keywords=kitchen+thermometer) that can be calibrated to check my dial thermometers. Surprisingly the Taylor came from the factory reading dead on in ice water and boiling was only off by a fraction of a degree (probably because my house is a few feet above sea level). So I assume it's fairly close in between as well.

StoneNYC said:

I was told it could easily take the weight of a small 1500 tank, it couldn't and it bent the shaft

Click to expand...

That is too bad about the shaft, was the tank sitting on the rollers? Is there anything smaller than a small 1500 tank? Does this machine take a special tank?

ic-racer said:

That is too bad about the shaft, was the tank sitting on the rollers? Is there anything smaller than a small 1500 tank? Does this machine take a special tank?

Click to expand...

I believe it was modified to take the 2500 tanks and that the 1500 tanks COULD have been used with support if I had rollers on higher "arms" however there are only inserts for the lower arms and the higher arms are non-existent.

So the 1500 tank is only supported by the water and the shaft itself, and the water doesn't do much since the motor shaft is too high over the water.

I'm just going to use the 2500 tanks from now on, but I only have one lid that has the "inversion" rubber piece, I am trying to trade some JOBO gear now, including some lids with the gears for a lid with the inversion stopper but no one has contacted me about a trade or purchase yet.

StoneNYC said:

So the 1500 tank is only supported by the water and the shaft itself,

Click to expand...

I was looking closely at the pictures to see if these roller extenders for the 1500 tanks would fit;

ic-racer said:

I was looking closely at the pictures to see if these roller extenders for the 1500 tanks would fit; View attachment 83949

Click to expand...

They Might... But I would need glue and they wouldn't be removable...




It looks like there used to be other feet glued in...

I COULD put those on a wooden board or something and then just insert that when I need to use the smaller tanks, but it's not worth the bother, I almost always have more than one roll of film to develop anyway...

Jobo made a set of rollers for table top use. It's basically two bars with the clips installed. It would sit nicely in the bottom of that processor and allow you to use the different rollers at the correct height. Mine is not for sale since I use it to support the Expert print drums in my processor that are two long for the lift to be adequately supported. But maybe you can find one if you keep looking.

L Gebhardt said:

Jobo made a set of rollers for table top use. It's basically two bars with the clips installed. It would sit nicely in the bottom of that processor and allow you to use the different rollers at the correct height. Mine is not for sale since I use it to support the Expert print drums in my processor that are two long for the lift to be adequately supported. But maybe you can find one if you keep looking.

Click to expand...

Thanks, I'm not sure how much it costs but it's probably not worth it, I have to get a better processor with lift anyway. But I'll look into the price of one, thanks.

StoneNYC said:

Thanks, I'm not sure how much it costs but it's probably not worth it, I have to get a better processor with lift anyway. But I'll look into the price of one, thanks.

Click to expand...

Google has already done this research...:

https://www.google.com/search?q=job...0...1ac.1.34.heirloom-serp..8.0.0.ExySnqkL55g

My dial thermometer has a small nut on the back, you can adjust it using a small, flat wrench. Once you get a good reference temperature you should be able to calibrate the others.

adelorenzo said:

My dial thermometer has a small nut on the back, you can adjust it using a small, flat wrench. Once you get a good reference temperature you should be able to calibrate the others.

Click to expand...

Thanks Anthony... You should read the whole thread

But thanks, you're correct.

I did read the whole thread.