Is XTOL diluted 1:3 or more still risky? Fix with additional DTPA?

The latest film developing cookbook implies as much, remarking that Kodak has stopped giving developing times for dilutions greater than 1:1. But it recommends Xtol at 1:3 to 1:5 or even 1:10, at which point it performs somewhat like a compensating non-solvent developer, though with still impressively fine grain and greater speed; more of an S-curve and better mid-tone gradation.

First of all, the authors recommend a test that sounds a bit trickier than one's typical hypo check:

1. Expose fresh photographic paper to room light,
2. Put a drop of Xtol on it
3. Wait 30 seconds.
4. Put another drop of Xtol on it.
5. Wait 30 seconds.
6. Rinse and fix and wash and dry (but no developing beforehand?)

"The first spot should be dark grey and the second one medium grey."

It doesn't describe what failure looks like, which is a bit unscientific of them.

So I'd be thrilled to learn that XTOL is now flawless and this test is no longer needed?

The authors hypothesize that XTOL may fail when its level of DTPA is no longer strong enough to counter the detrimental effect of water or chemical impurities. It unhelpfully recommends adding more DTPA to prevent developer failure, but doesn't inform the reader how much, as if assuming all of us are experienced chemistry grads with an innate feel for chemical ratios.

As published, the Xtol recipe contains 1 gram DTPA. So is adding "more" an amount like, say, another 1 gram? Or more like 0.05 grams?

What XTOL recipe?

You can dilute XTOL, just increase the volume. I developed a lot of film using XTOL 1:1, one shot in Paterson tanks years ago.
These days I use XTOL straight in a Jobo. One shot.

ame01999 said:

The authors hypothesize that XTOL may fail when its level of DTPA is no longer strong enough to counter the detrimental effect of water or chemical impurities.

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It's not just that. It's also the sulfite concentration that drops to 25% of what it normally is in 'straight' XTOL. I mix my own XTOL clone and when experimenting with this, I noticed that the developer becomes *very* unstable once you reduce sulfite levels to lower than 50% (equivalent to 1+1). At this point, the developer tends to come out noticeably oxidized at the end of a regular development run (5-10 minutes), whereas it is perfectly clear and colorless after development (and long, long thereafter) under normal conditions.

I'd be very suspicious of the stability of XTOL in such dilutions. I'm sure it'll still work, but I'm not sure how dependable it is.

I used XTOL (and now Adox XT-3) a lot at 1+1 and 1+2, mainly for economy/environmental reasons and slightly sharper grain - never had a problem.

I do mix it with demineralised water though, and use demineralised water for dilution just before the developing session.

costs very little (0.10 to 0.20 EUR per roll) and seems simpler and safer than adding DTPA.

mshchem said:

What XTOL recipe?

You can dilute XTOL, just increase the volume. I developed a lot of film using XTOL 1:1, one shot in Paterson tanks years ago.
These days I use XTOL straight in a Jobo. One shot.

Click to expand...

There is a recipe attached to the patent application.

koraks said:

It's not just that. It's also the sulfite concentration that drops to 25% of what it normally is in 'straight' XTOL. I mix my own XTOL clone and when experimenting with this, I noticed that the developer becomes *very* unstable once you reduce sulfite levels to lower than 50% (equivalent to 1+1). At this point, the developer tends to come out noticeably oxidized at the end of a regular development run (5-10 minutes), whereas it is perfectly clear and colorless after development (and long, long thereafter) under normal conditions.

I'd be very suspicious of the stability of XTOL in such dilutions. I'm sure it'll still work, but I'm not sure how dependable it is.

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Thank you, this is extremely helpful. I just don't know the practical implications of what it means to say the developer solution isn't "stable," as long as development still works, as you note. Do you mean the results might be inconsistent, or that one day you might just get ruined negatives? Thanks!

dokko said:

I used XTOL (and now Adox XT-3) a lot at 1+1 and 1+2, mainly for economy/environmental reasons and slightly sharper grain - never had a problem.

I do mix it with demineralised water though, and use demineralised water for dilution just before the developing session.

costs very little (0.10 to 0.20 EUR per roll) and seems simpler and safer than adding DTPA.

Click to expand...

Thanks, distilled water is also the tip the Cookbook provides. You've never gone above 1:2 dilution? I wonder how the Cookbook authors got all the way to 1:5 or 1:10.

In the old Xtol datasheet 1+5 is recommended for Kodak Technical Pan Film. You may give it a try with other document films like Agfa Copex Rapid.

I use 1+3 for the development of Adox HR-50 with very good results (16 Min.). I use unfiltered tap water. The contrast becomes softer with such high dilutions.

FWIW, and use with caution, a link to the 1998 XTOL datasheet with 1+2 and 1+3 (shown as 1:2 and 1:3) times:
https://125px.com/docs/techpubs/kodak/j109-1998_04_b.pdf

ame01999 said:

Do you mean the results might be inconsistent, or that one day you might just get ruined negatives?

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I'd be concerned about consistency especially with longer development times, and I'd be wary of keeping around the mixed developer for any extended period of time (>30 minutes) at dilutions of 1+2 and weaker. In the pdf @MattKing links to above, Kodak is quite emphatic about the one-shot nature of these higher dilutions. I think there's good reason for this.

koraks said:

I'd be concerned about consistency especially with longer development times, and I'd be wary of keeping around the mixed developer for any extended period of time (>30 minutes) at dilutions of 1+2 and weaker. In the pdf @MattKing links to above, Kodak is quite emphatic about the one-shot nature of these higher dilutions. I think there's good reason for this.

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Thank you, very helpful. I still wish I could understand the Cookbook authors' paper test, though.

ame01999 said:

Thank you, very helpful. I still wish I could understand the Cookbook authors' paper test, though.

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It is a test for what is colloquially referred to as "sudden death". And paper was used because it is cheaper and easier than film.