Can I put a thermometer directly into the developer to check temp?

I'm developing ECN-2 at home for the first time (I haven't developed any film before), and the developer needs to consistently be at 41 degrees. I have the cinestill TCS-1000 to keep the water in the bucket at a stable temperature but i'm skeptical whether the bottles i'm using to hold each solution will differ in temperature on the inside.

 

For this reason, is it okay to put a metal thermometer directly into each solution to check the temperature?

Edited December 30, 2020 by sethbaldwin

Should be ok, rinse it in between. To reduce the risk, go through the chemicals in processing order, don't go backwards.

 

Provided everything has been sitting in the water bath long enough, it will be at the same temperature.

 

First time? Start with something simple, traditional monochrome film in well known developer like D-76.

I probably recommend trying at least one roll of black and white first, just to get used to the feel of pouring and timing.

 

The usual rule is to time from beginning of pour to beginning of the next pour, which takes a little practice.

I suppose one could practice pouring water, but film is more fun.

 

And, yes, stainless steel thermometers (and tanks) are designed to work with color film processes.

Specifically, the bleach used is meant to oxidize silver, and eventually dissolve it, and could do many other metals.

 

Otherwise, be sure not to contaminate developers, so wash between other chemicals and developers. The other way around is usually fine.

But then again, the developers are the ones that need to be close to said temperature.

You can be pretty far off for the others, though best not to have a big difference step to step.

For this reason, is it okay to put a metal thermometer directly into each solution to check the temperature?

How else are you going to get an accurate reading of temperature?

 

Any decent thermometer with a metal probe will use stainless-steel as the sheath material. So, yes, perfectly OK to immerse stainless steel in any commonly used photo-chemical.

 

As Glen said, the only corrosive chemical is colour bleach or bleach-fix (Blix). This can - eventually - etch the surface of stainless steel, and indeed a stainless steel tank/spiral used extensively for colour processing will lose its polish and become dull with use. However the time that a tank and spiral are in contact with bleach is far longer than the quick dip'n'read that it takes for a temperature reading.

 

Oh, BTW: The fact that a digital thermometer shows the reading down to 0.1 degree gives a false impression of accuracy. Most cheap and uncalibrated digital thermometers can be anything up to 2 degrees out. Especially little kitchen meat-probe types. They really ought to be ice-water and boiling-point calibrated, or checked against a known accurate standard.

Edited December 30, 2020 by rodeo_joe|1

I used to have actual Nikor tank instructions, which recommended a dip in strong nitric acide to repassivate.

I have never done that.

 

Do note, though, that not all stainless steel is the same.

 

I did have a stainless steel bowl that I didn't use for full strength color chemicals,

only rinse water, and it still got a hole in it.

Wow, never heard about repassivating tanks. Sure, it works, but nitric is so dangerous that nobody should do it. Clean 'em up with Bar Keeper's Friend if you have to.

Lol I just did it without a thermometer and the negatives seem to look good. Had the developer in the bucket with the water heated at 41 degrees for about an hour. I also practice rehearsed the process about 10 times before doing it for real. Will see how the scans look tomorrow, maybe send them through. Edited December 30, 2020 by sethbaldwin

As I have said before, my B&W processing is full-strength D-76 at whatever temperature it's at, for 8 minutes, more or less.

 

Works fine and inevitably produces negatives that are good enough for scanning.

 

Obviously, such slap-dash control is unlikely to produce "optimum" results, most especially with color film.

 

The best is the enemy of the good

Voltaire, I think

Edited December 30, 2020 by JDMvW

Wow, never heard about repassivating tanks. Sure, it works, but nitric is so dangerous that nobody should do it. Clean 'em up with Bar Keeper's Friend if you have to.

 

Says 25%, so still dangerous, but not that dangerous!

 

honeywell_nikor_tank(1).pdf

Thanks for posting the Nikor sheet. I always wanted one of those rotary trimmers, but too rich for me. I've got a Carl instead, which is OK for hobby use.

By the way, if you are close it only needs to average 41C.

You can start at 43C and end at 39C, and it will be fine.

If you know the cooling rate, it can be done that way.

I always put a glass thermeter into my Minox development tank ,then move it up and down to agitate the developer, this a standard procedure in Minox film development---

Called thermometer pumping

Word of warning - don't mop up spilled Nitric Acid with anything cotton - can make Nitro-Cellulose, aka Gun Cotton ! Chemistry Teacher got somewhat upset when that happened.