How nuts are you about temperature?

[DREW WILEY]

Sirius - Jobos are anywhere near within 1/10th C. You'd have to put a probe inside the drum solution itself under rotation to determine the real variables, and that itself would change with solution volume and ambient air temperature. The exterior water bath temperature is just one variable of several, and I outright know it's not that tight a tolerance itself, having measured that, and know the limitation of its own kind of relatively simple technology. Maintaining tight temp INSIDE a drum requires a much better insulator wall than just thin ABS plastic. But Jobo gear is in fact well within reason for most film and paper development purpose, provided your solutions themselves have reached equilibrium in their bottles.

 

[Sirius Glass]

Sirius - Jobos are anywhere near within 1/10th C. You'd have to put a probe inside the drum solution itself under rotation to determine the real variables, and that itself would change with solution volume and ambient air temperature. The exterior water bath temperature is just one variable of several, and I outright know it's not that tight a tolerance itself, having measured that, and know the limitation of its own kind of relatively simple technology. Maintaining tight temp INSIDE a drum requires a much better insulator wall than just thin ABS plastic. But Jobo gear is in fact well within reason for most film and paper development purpose, provided your solutions themselves have reached equilibrium in their bottles.

But Jobo gear is in fact well within reason for most film and paper development purpose, provided your solutions themselves have reached equilibrium in their bottles. ==> exactly my point. If one is using the equipment correctly, take the temperature measurement from the equipment or putting a thermometer in the bottles, use tables and/or interpolation to get the time, and do not bother if and only if the temperature measurement is within the appropriate tolerance. Then the rest is just chatter.

 

[faberryman]

We have talked a lot about temperature, but have overlooked time. When Kodak says to develop for 9 minutes, isn't it curious that it is not 8:59 or 9:01? Ilford's time and temperature conversion chart is in 15 second increments. Good enough? Do you use a metronome, a wrist watch, the timer on your phone, or the atomic clock in Boulder? Does the last drop of developer always fall out of the tank at exactly the same time every time? Are you consistent to the second every time you pour in the stop bath? Do you even use stop bath? There are a lot of areas when there is opportunity for slight variations. Add them all up and is a focus on 1/10th of a degree misplaced? Is it false precision? Again, I am not suggesting being sloppy, but maybe the fact that your thermometer is not accurate to 1/10th of a degree is not why your phone is not ringing off the hook with New York galleries wanting to show your work, and buying a $300 process thermometer is not the thing that is going to take your photography to the next level.

 

[Chan Tran]

We have talked a lot about temperature, but have overlooked time. When Kodak says to develop for 9 minutes, isn't it curious that it is not 8:59 or 9:01? Ilford's time and temperature conversion chart is in 15 second increments. Good enough? Do you use a metronome, a wrist watch, the timer on your phone, or the atomic clock in Boulder? Does the last drop of developer always fall out of the tank at exactly the same time every time? Are you consistent to the second every time you pour in the stop bath? Do you even use stop bath? There are a lot of areas when there is opportunity for slight variations. Add them all up and is a focus on 1/10th of a degree misplaced? Is it false precision? Again, I am not suggesting being sloppy, but maybe the fact that your thermometer is not accurate to 1/10th of a degree is not why your phone is not ringing off the hook with New York galleries wanting to show your work, and buying a $300 Kodak process thermometer is not the thing that is going to take your photography to the next level.

1/10th of a degree would have more effect than 15 sec. for a 9 minutes process.

 

[Alex Benjamin]

There are a lot of areas when there is opportunity for slight variations. Add them all up and is a focus on 1/10th of a degree misplaced? Is it false precision?

This sums up my present questioning very well. As many here have mentioned, consistency is a key, but another important one is developing the ability to analyse your negatives and adjust. But then, consistency and adjustment aren't that easy to put in place since there are so many opportunities for variations.

Oh, and since I live in a split-level home, when I want to move my photography to the next level I just take the stairs.

 

[Saganich]

Nuts enough to buy a compensating timer, that measures temperature and compensates development time. I never liked figuring that out. Occasionally I check it against 20C to see how well it's doing. I have several lab-grade thermometers and one master thermometer. I use all of them to measure temp and then take the average and adjust my faucet thermometer. I've never had two thermometers that read the same. It's about being consistent and checking assumptions rather than being correct.

 

[Doremus Scudder]

I tray develop by hand with the developing tray inside a larger tray with a tempering bath. Ambient temperature is usually within a degree or so of 20°C. I start with 20°C developer and tempering bath and use the compensating developing timer. The probe goes into the tempering bath.

At the end of a 15-minute development, I normally measure the developer temperature with a thermometer that has been checked against my Kodak process thermometer. Rarely is the developer temperature more than 1°C different (usually warmer, which I attribute to my (gloved) hands being in the developer). That's close enough for me.

Doremus

 

[Sirius Glass]

We have talked a lot about temperature, but have overlooked time. When Kodak says to develop for 9 minutes, isn't it curious that it is not 8:59 or 9:01? Ilford's time and temperature conversion chart is in 15 second increments. Good enough? Do you use a metronome, a wrist watch, the timer on your phone, or the atomic clock in Boulder? Does the last drop of developer always fall out of the tank at exactly the same time every time? Are you consistent to the second every time you pour in the stop bath? Do you even use stop bath? There are a lot of areas when there is opportunity for slight variations. Add them all up and is a focus on 1/10th of a degree misplaced? Is it false precision? Again, I am not suggesting being sloppy, but maybe the fact that your thermometer is not accurate to 1/10th of a degree is not why your phone is not ringing off the hook with New York galleries wanting to show your work, and buying a $300 process thermometer is not the thing that is going to take your photography to the next level.

Just be consistent in timing: start and end timing with beginning of the pour, or the middle or the end.. Just be consistent. I use a the buzzer of the Gralab timer. Stop bath is supposed to be 30 seconds, I use a little more than a minute. For fixer I use between 5 and 10 minutes depending on previous usage.

 

[grat]

1/10th of a degree would have more effect than 15 sec. for a 9 minutes process.

And yet, the Ilford chart being discussed assumes a 1°C delta is equal to 2°F-- a 10% error right there (should be 1.8).

Further, looking at the chart, for 9 minutes, +/- 2°F @ 68°F is a minute's difference in time-- divide 60 seconds by 20, since there are 20 tenths in 2 degrees, and 1/10th of a °F should affect your time by 3 seconds (6 seconds for °C).

Extrapolating that to 15 seconds, the smallest interval most developing charts give, and it seems that any error below 0.5°F shouldn't really matter-- for 9 minutes of developing time, at least.

I think most people would be hard pressed to tell the difference.

 

[Vaughn]

The proof is in the printing...
I know the temp going into the pre-warmed drum, I know the temp of the room, I pour the developer in, and I set the timer based on past negatives developed under the the same or similar circumstances for the intended process(es). Sometimes from memory, sometimes by referring to notes, sometimes I just go for it. And sometimes I miss and get negatives I can look at all day on a light table but are true beasts in a contact printing frame.

 

[Andrew O'Neill]

Nuts.

 

[Maris]

I just measure developer temperature always using the same laboratory thermometer and adjust the time according to the nice Ilford compensation chart. If the thermometer actually reads a bit wrong that error has been automatically taken care of in my initial film developing calibrations.
Maybe ordinary panchromatic large format black and white film is very forgiving but I find the amount of development is uncritical as long as it is enough or perhaps a little bit more. Likewise the amount of camera exposure can vary as long as it is enough or a little bit more.
The ultimate correction factor for accumulated small errors in the sequence of events that produce a negative is the use of modern variable contrast black and white photographic paper. If it's on the neg it can be rendered on the print.

 

[Sirius Glass]

And yet, the Ilford chart being discussed assumes a 1°C delta is equal to 2°F-- a 10% error right there (should be 1.8).

Further, looking at the chart, for 9 minutes, +/- 2°F @ 68°F is a minute's difference in time-- divide 60 seconds by 20, since there are 20 tenths in 2 degrees, and 1/10th of a °F should affect your time by 3 seconds (6 seconds for °C).

Extrapolating that to 15 seconds, the smallest interval most developing charts give, and it seems that any error below 0.5°F shouldn't really matter-- for 9 minutes of developing time, at least.

I think most people would be hard pressed to tell the difference.

As I posted the Jobo processor provides temperature readings to 0.1 degree C and some here a Photrio got their noses out of joint and made fun of my using interpolation to get the time down to seconds.

 

[mmerig]

You only need to be within+/- 1degreeC for the developing temperature; everything else is obsession.

Good advice. I adjust the time for 1 degree F tolerance, but know that the temperature probably drifts during development sometimes.

 

[Sirius Glass]

Good advice. I adjust the time for 1 degree F tolerance, but know that the temperature probably drifts during development sometimes.

How the equipment is set up the temperature may or may not drift. If the chemical bottles and the tank are in the same water bath with temperature control, then the will be very little or no temperature drift.

 

[MattKing]

Nuts.

Yes, but temperature controlled nuts!

 

[DREW WILEY]

Do trial runs with water only in the drum under typical process volumes and ambient air conditions. Read the precise temp of the solution in the holding bottles, and then immediately after draining out of the process drum, to determine the difference. That might seem to warrant shorter drum times rather than longer, but there more to it than that. In fact, short times means that the time of filling and draining itself becomes a bigger variable and harder to consistently control, especially with Jobo drums, which has a small opening. Tray processing get affected by the temp of fingers, as well as ambient air circulation above the trays. Just part of the learning curve. Eventually it gets routine just like everything else. But black and white darkroom work is way more forgiving than color. If you plan to do both, don't cut corners.

 

[Kilgallb]

For me, doing a large amount of 4x5 is a zen thing. No computers, just my darkroom and my music. I work hard to get everything just right. I guess for good results but more likely to relax after a day of CAD.

 

[Sirius Glass]

Do trial runs with water only in the drum under typical process volumes and ambient air conditions. Read the precise temp of the solution in the holding bottles, and then immediately after draining out of the process drum, to determine the difference. That might seem to warrant shorter drum times rather than longer, but there more to it than that. In fact, short times means that the time of filling and draining itself becomes a bigger variable and harder to consistently control, especially with Jobo drums, which has a small opening. Tray processing get affected by the temp of fingers, as well as ambient air circulation above the trays. Just part of the learning curve. Eventually it gets routine just like everything else. But black and white darkroom work is way more forgiving than color. If you plan to do both, don't cut corners.

I skipped the testing and set up the Jobo processor, let it come to temperature, stabilizing and letting the tank or drum plenty of time to come to temperature be for even thinking about the presoaking. For room temperature I will let it set for an hour; color after it reaches temperature I will let it sit for at least two hours. The circulation water needs time to temperature stabilize and the plastic tanks need more time.

 

[MattKing]

Stepping back a bit on this ....
Temperature is a variable that does affect results.
Temperature is also a variable that we can reasonably have some control over.
It is very useful to become familiar with how temperature changes happen, how quickly they happen, how we can control them and, most particularly, what and how much affect they have.
If we become reasonably knowledgeable about those things, particularly in our own darkrooms, we can reasonably comfortably take the necessary care with temperature, to the extent that our choice of processes require.
It becomes quite effortles if things are presictable.

 

[radiant]

Temperature is a variable that does affect results.

Everything affects everything. That is nothing new.

Question is: what real life effects does it have? Are your negatives ruined if you mess up with one degrees of celcius? Two? Five?

 

[250swb]

Obsessing about the exact time the last drop of developer is poured out of the tank is missing the point, the emulsion will still have developer in it, the time to obsess about is the point when stop bath is poured into the tank. And the most important aspect of obsessing about the exact temperature is that temperature is more important at the very start of the development cycle than at the end, especially in the normal home processing regime (excluding water bath and Jobo's etc.). Within those parameters we can still introduce our own habits which as long as they work are fine, like pouring the developer out to the exact second shown on the dev chart then take another ten seconds before you pour in the stop bath, so effectively you've developed the film +10 seconds. These things don't even need noting for your own use, they are your habits and they work, problems can arise if you assume your habits are everybody else's' habits.

 

[radiant]

Obsessing about the exact time the last drop of developer is poured out of the tank is missing the point, the emulsion will still have developer in it, the time to obsess about is the point when stop bath is poured into the tank.

I don't have any other proof than my own video, but I would argue that after 5 minutes the development slows significantly so it doesn't really matter if you develop the film for +-30 seconds. There is absolutely no visible or analyzable effect. If you are counting seconds to the pouring moment, please save yourself from it.

 

[tokam]

As @250swb has said, the developer remains active in the emulsion right up to the point that you saturate the film with stop bath. If you are going to be a consistent worker you should take this into consideration.

Regarding 5 minute and shorter development times. Even Kodak advises caution in this regard as you risk inconsistent and sometimes unpredictable results. When you also throw in a variation of +- 30 seconds which is 10% of the development times then this just plain sloppy technique. You may be able to get away with +- 30 seconds during 1 hour stand development and maybe this where you should stay for the meantime.

 

[radiant]

As @250swb has said, the developer remains active in the emulsion right up to the point that you saturate the film with stop bath. If you are going to be a consistent worker you should take this into consideration.

Regarding 5 minute and shorter development times. Even Kodak advises caution in this regard as you risk inconsistent and sometimes unpredictable results. When you also throw in a variation of +- 30 seconds which is 10% of the development times then this just plain sloppy technique. You may be able to get away with +- 30 seconds during 1 hour stand development and maybe this where you should stay for the meantime.

I didn't say 5 minutes is the total time of development. I wrote the development slows down dramatically after 5 minutes, or even before. I've seen it with my own eyes when developing by examination.

Have you ever tested the effect of 30 second difference during development? I bet everyone goes by the what is written and hardly any have tried playing in around with the developing. I think everyone should try it. By going by the instructions you only learn to go by the instructions. It benefits everyone to have hands on feeling how things actually work. Feels like stepping out of the matrix