Ian, Sal, this comes up occasionally with respect to mixing XTOL. What I've never understood is - XTOL contains an Iron sequestering agent. So why would a small amount of Iron in the water be a serious problem? I can see how it would be a problem with home-mix ascorbate developers, but it shouldn't be an issue with XTOL.
Also - Sal - regarding steam distilled being better than deionized for XTOL, actually I recall Gerald Koch saying it could potentially be the other way around if the steam distilling apparatus introduces Iron into the water.
Just thought I'd throw that extra wrench into the XTOL/water quality debacle.
All the reports of rapid failure were in the early years of Xtol production, Kodak must have made it more robust. Xtol keeps just as well as any other powder developer.
I've personally never had it fail on me. For a while I thought maybe there was something not quite right about how I was mixing it (using either deionized or distilled water) because my development times with TMax films were always longer than Kodak's indications. But no matter what I changed I always got the same results so I stopped worrying about it.
...regarding steam distilled being better than deionized for XTOL, actually I recall Gerald Koch saying it could potentially be the other way around if the steam distilling apparatus introduces Iron into the water...
It's difficult to imagine that the cold side of a distillation process (condensing steam) might introduce more iron into resulting water than a deionizing plant would. In either case, iron levels have to be orders of magnitude lower than what comes out of some taps.
I've never had an XTOL failure either. Steam distilled water is sold here in grocery stores at $3 for a 2-1/2 gallon container. Compared to the cost of everything else in photography, that's noise level. I see no reason not to keep using it for mixing/diluting XTOL and other powdered developers, diluting liquid developer/fixer concentrates and mixing Photo-Flo rinse solutions. Ultra-cheap insurance, especially where film is concerned.
We use in-house deionized water in the laboratory I work at. One thing to keep in mind with DI-water is that it will rust and pit stainless steel over time. Because the mineral ions are removed from the water it tends to pull ions off the metal, resulting in the pitting.
I've only processed a couple of rolls of film so far since I'm just restarting the whole film process, but I mixed up my ID-11, stop, and fixer as well as washed with filtered water from the tap with no issues that I could see. We just have one of the under-the-sink RO systems that removes most of the minerals. I figured I'd try that first before having to buy and store bottles of distilled.
To clarify my post on distilled water. If the condenser portion of the distilling apparatus is made of metal such as copper or iron this will introduce these ions into the water. Ascorbate is very sensitive to these ions due to the Fenton reaction. This is why Kodak uses a chelating agent DTPA in Xtol
Last edited by Gerald C Koch; 05-09-2013 at 05:24 PM. Click to view previous post history.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
It's not smart to use lead solder in your moonshine still either. But correct distilling is still going to give the cleanest water. Reverse osmosis
is for removing organic contaminants to create drinking water from whatever; some chemicals might get thru anyway. It's a semi-permeable
membrane system, to phrase it generically. Or you could passive filter things with a portable water purifier system - still wouldn't remove
everything. A lot depends on where you live and what the tap water is like. Here we get good snowmelt from clear across the state, so the
water quality is excellent. A few miles inland they get treated river water that is essentially over-chlorinated swimming pool water with a cocktail of agricultural runoff, incl trace amts of all kinds of pesticides. Dry climates can have very hard water with quite a bit of alkali. I hesitate to say where some of our highly advertised bottled water comes from. A least one brand is bottled at a superfund site, because nobody is actually allowed to live there anymore! The spring is some distance away ... but it still makes you want to think twice!
While not disagreeing remember that Kodak themselves don't actually specifical recommend using Distilled or Deionised water with Xtol in their Data-sheet. Traces of Iron will cause severe problems with fixers where the Iron and Thiosulphate form a fast acting bleach. I have had minute Iron particles in water way back in the 70's long before Xtol.
Why Kodak doesn't suggest to use distilled water only?