How important is temperature in developing B&W film?

[mackigator]

For someone like me - small batches done in 2 and 4 reel stainless tanks (sometimes months apart between developing sessions) - what is the fastest, easiest way to level off temps? I find preparing a bath at 20C to set the tanks in takes a little time and then it takes perhaps an added 30 minutes to get the temps in the containers to level off. This temp leveling ritual at least doubles my time to develop. Are there other ways?

[JohnTF]

To the OP, a little warm is going to affect the highlight density, but you are erring in to the area of latitude in the better direction, i.e. you are headed to where you should be able to easily correct during printing.

As you gain more experience, and wish to control your variables to a greater degree to make sure what you are doing in the camera and with your choice of film/developer combination match your intentions, --you will want to keep records and take better care of your procedures.

In summer in my darkroom, pure cold tap water, and chemistry sitting around, stay about 20 C, but it was not so hard or expensive to install mixing valves and a thermometer well in the cold side of my darkroom sink plumbing. The hot is simply hot, the cold side is plumbed from the mixing valve / thermometer well out lines, so I can see the temperature coming out of the "cold" side at a glance on the wall above the sink.

Your biggest problem would come from too cool, not a few degrees over, but it is a pleasure to print a properly exposed and developed negative as straight as possible.

I had obsessed friends who literally spent a year testing everything technical, sending the results to Ansel Adams, who wrote back it was the best technical quality he had seen, but they knew nothing about photography-- which they took as a compliment, as the image they sent was simply a set up for technique.

You can buy some gray scales and do a shot now and then on a roll to analyze how your film choice/processing/exposure is doing-- the better labs used to do this every day.

The goal is to control the variables so that you are getting what you were looking for when the shutter actuated.

Regards, John

[venchka]

Originally Posted by mackigator

For someone like me - small batches done is 2 and 4 reel stainless tanks (sometimes months apart between developing sessions) - what is the fastest, easiest way to level off temps? I find preparing a bath at 20C to set the tanks in takes a little time and then it takes perhaps an added 30 minutes to get the temps in the containers to level off. This temp leveling ritual at least doubles my time to develop. Are there other ways?

I use a plastic dish pan that fits in one side of my double sink. I place (4) 1 liter and (1) 2 liter bottles of water and a 2 liter bottle of fixer and my graduate with Xtol in the dish pan and fill the whole thing with water. The fixer & Xtol come from the fridge so they are at 34F. The tap water is 80F, plus or minus. Then I go load film, have a snack, watch TV, etc. until everything has settled to room temperature. Then I develop the film with enough tempered liquids to finish the process at very nearly the same temperature for all liquids. Certainly with 5 degrees or so.
I have used lunch box sized, frozen Blue Ice to speed the process, but I'm usually in no hurry.

Wayne

[Tom A]

My darkroom stays pretty constant 68F in the winter and - if the sun is blazing on the flat roof, about 5 degrees higher in the summer. I keep enough water in 2.5 ltr beakers to do pre-wash (when I do that) and also to mix developer and inter mediate wash. My water supply is set at 20C/68F (a 220 volt system with filtered water - a luxury that i do appreciate).
The critical part is that all the solutions are the same temperature throughout the cycle. Single shot developers (Rodinal. Xtol, d76) are a bit more sensitive to too high or too low temperature. Divided developers less so. I have found that you need several degrees difference (4-5F) to have to compensate with most films (TriX.XX etc). Slow films (Acros,PanF etc) is more sensitive to variations.
Older type films with the thicker emulsion can reticulate if you "shock" it (too cold water in the wash or intermediate wash).
If you dont have a precise control over the wash - keep one beaker with room temperature water handy -after the fix, use this and then stick the hose with the wash water in the tank and let it slowly dilute the room temperature water - less of a shock to the emulsion.
Film developing is more of a consistency process than following the "book". If you do it the same way every time - chances are that it will work all the time! One area where you dont want variables is in the darkroom!!!!!!

[Chris101]

Originally Posted by JohnTF

Come on, why not wait for partial differential calc?

It's a straight line, so m is constant, (the first derivative) -- never used calc in Chemistry-- it's more a physics thing for most ;-)

You did not think you were going to slip that one past did you? ;-)

...

That's why I said second semester. Eventually they tell you that the straight line models you learn in 101 are more convenient than true. Here is a very clear write-up of the temperature dependence of the rate of chemical reactions:

Chapter 2 of Upadhyay's Chemical Kinetics and Reaction Dynamics, Temperature Effect on Reaction Rate

Physics can get away with lazy math - just set all the constants to one and do the arithmetic on your fingers. In chemistry, you need to run real reactions and make measurements with lots of numbers in them. So using a tool like differential calculus, you can crunch an unquantifiable mess of changing concentrations into well isolated, and measurable, variables: concentration, time and temperature.

You don't need partial differentiation because when you do the experiments, you change only one variable at a time.

[Argenticien]

Originally Posted by Tom A

My darkroom stays pretty constant 68F in the winter and - if the sun is blazing on the flat roof, about 5 degrees higher in the summer. I keep enough water in 2.5 ltr beakers to do pre-wash (when I do that) and also to mix developer and inter mediate wash.

So it sounds as if you, like me, are not keeping the concentrate at 68 F, so like mine it will raise the temperature of the mixing water. I was thinking about this. Suppose in summer the developer is at 73 F. I often do Ilfosol in 1+14 (cheapskate proportion). I believe that if you assume water and developer have the same specific heat capacity (which they don't, but it must be close), you can in that case simply say that the temperature of the working solution will be 1/14 of the way between the mix water (68) and the developer (73), so 68.35 F. I've always ignoring this effect and used the dev time for the mix-water's temperature (here, 68) so actually I'm not far off. (Why didn't I do this calc before?!)

Doing the same calc for Rodinal in 1:50 or 1:100, you get to 68.1 or 68.05, so the difference is truly negligible.

Fix my maths if not right -- or if anyone knows the specific heat capacity of any developers, have at it.

--Dave

[venchka]

Don't you have a thermometer? Why guess or assume? Measure.

Wayne

[Dana B.]

Originally Posted by mackigator

For someone like me - small batches done in 2 and 4 reel stainless tanks (sometimes months apart between developing sessions) - what is the fastest, easiest way to level off temps? I find preparing a bath at 20C to set the tanks in takes a little time and then it takes perhaps an added 30 minutes to get the temps in the containers to level off. This temp leveling ritual at least doubles my time to develop. Are there other ways?

Simple: ice. Mix your developer. Take its temperature. Add a cube or two of ice, if needed. Stir. Repeat as necessary till it's 68*. Rinse thermometer. Develop.

I use a four-reel stainless tank (135, or two 120 reels). Only takes a couple minutes. Works for me.

[JohnTF]

Originally Posted by Chris101

That's why I said second semester. Eventually they tell you that the straight line models you learn in 101 are more convenient than true. Here is a very clear write-up of the temperature dependence of the rate of chemical reactions:

Chapter 2 of Upadhyay's Chemical Kinetics and Reaction Dynamics, Temperature Effect on Reaction Rate

Physics can get away with lazy math - just set all the constants to one and do the arithmetic on your fingers. In chemistry, you need to run real reactions and make measurements with lots of numbers in them. So using a tool like differential calculus, you can crunch an unquantifiable mess of changing concentrations into well isolated, and measurable, variables: concentration, time and temperature.

You don't need partial differentiation because when you do the experiments, you change only one variable at a time.

Am pretty sure Algebra 1 will suffice for most of it, or rely on Ilford and Kodak's charts and a well calibrated thermometer. ;-)

John

[JohnTF]

Originally Posted by Tom A

Older type films with the thicker emulsion can reticulate if you "shock" it (too cold water in the wash or intermediate wash).

Tom, the only time I experienced it, the film went from normal to very hot, to the point that any wiping would have removed the reticulated emulsion.

As I said, years later I tried to duplicate it, and gave up, but I have not researched what other have tried.

If I ever see the negative in the very old piles, I will scan and post it, though, I would certainly not hold my breath waiting.

Have you ever seen it in your work first hand?

John

[Argenticien]

Originally Posted by venchka

Don't you have a thermometer? Why guess or assume? Measure.

Wayne

I don't do cold-water baths for the bottles of chemistry. I'll admit this is partly laziness, but also lack of a proper container to do it in. I add ice as needed to the mixing water to get it down to 20 C, as my only temperature control mechanism. Once I've mixed the developer concentrate with the 20 C water, I of course can't add ice to the working solution, as it would then be too dilute. Therefore I don't measure the working solution's temperature, since there's nothing I can do about it. I figure the dilutive effect of adding more ice at that point would be material, where as the effects of leaving the working solution at 20.2 C or similar (while still using the 20 C developing time) has so far seemed to be immaterial.

--Dave

[jpa66]

I didn't vote, as I'm not sure exactly how I feel.

What's funny is that way back in the day when I first learned how to develop film, I NEVER took the temperature of the developer ( or any of the other chemicals ). I had worked at swimming pool for several years and took the temperature of the water there each day, so I figured that I knew from feel what 68 degrees F was ( LOL ). Thus, I just went by feel. All I shot in those days ( mid '80's ) was Tri-X. The funny thing is - nearly everything came out well.

Now I pay much closer attention to temperature, and try to be as precise as I can.

But every once in awhile, I get the itch to just let it fly again...

[muser53]

Here is my simple answer to a straight forward question. Temp matters. The better you can control all the variables involved from exposure to print the better you can consistently achieve what you intended to when you trip the shutter.

BTW Vinyl rules, even more so when combined with some tubes!

[DNG]

I try to get the developer at 20c, or from 18c to 23c, and adjust the time accordingly...

being off 2 degrees will change the time. (10% or so) And, to help trouble shoot, if needed, having a solid workflow is important.

[Chris101]

Originally Posted by JohnTF

Am pretty sure Algebra 1 will suffice for most of it, or rely on Ilford and Kodak's charts and a well calibrated thermometer. ;-)

John

I've never actually used algebra to develop film. The results would probably be ... (wait for it) ... variable.

[crawdiddy]

I try to achieve 20 C, but I'll always try to err on the warm side, given a choice. I don't like thin negatives. Of course, with Tri-X, HP-5, Arista, Neopan and D-76, there's a fair amount of lattitude.

[JohnTF]

Originally Posted by Chris101

I've never actually used algebra to develop film. The results would probably be ... (wait for it) ... variable.

Algebra is (wait for it) what the Little Mermaid had to wear for the Disney movies.

[V-12]

How would the people who said 'a few degrees either way' teach somebody to drive?

"Son, keep both hands on the wheel at all times"

"Aw gee dad, all the time?"

"OK son, well only if you aren't picking your nose, hanging your arm over the back of your girlfriends seat, hanging your other arm out the window on a hot summer night, tuning the radio, drinking beer, or showing your friends how to drive with your knees and no hands on the wheel."

"Thanks dad"

I think 'a few degree's either way' should be kept to yourself, so you can deal with it, and not pass that advice on to beginners to deal with because 'they read it here first'.

Shame on you.

[venchka]

When mixing concentrated developer and water, it is very possible to use a frozen solid to lower the temperature of the working solution without over diluting the working solution. I leave it to your imaginations to solve the problem. There is a second method that doesn't involve frozen solids. It is slower, and more precise.
Suffice to say the temp. of developer and time in the developer are but two of several variables that define the final print.
I choose to use the temp. that I can easily maitain and duplicate combined with an amount of time that yields sastisfactory results within the confines of the other variables.
Clear as mud,hey!

Wayne
Ps: Agreed. Vinyl+Tubes = ROCKS

[dbm]

Originally Posted by venchka

When mixing concentrated developer and water, it is very possible to use a frozen solid to lower the temperature of the working solution without over diluting the working solution. I leave it to your imaginations to solve the problem. There is a second method that doesn't involve frozen solids. It is slower, and more precise.
Suffice to say the temp. of developer and time in the developer are but two of several variables that define the final print.
I choose to use the temp. that I can easily maitain and duplicate combined with an amount of time that yields sastisfactory results within the confines of the other variables.
Clear as mud,hey!

Wayne
Ps: Agreed. Vinyl+Tubes = ROCKS

Or make ice cubes from properly mixed solutions? Since the "ice" has the same concentration as the solution, it wouldn't affect the concentration of the warm solution when added.

Obviously, never use that tray for regular ice again!

[BardParker]

+1 on the Massive Development Chart App for iPhone/android/Nokia. It has a temperature convertor built in to the timer and automatically adjusts time. Makes everything super easy and consistent. That way I don't have to mess with ice, etc. Works great for me!

If you don't have mobile device that is compatible just use this online link:

http://www.digitaltruth.com/devchart.php

Kent

[DNG]

I do use ice (small prices) to cool down the Developer during the Summer. But, I like the idea of making a working dilution tray of developer ice cubes!.. Brilliant!

[znapper]

I always keep the developer within +-0.2 degrees of 20 C.
Wash and fix, I keep within +-2 degrees to avoid reticulation issues.

Consistency - consistency - consistency- consistency!!!

[pdh]

Originally Posted by znapper

I always keep the developer within +-0.2 degrees of 20 C.!

Wow that's a very tight tolerance, I'm interested to know how you go about achieving that.

So, let's say for example you were developing 35mm film in a Paterson tank, and it needed 7 minutes at 20C with an inversion every 30s

What kind of thermometer are you using that is accurate and easy to read to such a scale?

How would you both monitor the developer temperature to such a tolerance, and maintain it (increasing or decreasing it as required) at the same time as not disturbing the tank in such a way as to mess up the agitation regime?

[znapper]

Originally Posted by pdh

Wow that's a very tight tolerance, I'm interested to know how you go about achieving that.

So, let's say for example you were developing 35mm film in a Paterson tank, and it needed 7 minutes at 20C with an inversion every 30s

What kind of thermometer are you using that is accurate and easy to read to such a scale?

How would you both monitor the developer temperature to such a tolerance, and maintain it (increasing or decreasing it as required) at the same time as not disturbing the tank in such a way as to mess up the agitation regime?

I use a (very cheap) digital thermometer and measure up around 1 gallon of water in a holding tank, fitted with a purifying filter.
I keep nudging the water tap until I have 20 degrees (+-0.2 degrees) before I put that into a 1 liter jug, I have the thermometer in the jug while I fill it, in case temperature flux occur (people may start the shower or the dishwasher may start etc).

I know that the temperature probably varies a little bit during development, but it's not much during a 5-9 minute development.

My room temperature is usually very close to 20 degrees as well, so I don't get that extreme influence you may get in a hot climate.

The thing here is consistency, not necessarily 20 degrees exact.
You can develop at 30 degrees if you like, as long as you measure stuff and keep things as equal as possible every time.

If you measure temperature "by finger" and vary your agitation scheme wildly, you will never know what you did right/wrong and you will never be able to get reproducible results.