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

BigMackCam · Sep 26, 2022

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

Paul Howell · Sep 26, 2022

If you can find an old copy of The Kodak Master Darkroom Dataguide on line, it has a development wheel, although set up for Kodak films from the 60s I found that by just setting the wheel to match the time for Foma at 68 degrees you can adjust the wheel to find the time for 65 degrees. I use it for Foma and other non kodak films to find temps above 20C or 68f as I live the desert and I have the opposite problem, higher water temps. I generally develop at 72 75 drees to better match the temp of my wash water. I checked on Foma 200, I get 6 minutes at 65 degrees.

Rick A · Sep 26, 2022

Why are you saying "approximately" 20c, don't you own a thermometer? As for lowering the temperature of your space to 18c and still not measuring the actual temperature of your chems you want to know what will happen. My darkroom is a constant 18c, I use a warm water tempering bath to bring my chems up to 21c for use(PMK), it only takes a few minutes to get there. I strongly recommend you buy an accurate thermometer and monitor your chemical temps. Developer is critical while stop, fix, and wash are good to go within a couple of degrees of the developer.

Pieter12 · Sep 26, 2022

Black and white film has plenty of latitude. Just follow the Massive Development Chart. There can be so many variables in processing film in a home darkroom, temperature is just one. You should have printable negatives.

MattKing · Sep 26, 2022

I always develop at the room's ambient temperature, which can be as low as 18C.
I too use the dial in the Kodak Darkroom Dataguides.
FWIW, that dial indicates 11 3/4 minutes for a 20C to 18C change, while the MDC calculator comes up with 12 1/5 minutes.
My only concern with going down to 18C is that some developers respond poorly to significantly lower development temperatures. I don't have enough Rodinal experience to know whether that is a concern for your choice.

BigMackCam · Sep 26, 2022

Paul Howell said:
If you can find an old copy of The Kodak Master Darkroom Dataguide on line, it has a development wheel, although set up for Kodak films from the 60s I found that by just setting the wheel to match the time for Foma at 68 degrees you can adjust the wheel to find the time for 65 degrees. I use it for Foma and other non kodak films to find temps above 20C or 68f as I live the desert and I have the opposite problem, higher water temps. I generally develop at 72 75 drees to better match the temp of my wash water. I checked on Foma 200, I get 6 minutes at 65 degrees.

Thanks for the tip on the Kodak Master Darkroom Dataguide - I'll look it up!

Rick A said:
Why are you saying "approximately" 20c, don't you own a thermometer? As for lowering the temperature of your space to 18c and still not measuring the actual temperature of your chems you want to know what will happen. My darkroom is a constant 18c, I use a warm water tempering bath to bring my chems up to 21c for use(PMK), it only takes a few minutes to get there. I strongly recommend you buy an accurate thermometer and monitor your chemical temps. Developer is critical while stop, fix, and wash are good to go within a couple of degrees of the developer.

Yes, I own a thermometer and I'm measuring the temperature of my chemicals. I say "approximately" because it's an analogue thermometer. Furthermore I can't account precisely for very slight (+/- 0.5 deg C?) increases and decreases in room - and, hence, chemistry - temperature during my processing. Since absolute precision of temperature readings isn't possible with my current setup, I consider them approximate (not, however, wildly inaccurate).

Per my OP, I'm now lowering the temperature of my space (my master bathroom, as I don't have a darkroom) to approximately 18 deg C, and my developing solution will be stabilised to room temperature - measured as before with my analogue thermometer.

I could use a warm tempering bath to bring the solutions up to approximately 20 deg C, but if I can work at the ambient room temperature instead then I'd prefer to do so for now. I'm not opposed to the tempering bath and better thermometer, but since I've been getting nice results thus far with what I'm doing and what I use, I'd like to see if I can continue that at ~2 deg C lower than before without additional steps or expense (if I can't, then so be it - I'll improve my approach and equipment).

Thank you kindly for the info on stop, fix and wash temperatures vs developer. Much appreciated

Paul Howell · Sep 26, 2022

I have worked in tropical conditions, Southeast Asia, Africa, now the American Low Desert, not by any means much experienced in cold temps, if your tap is cold I would extend wash time by 50%. I take it you scan your negatives rather than wet print?

BigMackCam · Sep 26, 2022

Pieter12 said:
Black and white film has plenty of latitude. Just follow the Massive Development Chart. There can be so many variables in processing film in a home darkroom, temperature is just one. You should have printable negatives.

Thank you - much appreciated!

MattKing said:
I always develop at the room's ambient temperature, which can be as low as 18C.
I too use the dial in the Kodak Darkroom Dataguides.
FWIW, that dial indicates 11 3/4 minutes for a 20C to 18C change, while the MDC calculator comes up with 12 1/5 minutes.
My only concern with going down to 18C is that some developers respond poorly to significantly lower development temperatures. I don't have enough Rodinal experience to know whether that is a concern for your choice.

Thanks - that's good to know, especially the concern re variance between developers. I appreciate some experimentation is required, and there are no guarantees here

Paul Howell said:
I have worked in tropical conditions, Southeast Asia, Africa, now the American Low Desert, not by any means much experienced in cold temps, if your tap is cold I would extend wash time by 50%. I take it you scan your negatives rather than wet print?

I've been using the "Ilford Wash Method", with pre-measured water that's stabilised to the same temperature (approximately ) as my developing solution.

I do indeed scan rather than wet print, but despite the flexibility (room for error?) that offers, I still like to produce decent negatives. I've been using the below reference as a guide for evaluating and improving the quality of my negatives:

http://www.aregeebee.net/negs/eneg.htm

Sirius Glass · Sep 26, 2022

I too adjust the black & white development time for the ambient temperature until it gets to the point around 24°C when development times start to drop below 5 minutes. There should be no problem with 18°C but use a good photographic quality thermometer. Look here ==>

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www.freestylephoto.biz

BigMackCam · Sep 26, 2022

Sirius Glass said:
I too adjust the black & white development time for the ambient temperature until it gets to the point around 24°C when development times start to drop below 5 minutes. There should be no problem with 18°C but use a good photographic quality thermometer. Look here ==>

Search Results

www.freestylephoto.biz

Thanks for that. I'd hoped that adjusting for ambient temperature wasn't out of the realms of sensibility

Thanks also for the link re thermometers. I'm currently using this one:

https://www.etonephoto.com/en-gb/pr...stainless-steel-wall-clip-for-film-processing

I've no reason to believe it's especially inaccurate, but without a calibrated, verified reference to compare it with, I have to make the assumption that the readings are "approximate"...

Sirius Glass · Sep 26, 2022

BigMackCam said:
Thanks for that. I'd hoped that adjusting for ambient temperature wasn't out of the realms of sensibility

Thanks also for the link re thermometers. I'm currently using this one:

https://www.etonephoto.com/en-gb/pr...stainless-steel-wall-clip-for-film-processing

I've no reason to believe it's especially inaccurate, but without a calibrated, verified reference to compare it with, I have to make the assumption that the readings are "approximate"...

That should serve you well. As I said I adjust development to room temperature.

pentaxuser · Sep 26, 2022

So 2 degrees C below the magic 20 C and no means of knowing if your thermometer is accurate to less than 0.5 C

No just kidding. Ilford for instance gives a temp/time conversion chart that covers quite a large range of temperatures. I strongly suspect it wouldn't do this if anything other than the "magic" 20 was a problem

I can only offer four words of advice to you: Don't worry, be happy

pentaxuser

MattKing · Sep 26, 2022

pentaxuser said:
I can only offer four words of advice to you: Don't worry, be happy

I would argue that that is 5 words
But the sentiment is excellent.
Even the 27 second difference I noted in my earlier post (Darkroom Dataguide vs, MDC) is probably not worth worrying about - as long as you use one or the other consistently.
An ambient temperature workflow means you can just leave everything on the counter for a decent bit and you will have achieved temperature control - and that includes wash water.

Sirius Glass · Sep 26, 2022

MattKing said:
I would argue that that is 5 words
But the sentiment is excellent.
Even the 27 second difference I noted in my earlier post (Darkroom Dataguide vs, MDC) is probably not worth worrying about - as long as you use one or the other consistently.
An ambient temperature workflow means you can just leave everything on the counter for a decent bit and you will have achieved temperature control - and that includes wash water.

Technically four words, one is a contraction and counts as one word.

Jay Schrotenboer · Sep 26, 2022

Only two words of advice
“Don’t Panic”
(Blame Mr Adam’s for the contraction, not me )

ags2mikon · Sep 26, 2022

I would not worry about 2 degrees c. Where it gets goofy is when your developer has more that one reducing agent and they have different coefficients of temperature. Then going to 16 c may start becoming a problem. But I would start testing with some unimportant rolls at lower temperatures just to be ahead of the game. Europe is going on a energy diet this winter and I hope and pray you all don't have a extra cold winter. I have added both kerosene and diesel heaters this summer because this could be a cold winter for all of us.

Sirius Glass · Sep 27, 2022

Jay Schrotenboer said:
Only two words of advice
“Don’t Panic”
(Blame Mr Adam’s for the contraction, not me )

Our fearless monitor will call that three words but he uses Adams' as the possessive form.

Huub · Sep 27, 2022

The Ilford site shows a temperature compensation table for film development: https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Temperature-compensation-chart.pdf

I keep a printed copy on my darkroom door.

And when it comes to thermometers: repeatability is more important then accurracy. It doesn't matter much if 20.0 c is actually 19.5 c or 20.5 c, but when it shows 20,0 c it should be the same temperature next week and next month. When you are happy with your negatives using your thermometer when it shows 18 or 20 c, it is good enough.

BigMackCam · Sep 27, 2022

ags2mikon said:
I would not worry about 2 degrees c. Where it gets goofy is when your developer has more that one reducing agent and they have different coefficients of temperature. Then going to 16 c may start becoming a problem. But I would start testing with some unimportant rolls at lower temperatures just to be ahead of the game.

Thanks. The majority of my photography experience is with digital; my film photography and home-developing journey only began in November last year, so I'm very much in the early stages. None of my rolls are important as such, and if I mess up a few of them it's no problem so long as I learn from the experience. Still, I'd like to tip the odds in my favour

ags2mikon said:
Europe is going on a energy diet this winter and I hope and pray you all don't have a extra cold winter. I have added both kerosene and diesel heaters this summer because this could be a cold winter for all of us.

We're already experiencing a rather cool start to Autumn here in the North East of England These last few mornings, when I've woken up around 4 - 5am the temperature indoors has dropped to around 15 deg C (it's currently 9 deg C outdoors), so I'm already using my natural gas central heating at the start of the day. Luckily, I have a pretty decent-sized wood-burning stove in the main living room, and for Winter I'm planning to use the central heating only for an hour or so at the start of each day (or in advance of a film processing session ), switching to the wood stove after that and spending most of my time in the living room... which reminds me, I need to place an order for plenty of seasoned soft and hardwood some time this week! It's not going to be cheap, but much more economical than natural gas right now

BigMackCam · Sep 27, 2022

Huub said:
The Ilford site shows a temperature compensation table for film development: https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Temperature-compensation-chart.pdf

I keep a printed copy on my darkroom door.

And when it comes to thermometers: repeatability is more important then accurracy. It doesn't matter much if 20.0 c is actually 19.5 c or 20.5 c, but when it shows 20,0 c it should be the same temperature next week and next month. When you are happy with your negatives using your thermometer when it shows 18 or 20 c, it is good enough.

Thanks for the link and your observation on consistency vs absolute accuracy of temperature; that makes good sense

koraks · Sep 27, 2022

BigMackCam said:
the temperature indoors has dropped to around 15 deg C

Funny you should mention this. To quote Matt earlier:

MattKing said:
going down to 18C is that some developers respond poorly to significantly lower development temperatures.

One thing that comes to mind is that hydroquinone (which is of course is NOT a part of rodinal) is pretty much inactive below 15C. In other words: developers can, and usually do, exhibit a non-linear temperature/activity relationship.

But...I agree with the sentiment put forth by @pentaxuser - within reasonable temperature limits, don't sweat it (pun intended). 18C will be just fine. Just extend development time a bit. How much? Well, the Ilford chart is a nice starting point; it has always worked for me when I was somehow too lazy to adjust temperature precisely. I'm aware of its shortcomings, but have never been brutally punished by them. Going below 18C is something I would try to prevent. Mind you - you don't really need to keep your room at the temperature you develop your film at! It doesn't cost all that much energy to dump e.g. 250CC of water in the electric water cooker and use that to make up your developer, stop and fix by mixing it with cold tap water. The main advantage of sticking to a standard temperature is that it's just less confusing that way. At least for me. Especially with a developer like Rodinal, it's very easy to mix it up at a standard temperature. Alright, it may drift 0.25C over the development time if your room is cold. Just ignore that effect and live happily ever after...

BigMackCam · Sep 27, 2022

koraks said:
One thing that comes to mind is that hydroquinone (which is of course is NOT a part of rodinal) is pretty much inactive below 15C. In other words: developers can, and usually do, exhibit a non-linear temperature/activity relationship.

Interesting... However, I don't do much of anything when my home is at 15C, other than wait for it to heat up! I certainly won't be developing film first thing on a morning when it's colder indoors. For one thing, the family bathroom (my processing workspace) is busy on and off until 9am-ish, by which time the house is warming up (if 18C qualifies as warm)...

koraks said:
But...I agree with the sentiment put forth by @pentaxuser - within reasonable temperature limits, don't sweat it (pun intended). 18C will be just fine. Just extend development time a bit. How much? Well, the Ilford chart is a nice starting point; it has always worked for me when I was somehow too lazy to adjust temperature precisely. I'm aware of its shortcomings, but have never been brutally punished by them. Going below 18C is something I would try to prevent. Mind you - you don't really need to keep your room at the temperature you develop your film at! It doesn't cost all that much energy to dump e.g. 250CC of water in the electric water cooker and use that to make up your developer, stop and fix by mixing it with cold tap water. The main advantage of sticking to a standard temperature is that it's just less confusing that way. At least for me. Especially with a developer like Rodinal, it's very easy to mix it up at a standard temperature. Alright, it may drift 0.25C over the development time if your room is cold. Just ignore that effect and live happily ever after...

I think I'll start with the Ilford chart or MDC's time / temp converter for the current ambient temperature, give it a go and see how I get on. If I can't get a pretty decent result within three test rolls, I'll revisit the idea of bringing my chemistry up to a 20C standard.

Thanks for the input

titrisol · Sep 27, 2022

A good digital thermometer is a god investment, they are very cheap these days
You can try a "meat" thermometer which work fine between -10 and +80C and sell for less than $20
To make sure is calibrated use a mix of water and ice, mix it well. Temperature should be between -0.3 and 0 C

The ILFORD chart works fine for developer, and as it was said washing becomes slower so using the ilford/Agfa method just wait for a few more seconds in the first steps, and minutes in the later steps.

ic-racer · Sep 27, 2022

Just start developing at 18c and adjust time based on the chart initially but tweak as needed so the negatives print well. If you like printing with #2 paper, then adjust times as needed.

ags2mikon · Sep 27, 2022

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.

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

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