Darkroom Advice: Kodak Dektol Working Solution

Here’s a “classic from the archive”, written back in 2010, when I was doing a lot more darkroom work. I wrote and posted this little write-up partially because there didn’t seem to be much clear information about Dektol online, and consequently, I think it’s served as a resource to many people over the years, so I’ve prioritized it as a page to update to the more modern version of the site. Hopefully it will be helpful to you too!

As part of my day job, I maintain the darkroom facilities at Montana State University. For the most part, these are traditional black & white darkrooms, and we made a decision to switch back to Kodak chemistry at some point last year (we were previously using a different chemistry, which worked great, but the instructors like the classic contrast of the Kodak chemistry). For our film processing, that meant we switched to D-76, a classic powder developer, for which there is plenty of information on using. When one mixes D-76, one mixes a stock solution, which is a sort of “storage” solution, and then dilutes it for use 1 part to 1 part with water, to mix the working solution. Why not save the trouble and mix the working solution to begin with? Well, the working solution will expire quicker, whereas the stock solution is more stable to store. Also, it can be more useful to keep the more concentrated stock solution on hand for processing higher speed films, since trying to develop something like a 1600 film at a normal 1:1 dilution would necessitate something like a twenty-minute developing time. Using the stock solution shortens that time to around ten or fifteen minutes (varying, of course, on the film).

Using various film developers with various types of film seems to be very well documented, and it seems like one can find charts and advice all over the internet. The problem I encountered, though, was what to do about making a Dektol working solution– the working solution used for print developing.

Following Kodak’s instructions, both available online and on the packages of Dektol, it was not problem to mix a stock solution. The trick was finding information about the working solution, which proved to be more esoteric, which is what motivated me to put this page up– perhaps it will save you a bit of time! As I said, Kodak’s online materials sort of overlooked what to do about making a working solution, but the forums at photo.net yielded some recommendations. One fellow (or fellow-ette) indicated that he (or she) used Dektol mixed 1:2 with water, another reported 1:3. Someone also mentioned that he or she had heard that Ansel Adams supposedly used it 1:9.

The forums were a good starting place, but knowing full well that what one reads on the internet isn’t necessarily true, especially from the relatively anonymous world of “the forum”, I utilized an asset that many youngsters these days might not have ready access to: I consulted a real-life “elder”.

Dan teaches the university’s first-year black and white darkroom classes, and has a couple decades more experience in the matter of working and stock solutions, so I consulted him the next time I saw him in the darkrooms. Dan was able to confirm the forum information: most people use Dektol in a working solution that is usually 1 part stock solution to 2 or 3 parts water. So, what we’re using in the darkrooms right now is a working solution of 1:2, and it seems to produce fine results.

If you came to this page looking for the short answer, here it is: use Kodak Dektol in a working solution mixed from one part stock solution and two parts water, if you, like me, don’t have knowledge of how things were traditionally done in the darkroom. I know there’s a lot of old hands out there who just know this stuff off the top of their heads, but for us twenty-somethings just getting into it, we need this sort of information written down somewhere!

Come to think of it, maybe I should check Wikipedia for any information on Dektol working and stock solutions. If such a page doesn’t exist, perhaps it would be good for me to make one. As for “how Ansel did it” when it came to using Dektol, I didn’t ask Dan about that. Did the Mighty Ansel even use Dektol? Beats me– I think there are plenty of acolytes out there to ask, though.

— Charlie, on May 1st, 2010

Dektol Working Solution Quick Facts

  • Mix your stock solution 1 part to 2 parts water. That is, one unit Dektol stock mixed with two units water.
  • Developing times for prints will be between 2 and 4 minutes, but go ahead and let the prints sit in the tray for as long as you prefer.
  • Why not mix the working solution in the first place? Well, it has a shorter storage life, and oxides quicker. In the tray, you can expect it to be good for at least eight hours.
  • In most cases, used (conventional) developer can be disposed of into the sink, since it can be treated as normal waste in most sewer systems. This may not apply if you have a septic system, and check your local water regulations to make sure that you’re in compliance with the applicable guidelines.

UPDATE, May 27th, 2010: I’ve noticed, checking the web visitation statistics, that several of the search terms that have landed folks on this page have been for things like “dektol developing times”, and I realized I left out that somewhat important bit. In the labs, we generally develop the prints “to taste”, meaning that we usually just let things develop until they “look right”, which of course can take a bit of trial and error under the safelights. One also has to factor in paper characteristics, like “dry-down”, where things will look darker when wet than when the print is dry. Anyway, we usually recommend a 2 to 4 minute developing time for prints in Dektol. It’s sort of like making scrambled eggs or something– just let them sit there and agitate them a little until they seem to look the way you like them.

Personally, I usually let prints hang out in the developer for about two minutes, at least using when using RC paper (I haven’t had enough experience with fiber paper to notice if it needs to be treated differently). I think one of the main things is to be consistent, so that your usual (print) development style pairs well with your usual (print) exposure style. Generally, if you like the way it looks (after it’s dry, and in normal light), then keep doing what you were doing. If it works for you, then that’s what matters. Like film development, temperature can be a factor as well, but I think most people work in conditions close enough to “room temperature” that they don’t fret about adding or subtracting times. Still, if you have a hot or cold darkroom (or hot or cold developer, at least), you might want to plan for longer times if it’s cold, or shorter times if it’s on the warmer end of things.

ANOTHER UPDATE, June 2nd, 2010: Alright, one more thing to mention that I think I neglected to make clear in the above: the reason one makes a Dektol stock solution and then dilutes it into a Dektol working solution later, instead of just making a big batch of working solution to begin with, is that the working solution has a useful life of around 8 hours. I heard 8 hours from somewhere, but experience also indicates that, at least in a lab context (and with the volume of three gallons of working solution we use per tray) the life of the working solution is usually good enough to last us through the day and more to the twelve-hour mark… but your mileage may vary. As it is exposed to air, the solution will gradually oxidize, and in the case of the print developer, take on more of a cola-looking appearance. I’ve never really tested the solution’s longevity when stored in an airless container (like those compressing darkroom jugs), so I can’t speak for the working solution’s stability when stored that way.

And lastly, I’ll go ahead and add a little info box to the top of this page that will hopefully condense this narrative into a bite-sized nugget. I’ll also mention disposal real quick: first, check your local water regulations. Whatever they say is what goes, so don’t take this as gospel applying specifically to your city, county, region, state, principality or climate zone. ‘Round these parts, developer (conventional black & white developer) can be digested in our municipal waste water facilities, so we drain-dispose our developer. We don’t drain-dispose used fixer– we run that through a silver-recovery unit (silver isn’t good to introduce into the water system, and is toxic to microorganisms– even beneficial ones) before disposing of it, but the other stuff like stop bath and hypo-clear is also drain-safe.