Temperature-correction of Paper development-time

DREW WILEY · Feb 6, 2022

I'm another Zone VI compensation timer guy. And other than checking the probe for scum build up once in awhile, and for any corrosion on the connections, it's been sufficiently reliable for several decades now. Too bad something that simple isn't made any more. But what everyone seems to be missing is that significant off temperatures might affect certain ingredients in developers differently than others. And that fact as well as others might easily amount to hue shift in the print, as well as how it's affecting by toning. That's a whole other layer to the problem than just nominal density change in the print. I happen to be pretty nitpicky about final image tone.

And markbau - I must still be a "beginner" after all these years, because I routinely tweak actual contrast via more or less development time, and without ending up with more overall darkness. Done it thousands of times with both graded and VC papers. But it is important to use high quality papers with enough silver in them to accommodate that.

Vaughn · Feb 6, 2022

When the room temperature dropped (no heat on the weekends), I used a water bath to keep the developer and all, up.
I ended up with a 3 minute development time with both Portriga Rapid 111 and Gallery...usually grade 3 for both...in Dektol 1:3. The time/dilution was suggested when TJ Cooper was my prof ('79 or '80) and I liked the results and stuck with it. Sometimes reducing the contrast with two-bath developing Selectol-Soft/Dektol.
I covered the developing tray -- the university darkroom was not that dark. The 1:3 dilution has handy to fill trays for the 16x20s nice and deep...and other students would not use it since they used the tray of Dektol 1:2 next to it. Much safer.

RalphLambrecht · Feb 6, 2022

albada said:
Most of us are aware that development-time of negatives should be adjusted based on temperature. And Ilford has a table of such times which are based on the assumption that time must be decreased by 8.8% per degree-C of temperature-rise.
The correction is 8.8% per degree for Ilford's *film*.
You may want to google for 'proportional development'. It's a way to determine the overall paper development time by timing the first appearance of light mid-tones and using that time as an indicator for what the tota development time should be.
Does anyone know what correction should be used for *paper*?

As some have pointed out, development of paper does *not* have a completion. Rather, after the most-exposed areas reach Dmax, the lighter areas continue to darken. In my recent experiment, this darkening was obvious both visually and in my densitometer measurements when I developed for 1.5 minutes compared with 1 minute. Therefore, to get consistent midtones and highlights, development must be consistent. And that means being careful about temperature. Hence my desire to know how to correct for temperature of paper developer.

Mark Overton

albada · Feb 7, 2022

RalphLambrecht said:
You may want to google for 'proportional development'. It's a way to determine the overall paper development time by timing the first appearance of light mid-tones and using that time as an indicator for what the total development time should be.

Ralph, this is the first time I've read about using the emergence-time of light tones in factorial development. In your excellent book, Way Beyond Monochrome 2e, you describe factorial development as being based on "medium to dark mid-tones" (page 341). Can you tell us more about your experience with using light tones?

Mark Overton

markbau · Feb 7, 2022

DREW WILEY said:
I'm another Zone VI compensation timer guy. And other than checking the probe for scum build up once in awhile, and for any corrosion on the connections, it's been sufficiently reliable for several decades now. Too bad something that simple isn't made any more. But what everyone seems to be missing is that significant off temperatures might affect certain ingredients in developers differently than others. And that fact as well as others might easily amount to hue shift in the print, as well as how it's affecting by toning. That's a whole other layer to the problem than just nominal density change in the print. I happen to be pretty nitpicky about final image tone.

And markbau - I must still be a "beginner" after all these years, because I routinely tweak actual contrast via more or less development time, and without ending up with more overall darkness. Done it thousands of times with both graded and VC papers. But it is important to use high quality papers with enough silver in them to accommodate that.

Perhaps we have different definitions of contrast. I have tried it too and all I end up with is a darker print.

Bill Burk · Feb 7, 2022

The trick is to make test strips at the same development time. The idea from William Mortensen is that highlights become more plastic.

albada · Feb 7, 2022

I am now aware of two sources of correction-factors for temperature of paper developer:

1. https://www.photrio.com/forum/threads/chart-for-paper-developing-time-temperature.45043/#post-649075 . This posting obtained the correction-table from Photo Technique magazine "a few years ago" (posting was Jan 2009). My calculations show that the table reduces development-time by 11.5% per degree-C of temperature-rise.
2. http://curtpalm.com/CompnTemp.pdf . Thanks to Bill Burk for providing this link! The programmer of the CompNTemp software appears to know how the Zone VI timer works, as his report refers to Zone VI paper and film. My analysis of his data shows that he reduces development-time by 11.2% per degree-C of temperature-rise. For film, he uses 8.7%, close enough to the 8.8% that I divined from Ilford's table.

That's two answers to the question I posed at the beginning of this thread. But can we believe that 11+% number? It seems too high to me, making me wonder whether both sources above got their information from the same source. I developed a print an hour ago in 23-degree developer (heat-wave today), and I used the 8.8% factor for film out of caution. If that 11+% is correct, then we really should be more careful about temperature of paper-developer.

Mark Overton

albada · Feb 7, 2022

markbau said:
Perhaps we have different definitions of contrast. I have tried it too and all I end up with is a darker print.

I suspect that both you and Bill Burk are correct. When increasing development time, everything gets darker, which means the H-D curve is stretched upward. Said another way, the H-D curve becomes steeper near the toe, and shallower near the shoulder. Thus, contrast of highlights increases and shadow-contrast decreases. An interesting test would be to print the same negative twice: (1) paper exposed and developed normally, and (2) paper underexposed and overdeveloped. I'll guess that in (2), snow and clouds will look better and shadows will be muddy.

Mark Overton

snusmumriken · Feb 7, 2022

markbau said:
Factorial development is only of any use when you are printing many prints from the same neg and want to keep the print densities consistent as the developer deteriorates.

I agree with this. But I don't agree that you can't see the emergence of dark tones unless your 'safelights' are unsafe. I tested mine on installation and had to turn them up to face the (white) ceiling, but now they are fine for the 5 min it takes to process a print, and I can still watch the progress of development. What I do find difficult is to judge precisely when a dark tone has 'appeared'. In their leaflet for Multigrade Classic FB, ILFORD say:
<< On correctly exposed prints with MULTIGRADE developer 1+9, the image will begin to appear at approx 20 seconds.>>
I do at least agree with this, but by the time I have made certain and glanced at the clock it is more like 23 or 25 sec, and I may have got distracted by the nice look of the print! A 5 sec error in noting 'appearance' would mean a 25 sec error in total development time.

ILFORD also say:
<<Development can be extended up to 6 minutes without any noticeable change in contrast or fog.>>
In all humility, my experience is at variance with this. I find that development beyond about 2½ min at 20 deg C darkens mid- and light-tones perceptibly.

Personally, I think the only answer to this without driving yourself mad is to use fresh developer (for critical sensitometric work, that might mean fresh developer for each print), at exactly the recommended temperature, and to use exactly the same development time for every print, agitating constantly. Then at least you have standardised everything you can within reason and any remaining variation is an inescapable part of practical printing. I check the temperature of my developer just before I expose the paper and correct if too cool (by balancing the developer tray on top of the room heater!). The ILFORD leaflet on Multigrade Developer advises against high temperatures, for which the developer was not designed.

pentaxuser · Feb 7, 2022

I wonder how well you can maintain the same print with time corrections based on the percentage per degree C mentioned and replenishing developer as per the Ilford recommendation? Pretty well I'd have thought. If 11% is more than is required and assuming that the real answer may be less then it wouldn't be that difficult to experiment by using 10,9 percent to find the exact percentage, assuming of course that a movement from say 11 to 9% would be enough to make a difference that matters.

pentaxuser

markbau · Feb 7, 2022

snusmumriken said:
I agree with this. But I don't agree that you can't see the emergence of dark tones unless your 'safelights' are unsafe. I tested mine on installation and had to turn them up to face the (white) ceiling, but now they are fine for the 5 min it takes to process a print, and I can still watch the progress of development. What I do find difficult is to judge precisely when a dark tone has 'appeared'. In their leaflet for Multigrade Classic FB, ILFORD say:
<< On correctly exposed prints with MULTIGRADE developer 1+9, the image will begin to appear at approx 20 seconds.>>
I do at least agree with this, but by the time I have made certain and glanced at the clock it is more like 23 or 25 sec, and I may have got distracted by the nice look of the print! A 5 sec error in noting 'appearance' would mean a 25 sec error in total development time.

ILFORD also say:
<<Development can be extended up to 6 minutes without any noticeable change in contrast or fog.>>
In all humility, my experience is at variance with this. I find that development beyond about 2½ min at 20 deg C darkens mid- and light-tones perceptibly.

Personally, I think the only answer to this without driving yourself mad is to use fresh developer (for critical sensitometric work, that might mean fresh developer for each print), at exactly the recommended temperature, and to use exactly the same development time for every print, agitating constantly. Then at least you have standardised everything you can within reason and any remaining variation is an inescapable part of practical printing. I check the temperature of my developer just before I expose the paper and correct if too cool (by balancing the developer tray on top of the room heater!). The ILFORD leaflet on Multigrade Developer advises against high temperatures, for which the developer was not designed.

I have a bit of a phobia for safelight fog. Over the years I've visited quite a few darkrooms and have been surprised at how bright they were. Upon testing the safelights were often shown to be unsafe. I once visited a celebrated printer and he tested by putting a coin on an unexposed sheet of paper! (I kid you not) I test for 8 minutes, (after exposing a sheet to get approx zone VIII. I do a 2 minute development for everything so including exposure the paper is not exposed to the safelight for any more than about 3-4 minutes. My easel area is so dark I cannot see the focuser or burning/dodging tools, I find them by feel.

I totally agree with your thoughts on print development times. I standardised on 2 minutes long ago. My developer (Ansco 130) cycles between 20 and 21C using a heat mat designed for home brewing beer. I have the probe in the developer and also a thermometer. I use Ansco 130 usually for 3 print sessions which typically means about 30 8 x 10s or equivalent. I did a step tablet test a few years ago and found that after 40 8 x 10s the developer was still going strong but decided that about 30 should be the limit. Of course if I don't print for a week or two the developer gets dumped.

Unless you are doing a big print run from the same negative I think factorial development is a solution in search of a problem.

RalphLambrecht · Feb 7, 2022

albada said:
Ralph, this is the first time I've read about using the emergence-time of light tones in factorial development. In your excellent book, Way Beyond Monochrome 2e, you describe factorial development as being based on "medium to dark mid-tones" (page 341). Can you tell us more about your experience with using light tones?

Mark Overton

sorry, I meant factorial not proportional development. I have used both, light and medium midtones, as a baseline;and both work unless the developer is too exhausted.

snusmumriken · Feb 7, 2022

pentaxuser said:
I wonder how well you can maintain the same print with time corrections based on the percentage per degree C mentioned and replenishing developer as per the Ilford recommendation? Pretty well I'd have thought. If 11% is more than is required and assuming that the real answer may be less then it wouldn't be that difficult to experiment by using 10,9 percent to find the exact percentage, assuming of course that a movement from say 11 to 9% would be enough to make a difference that matters.
pentaxuser

If you can measure the temperature only to 0.5 degree accuracy, your development could still be 4.5% to 5.5% out due to that error alone. Even if you have a digital thermometer with readout in 0.1 degree steps, I doubt the actual temperature of the developer solution will be consistent within that sort of accuracy across the entire tray and over time (including when you put a sheet of cold paper into it).

pentaxuser · Feb 7, 2022

snusmumriken said:
If you can measure the temperature only to 0.5 degree accuracy, your development could still be 4.5% to 5.5% out due to that error alone. .

Yes the maths are in that sense irrefutable and yet I wonder how much the print changes given that beyond the recommended development time given by llford things actually change when Ilford mentions 6 mins. One day I am going to develop say 4 prints from one neg keeping everything the same except dev at say 12 sec intervals, writing on the back the times then shuffle them and place them into a box. Look at each several days later and see if I can place each in the correct order

It may only be me and my poor judgement but I have doubts, having "overdeveloped" prints in the past by quite a number of seconds, whether I will be able to place them easily and accurately in order

pentaxuser

snusmumriken · Feb 7, 2022

pentaxuser said:
Yes the maths are in that sense irrefutable and yet I wonder how much the print changes given that beyond the recommended development time given by llford things actually change when Ilford mentions 6 mins. One day I am going to develop say 4 prints from one neg keeping everything the same except dev at say 12 sec intervals, writing on the back the times then shuffle them and place them into a box. Look at each several days later and see if I can place each in the correct order

It may only be me and my poor judgement but I have doubts, having "overdeveloped" prints in the past by quite a number of seconds, whether I will be able to place them easily and accurately in order

pentaxuser

I'm sure you are right about that. That's why I try to standardise what I can control, and accept that there will always be variability in the process outside my control. The OP's sensitometric requirement is more critical on the face of it, though I wonder about trying to do such things with greater control than is possible for the average darkroom user.

Timberwolf · Apr 27, 2022

This is my first post so if there is a better way to find an appropriate thread for this question, please inform me.
I am considering using a modified ID-62 "universal" developer for both film and paper. The only difference in my formula is a slight increase of benzotriazole and elimination of bromide. What is a good starting development time and dilution for film (4x5 HP5 in a small hard rubber tank), and also for paper (Ilford Classic)?

MattKing · Apr 27, 2022

Timberwolf said:
This is my first post so if there is a better way to find an appropriate thread for this question, please inform me.
I am considering using a modified ID-62 "universal" developer for both film and paper. The only difference in my formula is a slight increase of benzotriazole and elimination of bromide. What is a good starting development time and dilution for film (4x5 HP5 in a small hard rubber tank), and also for paper (Ilford Classic)?

Welcome to Photrio.
It seems to me that your question is novel, and deserves a thread of its own. Feel free to start it in this sub-forum. If you need help, feel free to ask.
I'd suggest a title like "How best to use ID-62 "universal" developer for both film and paper".

David Lingham · Apr 28, 2022

There is a very good article on factorial development in the darkroom technique book Creative Elements by Eddie Ephraums. On pp167 there is description of how it works in practice along with a factorial development chart, showing extended development times from factor x2 to x8 for any emergence time from 5secs to 180secs.

jnamia · May 1, 2022

Timberwolf said:
This is my first post so if there is a better way to find an appropriate thread for this question, please inform me.
I am considering using a modified ID-62 "universal" developer for both film and paper. The only difference in my formula is a slight increase of benzotriazole and elimination of bromide. What is a good starting development time and dilution for film (4x5 HP5 in a small hard rubber tank), and also for paper (Ilford Classic)?

Hi @Timberwolf
If you go to the resource tab you'll see articles and recipes

ILFORD ID-62

Ilford ID-62 A PQ developer for Films and Plates. Stock Solution Warm water (125° F or 52 °C) -----------750.0 ml Sodium Sulphite, anhyd -------------------50.00 gm Sodium Carbonate, anhyd -----------------60.00 gm...

www.photrio.com

I've never used ID-62 before but D-72 and use 1/dilution for dilution-minutes. ( 1:6 for 6 minutes, 1:10 10 mins &C ) as a starting point..

I also did a quick search, but didn't read all 8 pages maybe there is something useful there too?

Search results for query: ID-62

www.photrio.com

Doremus Scudder · May 2, 2022

In my experience with the papers I use these days (Ilford MG classic, Foma 111 in both VC and graded and Adox MC-110 that I'm out of now, but hope comes back soon - all fiber-base) extending print development time seems to have little effect on overall contrast, but does give an effective paper-speed increase, similar, if not identical, to simply increasing exposure.

I use longer developing times to make effective changes in the print that would be less easy to do by increasing print exposure. For example, I'll extend development 15 seconds - 1.5 minutes before I'll make a change in my base print exposure and have to re-figure all my dodging and burning times.

Best,

Doremus

Temperature-correction of *Paper* development-time

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Temperature-correction of Paper development-time