Developing B&W negatives at 18 deg C instead of 20... newbie questions

snusmumriken · Sep 27, 2022

I have never used Rodinal, so I will throw out a question for others to answer. You say that you leave the solution to stabilise at room temperature. If your tap water was pretty cold, that might be an overnight job, I guess. So my question is: Does a 1:50 working solution of Rodinal suffer from standing around for that length of time - for instance, does it oxidise?

Personally, I aim to develop at 22 deg C. My tap water is pretty cold in winter, so I use a water bath at about 40 deg C to get solutions (and tank) up to about 21.5 deg C, then change the water to a 22 deg mix. This needs a little kitchen skill because of the thermal reserve of the plastic containers. If in fact the solutions are a little off the 22 mark when I start, I adjust times as per the Ilford time/temperature chart.

I also keep a reserve of 22 deg water for the first wash after fixing, to cushion the shock between processing temperature and tap water, and thus avoid the risk of reticulation.

But having read the brilliant idea in post #25 above, I think I shall be looking out for a small dead refrigerator ...

Andrew O'Neill · Sep 27, 2022

There is absolutely nothing wrong with processing at 18C. I do it sometimes...even at 15C as couldn't be bothered to take the time and energy to heat up my darkroom to 20C. I've even left the tank in the fridge over night!

MattKing · Sep 27, 2022

snusmumriken said:
You say that you leave the solution to stabilise at room temperature. If your tap water was pretty cold, that might be an overnight job, I guess.

Leave the water out for a while. After it comes up/down to temperature, then you mix up your working strength developer.
A plastic or metal container for water will come to room temperature fairly quickly. If you use something like a pail, you will have enough for mixing stop bath and for at least the first part of the wash as well!

Pieter12 · Sep 27, 2022

ags2mikon said:
Here is something you can do if you have some wiring skills and is not real costly. When my mothers tiny cat food refrigerator failed, the compressor died, she went and bought another one. That was just what I needed a dead refrigerator. I removed the compressor and all the associated items and installed a line thermostat, a bulb holder for a 100 watt bulb and use it as a chemical warmer. I can set it to 38 degrees C and warm up my c-41 or set it for 22 degrees c and warm up my black and white. It takes very little electricity and does not take up much space. I bought the line thermostat on evil bay. I think that was about 40 USD. The wiring was all re used from the unit. With the surge in energy prices world wide we are going to be more adaptive. This is also something you could hook to a solar panel and run at zero cost.

A cooler would do the same if you can get your water to 22º first. Or maybe the light bulb trick, just put it in the cooler in a small fixture or old lamp.

BigMackCam · Sep 27, 2022

snusmumriken said:
You say that you leave the solution to stabilise at room temperature. If your tap water was pretty cold, that might be an overnight job, I guess. So my question is: Does a 1:50 working solution of Rodinal suffer from standing around for that length of time - for instance, does it oxidise?

MattKing said:
Leave the water out for a while. After it comes up/down to temperature, then you mix up your working strength developer.
A plastic or metal container for water will come to room temperature fairly quickly. If you use something like a pail, you will have enough for mixing stop bath and for at least the first part of the wash as well!

Yes, this is what I've been doing. I fill several re-purposed 2 litre plastic mineral water bottles with tap water. After a few hours (probably much sooner) it's at room temperature, after which I mix my solutions for immediate use, with plenty left over for Ilford-method washing. More recently, my final wash is with bottled distilled water which is stored at room temperature by default (plus a couple of drops of wetting agent).

ags2mikon · Sep 27, 2022

There you go Pieter12 trying to over simplify things.

250swb · Sep 27, 2022

If you have two less cups of tea or coffee a day you will have enough hot water to heat your chemicals to a proper temperature, or turn the heating down and wear a fleece and then boil a kettle. But second guessing reliable temperature ranges gets you into the area of saving a bit on the electricity bill and losing the value you've placed in your film. Which is more wasteful, processing a roll of FP4 badly or boiling a kettle? I rest my case.

MattKing · Sep 27, 2022

250swb said:
If you have two less cups of tea or coffee a day you will have enough hot water to heat your chemicals to a proper temperature

True.
With B&W, 18C is a proper temperature.

250swb · Sep 27, 2022

MattKing said:
True.
With B&W, 18C is a proper temperature.

I'm struggling to find that in the Massive Dev Chart with the OP's Fomapan 200. In fact there are very few film and developer combinations in the 18C range, not that anybody should be a slave to convention. But film emulsions are like exposure, there is a 'reciprocity' involved for processing at lower temperatures just as there is in making longer exposures, and I think the only answer is to experiment against a datum negative and then come back and say 'hey, look what I did!'.

BigMackCam · Sep 27, 2022

250swb said:
If you have two less cups of tea or coffee a day you will have enough hot water to heat your chemicals to a proper temperature, or turn the heating down and wear a fleece and then boil a kettle. But second guessing reliable temperature ranges gets you into the area of saving a bit on the electricity bill and losing the value you've placed in your film. Which is more wasteful, processing a roll of FP4 badly or boiling a kettle? I rest my case.

Thanks for that. Mercifully, I'm not concerned about the energy costs of one boiled kettle a day just yet... but I would be interested to know whether 18C is definitively an unacceptable / unwise temperature at which to develop reliably, or if it's just the case that it's not the most-commonly-used 20C standard, hence folks are (understandably) wary...

BigMackCam · Sep 27, 2022

250swb said:
I'm struggling to find that in the Massive Dev Chart with the OP's Fomapan 200. In fact there are very few film and developer combinations in the 18C range, not that anybody should be a slave to convention.

Isn't that because the most commonly used reference temperature is 20C? There aren't many film plus developer combinations for greater than 20C either, but I see a number of folks developing successfully at such temperatures. Do you feel the 20C references in MDC - combined with use of its time / temp converter tool (or Ilford chart on which I believe it's based) - are likely to be unreliable?

MattKing · Sep 27, 2022

I repeat - 18C is fine.
You can use the adjustment calculator on the MDC site (or the dial in the Darkroom Dataguide) to convert from the 20C times.
You would need to test if you intend to use something significantly lower - some developers are more temperature sensitive than others.

Craig · Sep 27, 2022

titrisol said:
A good digital thermometer is a god investment, they are very cheap these days

Digital isn't necessarily any more accurate than analog, it depends on the calibration. I bought a glass/ spirit type thermometer from a scientific supply place and it was surprisingly affordable. Actually made in UK and it was $7 CDN/£4.75.

RalphLambrecht · Sep 27, 2022

BigMackCam said:
Hi folks... I'm hoping for some advice from more experienced home developers - well, more experienced than me, which probably means most of you good folks!

I started shooting and home-developing black and white negative film late last year, though I haven't done a great deal of it yet (only half a dozen rolls or so). I've been shooting mostly Fomapan 200 at box speed, developing with a spiral tank in Fomadon R09 (~ "Rodinal") 1+50 @ approximately 20 deg C room temperature - using Massive Dev Chart timings (10 mins) and agitation (gentle inversions) - and achieving generally satisfactory - dare I say pleasing - results.

With the alarming increases in energy pricing here in the UK, I'm now maintaining the average temperature in my home closer to 18 deg C rather than 20 (it felt rather cool at first, but my family and I are used to it now ). I haven't yet developed any film since making this change, and I'd like to give myself the best chance of success when I do, using solution that's stabilised at room temperature.

For the first time, I've just looked at Massive Dev Chart's "Time/Temp Converter" tool and Ilford's Time/Temp Chart. Apparently, my 10 minutes development time at 20 deg C will increase to a little over 12 minutes at 18 deg C... but I'm drawn to MDC's warning:

"These conversions are approximate and are based on standard black and white film in normal developer. Films and developers vary widely so you should always test any time/temp combination prior to using it on important work"

None of my "work" is especially important - it's all hobby stuff purely for my own enjoyment and learning, and failure isn't a big deal - but obviously I prefer to succeed

So... after that long pre-amble... my questions to you more-experienced film developers are as follows:

1) Should developing at 18 deg C pose any significant problems?

2) How reliable do you find the timings in Massive Dev Chart's Time / Temp Converter tool?

3) Has anyone used the same combination of film stock - Fomapan 200 - and developer - Rodinal - at lower than 20 deg C, and if so, at what dilution / timing / agitation?

Many thanks in advance for any advice, opinions or thoughts on this - and apologies for any newbie errors (choice of forum, terminology etc.) in the above

developing at 18C will not cause a problem and the chart is fairly reliable. You can trust it for making a first attempt and then adjust to taste.

BigMackCam · Sep 27, 2022

MattKing said:
I repeat - 18C is fine.
You can use the adjustment calculator on the MDC site (or the dial in the Darkroom Dataguide) to convert from the 20C times.
You would need to test if you intend to use something significantly lower - some developers are more temperature sensitive than others.

Thanks, Matt. Significantly lower than 18C and developing film will be the last thing on my mind

MattKing · Sep 27, 2022

BigMackCam said:
Isn't that because the most commonly used reference temperature is 20C? There aren't many film plus developer combinations for greater than 20C either, but I see a number of folks developing successfully at such temperatures. Do you feel the 20C references in MDC - combined with use of its time / temp converter tool (or Ilford chart on which I believe it's based) - are likely to be unreliable?

FWIW, my 1940 Kodak reference handbook uses 65F (18.33C) as the standard.
With B&W, as long as you are within a fairly wide range, repeatability is more important than any particular target temperature. B&W is both rewarding and fairly forgiving that way.
With colour, it is different. That is because one is essentially developing three different parts of the emulsion at the same time (the three colours) and if you don't use the right temperature, they don't develop together in the same ways.

koraks · Sep 27, 2022

250swb said:
there is a 'reciprocity' involved for processing at lower temperatures

This is not an accurate comparison. Reciprocity failure works differently and has a different effect on a typical image than reduced developer activity. Especially with a deviation as small as 2C from the usual 20C it's perfectly feasible and easy to compensate for the lower temperature. There is no influence on tonal relationships as is the case in a reciprocity failure scenario.
The fact that 20C is the standard is pretty much just a coincidence; it might as well have been 18C from the get go. 20C just happens to be a convenient compromise between development time and ease of keeping processing chemistry at temperature in a typical indoor space in the temperate zone where most of the photography r&d happened to have taken place.
It's of course perfectly easy and viable also for OP to do his processing at 20Cbut there's nothing inherently problematic if he wants to do it at 18C. No need for any Fear, Uncertainty and Doubt.

BigMackCam · Sep 27, 2022

Thanks to everyone for your kind, informative and interesting feedback. Very much appreciated.

I'm going to try developing at my ambient room temperature of 18C with the MDC time / temp converter (or Ilford chart) compensation for now, and will see how I get on!

Pieter12 · Sep 27, 2022

The Massive Development Chart app has a time/temperature conversion for each developer/film combination. Also, I haven't processed any in a while, but I think Bergger Pancro 400 is recommended to be processed at 24ºC when pushed.

Mick Fagan · Sep 27, 2022

Temperature Coefficient of Developers

The Influence of Temperature

As is the case with most chemical reactions, and photographic is a chemical reaction, the rate of development depends upon the temperature. The higher the temperature of the developer the more rapid and energetic will be the progress of development. This rule holds good for all developer substances but the actual degree of acceleration for a given rise of temperature varies with the different developers.

The increase in speed of development with an increase of 6ºC. is taken as the Temperature Coefficient of the developer. For example if we find that a particular developer works twice as quickly at 24ºC. as it did at 18ºC. then we say that it has a Temperature Coefficient of 2. A rough guide to the three main types of developer are; Temperature Coefficient of 1.8 for standard MQ developers, 1.6 for fine grain and 2.3 for super fine grain developers.

13ºC MQ 10 min, Fine Grain 19 min, Super fine grain 50 min.

18ºC MQ 6 min, Fine Grain 12 min, Super Fine Grain 25 min.

24ºC MQ 3½ min, Fine Grain 7 min, Super Fine Grain 12 min.

Developing by Jacobson and Jacobson, eighteenth edition, updated 1980, page 72

The above is almost word for word, with slight abbreviation.

mshchem · Sep 27, 2022

BigMackCam said:
Yes, this is what I've been doing. I fill several re-purposed 2 litre plastic mineral water bottles with tap water. After a few hours (probably much sooner) it's at room temperature, after which I mix my solutions for immediate use, with plenty left over for Ilford-method washing. More recently, my final wash is with bottled distilled water which is stored at room temperature by default (plus a couple of drops of wetting agent).

You should be absolutely fine at 18°C and your washing method should be fine. I use purified water and a bit of Kodak Photoflo, if you are using a wetting agent you need enough to change the surface tension of the final rinse.
Matt King has a recipe for diluting Photoflo with alcohol that makes it easier to measure and handle in small doses.

MattKing · Sep 27, 2022

mshchem said:
Matt King has a recipe for diluting Photoflo with alcohol that makes it easier to measure and handle in small doses.

Indeed, I do: https://www.photrio.com/forum/resources/making-and-using-a-kodak-photo-flo-stock-solution.396/

snusmumriken · Sep 28, 2022

MattKing said:
Indeed, I do: https://www.photrio.com/forum/resources/making-and-using-a-kodak-photo-flo-stock-solution.396/

That's clever, but there is another way. This is what I use, a 1ml plastic disposable syringe attached to a 1ml plastic disposable pipette via surgical tubing. Anyone in the medical/veterinary profession should be able to provide these items. Apologies for the rubbish picture.

MattKing · Sep 28, 2022

snusmumriken said:
That's clever, but there is another way. This is what I use, a 1ml plastic disposable syringe attached to a 1ml plastic disposable pipette via surgical tubing. Anyone in the medical/veterinary profession should be able to provide these items. Apologies for the rubbish picture.
View attachment 317503

I disagree with the "rubbish" characterization - it is a hockey themed self -portrait!

destroya · Sep 28, 2022

I do a lot of BBQ and have a smoker. I use a digital thermometer, for which I bought an extra probe that I use for chemistry only. very accurate and easy to use.

I agree with the massive dev chart idea. here is the link. I use it all the time.

Massive Dev Chart Film Development, Film Developing Database

www.digitaltruth.com

john

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