What Evil lurks in a tank of X-Tol...Hmm?

mgphoto · Jun 30, 2006

Just need some help from the brilliant minds that frequent this forum.

I have a 3.5gal deep tank of Kodak X-Tol (stock) that I have been replenishing for exactly two years (It's 2nd anniversary was last week...no gifts please). I have always noticed that after leaving the tank alone for a few days or more, a thin dark film forms at the bottom of the tank. All it takes is a little stirring and the stuff seems to go back into suspension, and it has never appeared to cause a problem. So what is it? Bromide, maybe??

A little note about my replenishment. Fresh X-Tol is added as needed and about every six months or so, I remove 4 liters, dump the rest, clean the tank, filter the old developer I saved, and add that to a fresh 10 liters, bringing the tank back up to approx. 3.5gal.

Any insight would be appreciated.

-Mark

Ryuji · Jun 30, 2006

The black sediment, if it can be filtered out nearly completely, is most likely fine particles of metallic silver. During development, silver halide mostly from unexposed part of the film can dissolve into the solution, and the silver can be slowly reduced to metallic form. It sometimes happens on the wall of the vessel, or it can make sediment. It sometimes makes mirror surface as well.

If the sediment cannot be effectively filtered out by paper filter, it is most likely sensitizing or antihalation dye that came off the film. Dye molecules are larger than most molecules in the film or developer (except gelatin and other polymers), but they can go through paper filter. However, if allowed to set still, they can aggregate and make more "solid" debris at the bottom of tank. Most people probably observed this in a bottle of film fixers that are reused many times.

Bromide concentration in the developer certainly increases as you process more film in it, but bromide ion is very soluble and it won't make precipitates. It only slows down development, and it also may lose speed.

I'm pretty sure that when Zawadzki, Dickerson and Opitz came up with XTOL-type developers, they hoped that it would be a perfect solution for replenished tank applications, replacing T-MAX RS developers. It is a great pity that a few problems arose since then that prevented widespread use of XTOL for those applications.

eclarke · Jun 30, 2006

Hi Ryuji,
I have been using the simple ascorbic acid/metol developer I found on your site for my Tmax 100 as an alternative to Xtol and am very happy with it. Someone suggested to me the other day that the DS-10 and DS-12 were improvements on this and I would like to have your opinion. I also shoot Acros..hanks..Evan Clarke

eclarke · Jun 30, 2006

I mean..thanks..EC

Ryuji · Jul 13, 2006

eclarke said:
Hi Ryuji,
I have been using the simple ascorbic acid/metol developer I found on your site for my Tmax 100 as an alternative to Xtol and am very happy with it. Someone suggested to me the other day that the DS-10 and DS-12 were improvements on this and I would like to have your opinion. I also shoot Acros..hanks..Evan

Thanks for the nice words. DS-12 is an improvement for DS-2 in terms of keeping property and reliability, but the photographic effects are very similar. If you are happy with DS-2 and if you are willing to prepare a fresh batch each time of use, then you might want to do that way. DS-12 can be made in a concentrated form and it keeps well for months in closed bottles.

DS-10 was introduced as a new developer and I consider it to be an extension of XTOL. DS-10 is a terrible developer for slow films but it is an excellent developer for Plus-X, 400-speed and faster films. There are new improvements to DS-10 but the latest generation requires a few exotic ingredients and won't be useful even if I publish the formula. I'm working out with the manufacturer to make the developer available, and then try to do something about those who prefer to mix it at home.

David A. Goldfarb · Jul 13, 2006

Sixty-Eight Degrees lab in New York uses Xtol in their big Refrema dip-and-dunk processor. I've seen it with the lights on, and didn't notice any sediment, so I suspect it's got some sort of filtration system (or they had just cleaned and refilled the tank). Their website is at http://www.sixtyeightdegrees.com/

df cardwell · Jul 13, 2006

Keep the XTOL going.

A darkroom is no place for a brilliant mind.

.

Robert Brummitt · Jul 13, 2006

"What Evil lurks in a tank of X-Tol?"
Only the Shadow knows.
HAHAHAhahaHAHAha!

Ryuji · Jul 13, 2006

I believe in fog, rather.
(Actually, my new developer is slightly milky.)

srs5694 · Jul 13, 2006

Ryuji said:
DS-10 is a terrible developer for slow films but it is an excellent developer for Plus-X, 400-speed and faster films.

My apologies if you've already addressed this in other threads, but in what way is DS-10 a "terrible" developer for slow films? I've actually never tried DS-10, but I like DS-12 and DS-14, and sooner or later I'm sure I'll try DS-10, so I'd just like to know what sort of bad things I'd be avoiding by sticking to DS-12 or some other developer for my slow films.

Ryuji · Jul 14, 2006

DS-10 doesn't build contrast/density with some films like Pan F Plus and APX100. One possible way to help alleviate this is to use DS-10 at 1+2 dilution and 25˚C but I'd rather use DS-12 for those films.

Other than this, I see no problem in using DS-10 as a general purpose fine grain film developer. It works very nicely with 400-speed and faster b&w films.

Thomas Bertilsson · Jul 14, 2006

I used to work at a commercial lab, a small one, where the black & white dip & dunk machine was a seasoned tank of Xtol. I forget exactely when they replenished the tank, but there was all kinds of slush at the bottom of that tank. Produced some absolutely gorgeous negs, however.

I don't know exactely what that compound is. Do you see it negatively affecting the outcome of how the negs are processed? I never saw any. Keep that tank seasoned. The film processing individual at my old employer's took great pride in how well he maintained the tank that way, and that the results were better than fresh brew.

- Thom

Ryuji · Jul 16, 2006

Seasonded developer is slightly less active and requires a bit more development time and or temperature to reach the same contrast. However, the seasoned developer often give lower fog, and sometimes better tonality for pictorial uses.

The difference comes from the seasoning, rather than replenishment. If yo want to get the same effect at home darkroom without maintaining replenished developer, you can simply add seasoning to fresh bath of XTOL (or whatever) and use it one-shot. Use development time specified for seasoned/replenished deep tank processing. In case of XTOL, you can add 0.7g/L of KBr to stock XTOL and that's close enough to what Kodak seasoning procedure does.

The visible junk is most likely aggregate of dyestuff and other soluble macromolecules that came off the film, and oxidized developing agents. They don't affect image quality as long as they don't damage the image. Occasional filtering will do.

df cardwell · Jul 16, 2006

While adding Potassium Bromide to fresh developer comes close to the Kodak seasoning procedure, it doesn't accomplish the same things as a replenished system. But in a home darkroom, in a one-shot system, it can lead to some nice refinements.

.

What Evil lurks in a tank of X-Tol...Hmm?

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