Straying away from 20C/68F when developing B&W film

drp · Dec 23, 2023

Hello,

I'm curious to know if there are any significant downsides to developing film from the standard 20ºC/68ºF temperatures? I've heard that if you increase the temperature, there's a likelihood of increased grain. Is that accurate? If so, is that regardless of the increase in temperature, say 24ºC? I know some developers don't require strict temperature control but just curious about the typical developers. Any other issues to note?

Thanks!

Ian C · Dec 23, 2023

So long as you develop your film at the temperature/time combination specified by film maker, there should be no difference in the result.

Most Kodak data covers 68ºF to 75ºF (20ºC to 24ºC). There is nothing special about 68ºF/20ºC. I think this oft-cited temperature is so often given because it is the assumed average temperature of a basement darkroom.

See the temperature time chart at the top left of page 3 in the Kodak F4016 PDF for T-Max 100 film for examples.

https://imaging.kodakalaris.com/sites/default/files/files/resources/f4016_TMax_100.pdf

Some film and developer combinations might be somewhat different, but in general are similar to the above table.

Don_ih · Dec 23, 2023

If you use an mq developer and lower the temperature too much, the hydroquinone will essentially stop doing its job well. There is also the possibility that, in a developer with more than one developing agent, the separate agents will gain unequal amounts of activity as the temperature rises (there's no good reason to think that is not the case), which would possibly change the characteristics of the developer (like maybe make more grain). But from 20 up to 24 degrees? -- probably not. You would need to significantly shorten your development time with such an increase, though. There are other problems with development times that are too short.

ic-racer · Dec 23, 2023

drp said:
Hello,

I'm curious to know if there are any significant downsides to developing film from the standard 20ºC/68ºF temperatures? I've heard that if you increase the temperature, there's a likelihood of increased grain. Is that accurate? If so, is that regardless of the increase in temperature, say 24ºC? I know some developers don't require strict temperature control but just curious about the typical developers. Any other issues to note?

Thanks!

The major downside is that processing temperature control with a heater won't work if your darkroom ambient temperature is above 20C. Cooling requires a refrigeration unit whereas heating only requires electricity and a resistance.

Doremus Scudder · Dec 23, 2023

Ilford's time/temperature conversion chart: https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Temperature-compensation-chart.pdf

drp · Dec 23, 2023

Thanks for the replies so far, everyone. I'm aware of Kodak's/Ilford's temperature conversion charts, I just wasn't sure if going to say 24ºC instead of the standardized 20ºC would cause any physical problems for the negatives as long as developing times aren't too short. For instance, that films develop better or have less grain at 20ºC than 24ºC. One unique film example is Kodak's Double X cine film that has its spec sheet list 21ºC as the proper developing time. Again, I wasn't sure if going a few degrees hotter like 24ºC or so would cause any obvious differences.

Alan9940 · Dec 23, 2023

I routinely develop my film at temps >20C because my indoor ambient temps are fairly high during much of the year. I've never noticed any degradation of the negative using several different developers--typical standard developers and pyro.

MattKing · Dec 23, 2023

drp said:
Thanks for the replies so far, everyone. I'm aware of Kodak's/Ilford's temperature conversion charts, I just wasn't sure if going to say 24ºC instead of the standardized 20ºC would cause any physical problems for the negatives as long as developing times aren't too short. For instance, that films develop better or have less grain at 20ºC than 24ºC. One unique film example is Kodak's Double X cine film that has its spec sheet list 21ºC as the proper developing time. Again, I wasn't sure if going a few degrees hotter like 24ºC or so would cause any obvious differences.

Motion picture film is designed to be processed by large, high volume labs that work with really narrow tolerances.
The datasheets are oriented toward the most likely use of the film.
Still films have datasheets that reflect users that require much more flexibility.
There may very well be special purpose still films - e.g. microfilm - that would suffer from non-standard usage, but general purpose still films need to be able to handle a range of development regimes.
Anything between 18C and 24C should not be a problem.
In my case, I always develop film at the ambient temperature. If that temperature isn't between 18C and 24C, I just wait.

albada · Dec 23, 2023

MattKing said:
In my case, I always develop film at the ambient temperature. If that temperature isn't between 18C and 24C, I just wait.

Impatient people like me keep a couple of liters of tap water in the refrigerator. When ambient is well above 20C, I'll place the beaker of developer into a cold water-bath (cold is about 5C) until the dev is down to 20C; then it's time to pour it into the tank.

Mark

Steve@f8 · Dec 23, 2023

As a grain lover I’m tempted to develop B&W at something like +30C, but have no idea how to adjust the times given in the Massive chart. Anyone tried hot development?

Craig · Dec 23, 2023

The only thing to keep in mind with higher temperatures is to not let the developing time fall below 5 min, as that can lead to uneven development.

Sirius Glass · Dec 23, 2023

I always adjust the development time for the ambient temperature which ranges for me from above 20°C to 24°C and I have never had a problem by following the manufactures' data sheets. Above that high temperature the development time is too short and then there a problems such as filling problems from too short development problem. That us the same problem discussed in post 11.

MarkS · Dec 23, 2023

Develop much above 80F and you risk the emulsion sliding off the film.
Develop much below 65F and you'll die of boredom while the film slowly develops.
Whatever temperature you choose, remember to keep all your solutions (including the wash) at a similar temp.
1-2 degrees F difference will be just fine.

dynachrome · Dec 23, 2023

In High School many years ago we used warm Dektol to develop film when we were in a hurry. The times were very short and the results beyond grainy but it was fun. The basement where I develop film is heated and air conditioned. If things get a little warm I put a few ice cubes in a small plastic bag and pour in a little water. I don't have to dip the corner of the bag into the developer for too long to cool things down. I do the opposite by using some warm water in the plastic bag. If I am diluting a developer 1:1 it's easy to get to the right temperature. I am usually in the 68-70F range.

cmacd123 · Dec 23, 2023

you do have to also check the film data sheet, as some will work at higher temperatures, but some are not hardened enough to stand the heat.

for Microfilm, I vaguely recall that one place I worked had a kodak PROSTAR tabletop Microfilm processor . which would do a 100ft roll in about 10 minutes, so would be hotter than 20C https://worldmicrographics.com/kodak-microfilm-processors/ (here it is from the manual found online
Read the developer temperature. If the temperature is not 37.8°C
±0.3°C (100°F ±0.5°F), repeat steps 1 through 6 until the
temperature stabilizes at the setpoint. ) the dryer was somewhat warmer -->
Adjust the dryer temperature control (if necessary) so the dryer
temperature falls within the acceptable temperature range of 38 to
52°C (100 to 125°F).

one item to watch is that if ALL the solutions are not the same temperature, you can get Reticulation on some films.

foc · Dec 24, 2023

cmacd123 said:
you can get Reticulation on some films.

In my experience, reticulation will occur only if there is a wide variance in temperatures, but it is best practice to keep all chemicals and wash water at a similar temperature.

Ian Grant · Dec 24, 2023

drp said:
Hello,

I'm curious to know if there are any significant downsides to developing film from the standard 20ºC/68ºF temperatures? I've heard that if you increase the temperature, there's a likelihood of increased grain. Is that accurate? If so, is that regardless of the increase in temperature, say 24ºC? I know some developers don't require strict temperature control but just curious about the typical developers. Any other issues to note?

Thanks!

When I lived in Turkey I regularly processed my films at 27ºC, that was the tap water and ambient temperature in our apartment. I found I could keep the whole cycle through to washing within +/- 0.2ºC, actually with no effort. Ideally you need to keep to within +/- 1ºC

Most modern films are well hardened so won't give the typical reticulation of films of the FP2/HP3 and earlier generation. But you can still get micro-reticulation, also known as incipient reticulation with temperature shock and this appears as increased apparent graininess of a film when printing, and more so scanning.

Ian

Ian Grant · Dec 24, 2023

Craig said:
The only thing to keep in mind with higher temperatures is to not let the developing time fall below 5 min, as that can lead to uneven development.

If that was the case then why don't we see uneven development of home processed C41 colour films or XP2 which are processed usually at 37.8ºC for 3 mins 15 seconds in the colour developer.

The only reason I've ever seen for not using short development times with B&W films has been inconsistent results, but with good temperature control that is not an issue.

Ian

Craig · Dec 24, 2023

Ian Grant said:
If that was the case then why don't we see uneven development of home processed C41 colour films or XP2 which are processed usually at 37.8ºC for 3 mins 15 seconds in the colour developer.

C41 was designed for that time and temperature, traditional B&W films and developers were not. Kodak has put that warning about non-uniformity on their datasheets for years, it must be there for a reason. Similarly, Ilford does not recommend any time as short as 3:15 or as high as 37°C for non C41 films.

MattKing · Dec 24, 2023

The warning about short development times relates to how relatively narrow the tolerances are with respect to timing and agitation when the development times are short. You can get great results with hand development and short developing times, but you need to approach timing and agitation with a higher degree of rigour than if times are longer.

DREW WILEY · Dec 24, 2023

I have a compensating development timer and water jacket probe, so often start out at 70F just in case there is some drift downwards. But I regard 75F as a risk threshold when it comes to edge frilling or worse. Depends somewhat on the specific film and developer; old outdated film emulsions tend to be more fragile in that respect. You also want all your solutions or trays at similar temperature.

Some developer ingredients like hydroquinone can change their activity disproportionately to other ingredients when you get too far out of bounds from 20C / 68F. Keep that in mind too.

Sirius Glass · Dec 24, 2023

MattKing said:
The warning about short development times relates to how relatively narrow the tolerances are with respect to timing and agitation when the development times are short. You can get great results with hand development and short developing times, but you need to approach timing and agitation with a higher degree of rigour than if times are longer.

Development times shorter than 5 minutes are more susceptible to artifacts related to tank pour in and tank pour out time and speeds, so I, as advised by Kodak et al, keep to longer development times. For me that means during the summer, developing earlier in the day, chilling the chemicals or running the air conditioner ahead of time.

loccdor · Feb 1, 2024

The hottest I've ever developed black and white is 27C (81F). Fomapan 400 @ 1600 in D-76 stock solution, for 12 minutes. It worked like a charm and was probably my most successful push processing - relatively normal contrast and grain. I think I just used the hot temperature to shorten the development time. It would have been quite long at 20C.

koraks · Feb 2, 2024

I've developed Fomapan 200 sheet film at around 40C in occasion. Worked fine; very fast. A few minutes for a steep curve and high density. No problems whatsoever.

gbroadbridge · Feb 2, 2024

I use 25C as my standard process temperature for more than 35 years.

It's simpler to warm up to 25C than to try to cool and achieve a stable 20C most of the year for me.

Straying away from 20C/68F when developing B&W film

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Straying away from 20C/68F when developing B&W film

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