I care about the misspelling...

David Nebenzahl a écrit :

There have been packaging problems (mainly 1 liter packs) in the past
where part A was caked due to air leaks.
5 liters packs were usually fine, although I had one, certainly
manipulated to often, that wasn't air-tight anymore and part A became
quickly caked.
Actual packaging is a plastic bag, probably better than the former
paper-plastic-aluminium sandwich but still not bullet-proof. The old
cans were definetely much better but their cost certainly to high.
Anyway, if Part A is not the usual powder, better not use the pack.

The so-called "sudden failures" are different from the packaging
problems as they come from "normal" packs. Xtol working fine one day,
doesn't the next, giving badly underdeveloped negs.

Probably part of these failures are just due to the photographer
himself, errors in a darkroom are not so uncommon.
But, there have been enough cases reported by people I trust to say
there must be a real problem somewhere.

One possible cause is given by Ryuji Suzuki on his website:
http://silvergrain.org/Photo-Tech/ascorbate-dev.html
Where he indicates iron, either contained in water or as impurities in
the dry chemicals, as being the cause of the sudden loss of activity.
For those interested, he also gives some solutions (salycilic acid) ...

Not being a chemist and with little time left, I will not try to
validate this but it could be interesting.

What *I* do to make Xtol last as much as possible is:
- dilute part A completely before part B in demineralized water. While
stirring, I try to avoid to insert air in the solution.
- fill 4 1-liter brown glass bottles (pharmacy type) up to the neck
- use the remaining to fill ~8 100ml glass bottles (same type) again up
to the neck. 100ml being the minimal quantity required for a 135-36, 120
or 8x10". As I use it 1+1 by rotation, that's just fine to cover the films.
- once I've finished the 100ml bottles, I re-fill them with the content
of a 1-liter bottle.
- bottles are stored in a cupboard in the dark at room temperature.

Well, mostly common-sense, that's about 8-10 years I use it this way
without problems.
Maybe, I'm just lucky, but until I expect a failure in *my* conditions,
I'll continue to use this great developer.

Claudio Bonavolta
http://www.bonavolta.ch

Well, how about this non-horror story?

When I first heard about all this Sudden Death Syndrome for Xtol developer,
I put aside a 1-pint glass bottle of stock solution mixed September 15, 2000
filled almost to the brim, and another one filled half way, with air in the
rest of the space.

Today I tried developing a clip of TMX 35mm in incandescent light in the
solution, pail yellow, of the 1/2 full bottle, and it did turn it gray, but
by no means black. So I rinsed things out, and tried again with the stuff
from the full bottle, then rinsed and dried it. It looked pretty black to
me. I then measured the gross density and it was over 3.5, so it looks as
though age alone is not the problem. I no longer recall if the stuff was
mixed from a 1 litre bag or a 5 litre bag, but I am very sure it was mixed
with 5-micron filtered tap water, not distilled.

I'm not a chemist, either, but I've read a good deal about this topic --
mostly Web pages, but a few articles in photo magazines. My impression is
that you've asked a question whose answer is far more complex than you
might think. The chemistry of film developers is much more complex and
much less well understood than you might imagine, particularly when you
factor in things like varying impurities in tap water in different areas.

That said, there doesn't seem to be a consensus on a single cause of the
XTOL sudden death syndrome, at least not among the general photographic
population of the Internet. (Perhaps Kodak knows something solid, but they
aren't talking about it.) There are lots of hypotheses and proposed
workarounds/fixes, including:

- Bad packaging causing oxidation before mixing, the solution being
 Kodak's change in packaging a while ago. Reports of XTOL failures have
 occurred well after this change, though, so at best it didn't fix
 everything.

- Easier oxidation of XTOL than of other developers, the solution being
 more careful attention to proper storage (tightly sealed and full glass
 bottles, no exceptions).

- Impurities in the mixing water (especially certain metals), the solution
 being mixing with distilled and de-ionized water.

- Greater amounts of dissolved oxygen in XTOL because of longer
 room-temperature mixing times, the solution being to heat the mixing
 water to 35C for quicker mixing. Because of the previous hypothesis,
 the water should be heated in a non-metallic container.

- High-dilution problems with some films (particularly T-Max 100), the
 solution being to use XTOL at no greater than 1+1 dilution, particularly
 with T-Max 100 (and perhaps other T-grain) films. This isn't really a
 cause of failures, but an observation that they seem to occur more
 frequently with some films and dilutions than with others.

- No real problem, the hypothesis being that people talk about XTOL
 failures, which brings people out of the woodwork to report more
 failures, which turns into a self-perpetuating cycle of talk about XTOL
 failures. The claim is that other developers fail as often but this
 cycle just hasn't started with them. Because the talk about XTOL
 failures is talk on forums like this one, there is, to the best of my
 knowledge, no solid publicly available data about the frequency of XTOL
 problems, which makes it impossible to confirm or disprove this
 hypothesis. Nonetheless, I'm skeptical of this hypothesis, but I report
 it for completeness.

There are probably other hypotheses/suggested fixes, but these are the
ones that come immediately to mind. Note that the frustrating thing is
that the failures are unexpected and, on the whole, rare. (Watch, though;
somebody is likely to reply that they've had multiple XTOL failures.
That's chance for you.) You may have gone through a dozen packets of XTOL
without problems and the thirteenth will fail at some point. This makes
taking the above precautions and doing "snip tests" important.

One more point: XTOL isn't the only developer that's reputed to fail
suddenly and unexpectedly. This seems to be common among ascorbic acid
developers. AFAIK, the only other commercial ascorbic acid developers are
Paterson FX-50 and Agfa Neutol Plus. (The former is a film developer; the
latter is a paper developer.) Quite a few mix-it-yourself ascorbic acid
developer formulas have been published, though, some with the goal of
improving storage characteristics. Some of the more prominent of these are
Ryuji Suzuki's DS-10 and DS-12 and Patrick Gainer's PC-Glycol and PC-TEA.
Given the unpredictability of XTOL failures, it's hard to evaluate these
formulas' ability to resist the problem; you'd probably need to mix up
thousands of liters of each developer to get statistically significant
results in any test, and then there'd be issues of water supply and other
variables that might affect one formula more than another.

Curiosity like this reminds me of why we have traffic jams.

Not completely understood. Michael Gudzinowicz probably had the
background necessary to study the phenomena however the variables are
extremeled broad in scope.

Nope. Not entirely. Very few commercial formulas are published today
diue to the amount of legal mechanations going on today.

This is not one specific reation but rather it is probable that there
are several similar reactions that can take place. The commonality if
metals in the water. In particular copper and/or iron make cause
significant oxidation of the ascorbate. One of my theories is that
this may also impact the Phenidone variant that Kodak uses in Xtol.
There is a very minute amount of Phenidone in each batch and if that
is compromised then halide oxidation (reduction) may be comprised
thereby significantly slowing the induction period of the image
development.

Give it a whirl. But don't be surprised if you don't find any visible
difference between it and D76.

==
        John - Photographer & Webmaster
     www.puresilver.org - www.xs750.net

I started using Xtol because I liked the results I saw from a photographer I
respected.  I know quite a few photographers who use Xtol frequently.  I
usually go through a 5L pack within a few months, myself.  I've used Xtol
that has been mixed up and stored for over a year.  I like the results I
get.

Try it.  See if you like the results.  If you don't, move on to something
else.  The only place I see the horror stories of sudden Xtol failure
repeated is here on Usenet.  I have no idea why that is.

Kodak did have problems with their earlier packaging.  I have thrown away a
single 5L pack because it didn't feel right to me.  The powders inside were
clumped, like it had gotten some moisture in it already.

If you're happy with the other developers you use, don't worry about trying
Xtol.  If you want to experiment, do so.  I guess what I'm saying is don't
let relatively few naysayers influence your decision.

Take a few precautions.  Don't let air contact the solution once you've
mixed it up.  I use 250 ml bottles and fill them to the very top.  I've
never had a problem.  I settled on 250 ml because I usually use a 1 L
developing tank.  This way, I can grab 1 bottle if I'm using Xtol 1:3 and 2
bottles if I'm going 1:1.

That said, don't start off with any roll that is important.  Same as when
you try any new process.  It may take you a few tries to figure out how to
use Xtol and get acceptable results.

That has been my experience but I haven't done the densitometry to
back it up. Someday I have to take the time for that. Also the
highlights do flatten out a little when you use the 1:3 dilution.

==
        John - Photographer & Webmaster
     www.puresilver.org - www.xs750.net

John <use_net@puresilver.org> writes:

I don't know -- my developers fail all the time: I go to pour some
out and find it has turned dark brown and smelly; this happens
many times per year.  For all I know, XTOL may fail much less often
than standard D-76/MX/TMax etc..

The problem with Xtol is you _don't know_ when it fails.

"Sudden Death" with Xtol is suddenly finding out it has
failed when you open the developing tank.

To my mind this is a far more serious problem than Xtol's
keeping properties.  What sort of bottle is needed and how
much air to allow and what water to mix it with aren't
really germane to the issue.

While I agree that a lot information posted in most usenet newsgroups I've
found that most of the people here are very knowledgeable<SP?>. The
reputations of a number of people that have had issues with xtol failure
is impeccable.