View Full Version : use developer dilution to tame high water temps?

Mark Sampson
11-Aug-2016, 14:46
Here's a new one to me after forty years in the darkroom. The water temp where I live now is at 80F. I have a lot of exposed 4x5 FP4+ film, which I will develop in Pyrocat-HD, using a 12-sheet Nikor tank (in numerous batches of course). I've done this successfully for several years, but the ambient water temp has never gone above 75 until now. So the calculations... show a dev time of 4'06". I wouldn't do that short a time in a tray, much less in a daylight tank with its long fill/dump times. So it occurs to me...

Can I use a higher-than-normal developer dilution to increase the development times to a reasonable, and repeatable, length?

My current dilution is 1:1:100, standard I guess. And of course it's important to keep the processing chemicals at close to the ambient wash water temperature. Chilling the chemistry is not really an option.
Is it feasible to go to, say, 1:1:200 and increase the dev time? I suppose there are two concerns here.
1) would there be enough developing agent to get to a normal printing density?
2) how would you calculate an increased time?
I have some exposed, non-project film that I had planned to use to calibrate the process before developing important film. But I wonder if anyone has tried this approach with any success? I don't want to spend half a box of film, and many scarce hours, testing this approach if I can pick your collective brains.
Ideas, anyone?

11-Aug-2016, 15:09
I did a project requiring very dilute developer a few years ago. Since my tank is of limited size, I changed the developer in the tank up to six times.

This shows measuring and diluting the solution between six bottles. The correct processing time was established via trial and error. Lots of it, as I found my control strips processed faster (when processed alone) than the keeper negatives.

David Schaller
11-Aug-2016, 16:57
I'm interested in this too, specifically PyroCat, for a different reason -- large N minuses.

Kevin Crisp
11-Aug-2016, 17:02
It is sound in theory if you don't overdo it. Due to high temps I went to my own dilution of HC110 years ago as I wanted to keep development times above 4 minutes in the summer. It is more dilute than the standard 1:31 "B" dilution. It didn't take much testing, I just made a negative developed normally, then a second identical exposure, cut in strips with longer and longer times in more dilute developer until I had a match. I use slow constant tray agitation so no chance I'd stray into accidental stand development + my dilution didn't need to be hugely more than normal.

Jim Jones
11-Aug-2016, 18:20
I've developed T-Max film in T-Max developer in trays and tanks at normal dilutions up to 85 degrees with no problems. Of course that's with a pre-wash.

11-Aug-2016, 18:56
Why not just keep a couple of bottles of water in the refrigerator? Mix the water from the fridge with water from the tap and off you go.


Jim Andrada
12-Aug-2016, 01:48
I put a couple of frozen bottles of water in the Jobo. Works well. Sometimes need to change them out part way through. Or maybe I should just shoot C-41 in the summer.

12-Aug-2016, 02:28
I regularly process at 27C (just over 80F) when in Turkey, that's the water temperature in the summer. I'm also using Pyrocat HD and my times are nowhere near that short,

15min @20C or 9:15 @ 27C that's in Jobo 2000 (inversion) tanks.


neil poulsen
12-Aug-2016, 03:26
Is the water any cooler in the morning? Mine is, so I develop film then. I keep my temperature at 70 degrees F. If needed, I get some ice from the fridge to maintain the proper temperatures. I use a Zone VI, compensating developing timer that corrects for changes in development, if I drift away a bit from 70 deg. F.

I'm no whiz at developer chemistry, etc., but I remember reading the following in Ansel Adams books. Addressing your question, it depends on what developer that you're using. If it includes both metol and hydroquinone, then it's not a good idea. The two change their fundamental characteristics differently with a change in temperature. It's not just an increase in activity. Metol activity behaves as expected with changes of temperature.

However, activity for hydroquinone behaves disproportionately with changes in temperature. It has almost no activity below 55 deg.F. However, it becomes excessively active above 75 deg F. So as temperature changes, developers containing both these active ingredients fundamentally change their properties. Adams also comments that at high dilutions, prints developed in Dektol take on a muddy quality. Seems like it would be the same for film.

12-Aug-2016, 03:49
I had this problem when I lived in a place where the water pipes were in the roof. I was using Efke film and had reticulation problems if I chilled the developer but used other chemicals at room temperature. I went to more dilute Pyrocat and various minimal agitation schemes to develop at 80F. The need for minimal agitation was also required to control the very high SBR where I lived.
I luckily had a corner of a building that, in the late afternoon, gave me a complete range of zones and made an excellent test site. I had to do a good bit of experiment ion to find appropriate development times, and like Ian, my times were not nearly as short as yours.

Mark Sampson
12-Aug-2016, 14:44
I've started testing; will report back when I have the answer. Thanks to everyone who has commented so far!

12-Aug-2016, 22:20
The old Kodak formula books say you can use regular developers like D-76 up to 90F, by adding sodium sulfate. There's a bunch of info in the old Kodak data books for "Tropical Development " start with prehardener, modify the developer, longer stop bath times, hardening fixers and post hardening. I'm not sure how relevant all the hardening baths are, with modern films. Definitely would want to make sure you keep solutions close to the same temperature throughout the entire process. .

Cold water from the fridge sounds easy to me.
Best Regards Mike

Doremus Scudder
13-Aug-2016, 11:00
The problem is not the water temperature per se, rather the short developing time. Adjusting developer dilution should help here.

When working with extreme developer dilutions, it is important to ensure you have enough stock solution for the volume of film you are processing. This might mean a larger total volume that you are currently working with. I've not tried Pyrocat, but I would imagine that diluting, say, 1+1+150 might slow it down enough to get your times more manageable. Check out Sandy King's website and read what he has to say about dilutions. I found this very quickly from http://www.pyrocat-hd.com/html/mixing.html

"All of the Pyrocat formulas are acutance developers that give good pictorial rendition when used at dilutions of 1:1:100 to 2:2:100 with normal agitation. When used at higher dilutions with reduced agitation they become high acutance developers with very pronounced adjacency effects."

And, of course, you'll have to test for your development time. However, I've had good luck "guesstimating" starting points with the following: half-strength = a doubling of the developing time. With 1+1+150 I might try 150% of the normal developing time as a starting point.

Hope this helps,


13-Aug-2016, 11:24
I develop in a Jobo ATL-3 and use HC-110. Normally I develop at 20C because the ground water is usually much lower and with the Jobo, it is easier to raise the temperature rather than lower it. I take a few weeks hiatus from development in the hottest part of the summer. However, this year, I am really twitching to develop a recent batch and the groundwater has hit almost 24C. So I am going to have to recalibrate and I will be facing some of the issues mentioned here.

My shortest development times will likely be under 5' so I am going to have to increase the dilution. In order to maintain the minimum amount of developer per sheet, there will be greater volume in the tank and perhaps fewer sheets per session. I don't like to run the Jobo absolutely full simply because it is getting old and I don't want to wear out the motor.

All of this is not that big a problem. I am just impatient. I live in Canada and the water temperature will be well under 20C in the not too distant future!

Stephen Thomason
13-Aug-2016, 12:22
You may want to check your calculations again. From the MDC that recommends 18 minutes @20C for FP4+ exposed at ISO100, 27C would give 8 minutes 56 seconds. That is for Pyro at 1+1+100. That should be easily doable.

13-Aug-2016, 21:11
My understanding of developer temps is that the emulsion thickness expands to many times it's thickness (esp in the developer), and allows greater diffusion of dev into the emulsion the more swollen it is... And swells more the warmer the solutions... So dev time is based on this rate of diffusion that allows greater activity/penetration the warmer the temp is... (And >80deg it can swell past the point where the swollen upper layer of the emulsion will not shrink back to register exactly with the exposed grain areas lower in the emulsion thickness, resulting in un-sharpness, and in worst case, (if it breaks up) classic reticulation, hence all of that hardening required with tropical/warm weather developers/developing...)

Some very dilute formulae will work under 80deg to cut your dev time, but by the time you wire it in, the leaves may be falling in your locale... You might save the important film processing for a few weeks from now...

Steve K

14-Aug-2016, 01:23
You may want to check your calculations again. From the MDC that recommends 18 minutes @20C for FP4+ exposed at ISO100, 27C would give 8 minutes 56 seconds. That is for Pyro at 1+1+100. That should be easily doable.

I'm not sure how you get to that time, temperature coefficients differ depending on the developer, and particularly the developing agents, my experience with Pyrocat HD is that 18 mins @ 20C is equivalent to 11 mins 8 seconds @ 27C. That's based on approx 10 years of using Pyrocat HD here in the UK and Turkey and a variety of films.


Stephen Thomason
14-Aug-2016, 11:15
Ian, the time was from the Massive Development Chart time/temp conversion calculator - I am relatively sure that it is pretty much just a straight line function.

I would greatly appreciate it if you would share your experience with PyroHD at various temps - it would be most helpful to me - Summers here in coastal South Carolina are a bit on the warm side also. My tap water yesterday was 28C.


14-Aug-2016, 11:45
My water here in coastal Georgia is 78F. I've had good experiences with Pyrocat and conventional 400 speed films - Tri-X, Hp5, even old Forte 400 from the freezer at 15-minutes with 1-minute initial agitation and 10-second agitations at 5 and 10-minutes.
I should add that I have a huge SBR here and use this method for some compensation.

Mark Sampson
30-Aug-2016, 19:00
Thanks everyone!
I chose a simple solution; every water pitcher in the house filled and into the fridge. when 68F is reached, begin. Normal dev time in the Nikor tank is about 11 minutes; N-1 about 8.5. Washing is accomplished with the old Leica recommendation of five changes of water. Temp varies a few degrees from start to finish, but the negs look good. The project is 50% processed now, the duplicate negs will have to wait until next week. In a way, I enjoy using such low-tech methods; quite a change from my Kodak days. Of course the prints will tell the real story, but they are month off at least.