Tmax-400/35mm with XTOL: Getting thinner negatives than before?

This old, now revived thread touches on a problem I encountered: Gradual decline of Xtol activity. In TMY-2 and 2-TMY it was more pronounced than with other film brands.
I had mixed Xtol powder with deionised water (battery water, straight from the shop). I assume people mentioning "distilled" water actually refer to deionised, too. Such "battery water" is not necessarily fit for drinking, as all kinds of germs can grow inside the ion exchange columns - and may release some offspring into the water... It all depends on the manufacturers standards, which I have never seen disclosed.
Upon above mentioned development issue, in that batch of Xtol I noticed a significant growth of barely visible slimy stuff, after about 4 months (storage: dark green 0.5 L PP and glass bottles, full to the brim, kept in the dark at 18-20°C). Upon inspection, similar slime was growing in some other bottles, too.
May be, this growth "eats" on the developer and gradually destroys it.
In such Xtol-stock, filtered and treated with a UV-striliser, no further growth was observed and activity remained constant over another ~4 months now.
In a not UV-treated control, a lot of slime has regrown and the developer has lost most of its activity.
Even if one could compensate for the low activity with extended development times (would be pure guesswork), I'd feel most uncomfortable soaking my films in such a contaminated concoction!

The Tmax films contain significantly greater amounts of iodine than other films. When these films are developed the iodine is released into the developer. Iodide ion has a powerful restraining action on development. So if you use these films (also Ilford Delta films) then a one-shot developer like HC-110 would be a better choice than a replenished system. Years ago when most B&W films were developed by automated machines iodide was removed by using a chemical to precipitate it from the developer. However the chemical used is highly toxic and the EPA has banned most uses for this element.

Thanks Matt and Gerald,

I am just starting with xtol replenishment regime and just wanted to confirm what I understood.

Will report any new experiences.

I have some user experience with your particular combination, and have not found that TMax or Delta films impact the developer negatively.
As a precaution, you could increase your replenishment rate. In any replenished system, you need to balance the amount of replenishing solution with your results. Ideally you should do test strips, and use a densitometer to evaluate developer activity, but in lieu of that it's best to keep a keen eye on the results. If activity tapers off you need to increase replenishment rate until you get normal activity again. That's the nature of the beast.

I was a medium volume user, and only used the developer for 5 years, with 1,000+ rolls going through, so I can't tell you from a lower volume, or a higher volume perspective, but my replenishment rate of (I think) 80ml liquid per roll kept my solution in very good shape, with mostly TMax 400 as my film of choice, with some Foma and Tri-X thrown in for good measure.

davedm said:

Thanks Matt and Gerald,

I am just starting with xtol replenishment regime and just wanted to confirm what I understood.

Will report any new experiences.

Click to expand...

Thanks Thomas,

I am low volume user, ~100 rolls/ year processing a mix of all traditional/t-grain films. I have a x-rite 334 sensitometer (with only green channel working). However, I have no access to a densitometer and hence I am unable to monitor strips. I have started at 70ml/min will see if I need to replenish more. Once I start printing, I plan to print test strips at a fixed exposure and visually match densities.