[Leica] Xtol question

[mark at rabinergroup.com (Mark Rabiner)]

> Very interesting detail from Marty.
> But I have to say, given the XTOL reputation of rapid onset and 
> catastrophic
> failure to soup, don't even mess with the current
> batch. About the same cost for a gallon or so, as a roll or two of film, I
> think. Maybe you like to live on the edge;-) Not really
> too awkward to mix, is it?
> Kodak's official storage figure for partially filled, tightly closed 
> container
> "at least two months", "approximately 1 year" in
> full, tightly closed container.
> 
> Just my two cents
> Cheers
> Hoppy
> 
> 
> -----Original Message-----
> Subject: Re: [Leica] xtol question
> 
> Very interesting -- I'll give it a try.  Anything to
> avoid mixing up another 5 liter batch of nasty
> powdered chemicals.  Since I don't have a
> densitometer, the Kodak test strips -- whatever they
> are -- are not an option.  Tip of the hat to John
> Black as well.
> 
> Of course, if the test yields a false positive and I
> ruin a critical batch of film, it's on you guys.  ;-)
> 
> Peter.
> SF, CA
> 
> P.S.  OTOH, I never seem to have any critical batches
> of film -- so I can afford to experiment.
> 
> --- Marty Deveney <freakscene@weirdness.com> wrote:
> 
>> Peter,
>> 
>> It is possible to test if your Xtol is still
>> working.? 
>> 
>> The simplest way is to take a strip of film and in
>> ordinary room light place a drop of Xtol on the
>> emulsion side of the?film.? After 10 seconds, put
>> another one a little further along.? After 20s more,
>> put another one on.? Put another one on at 1
>> minute.? Rinse, fix and wash.? Without a
>> densitometer it's hard to quantify and therefore
>> it's hard to tell if it?has partly oxidised, but you
>> should have spots of increasing density.? Xtol also
>> tends to die quickly, so partial loss of efficacy is
>> pretty unlikely.? LuGer John Black put me on to this
>> and should be acknowledged as the source of this
>> simple, elegant and effective method.
>> 
>> The other way to do this is to buy some Kodak test
>> strips, develop one in it and see how it looks and
>> check with a densitometer.? That would be the most
>> precise way to do it.
>> 
>> Marty
>> 
>

Lots of people add an ascorbic acid tab or measurement to their d76.
That would be a Metol or Elon coupled with ascorbic acid instead of a
Phenidone couplet as in Xtol.
But I'm more fond of the effects of Metol or Elon than Phenidone anyway.
When I get back into souping if I don't just mix up each batch from scratch
by hand as I go along I'll be doing this.

I think the magic of Xtol is what ascorbic acid does when working with
Phenidone. That instead of Hydroquinone.
But I think coupled with Metol it would be better.
And mixing up from scratch or just adding a vitamin C tab to a favored MQ or
PQ developer would take way Xtol Paranoia.

This is the MSDS for Xtol was posted by Richard Knoppow on the RUG a year or
so ago:


Dry Formulation

Part A
Sodium Sulfite 10.0 grams
EDTA penta sodium salt 1.0 gram
Sodium metaborate (8 mol) 8.0 grams
4-Hydroxymethyl-4 methyl-1-
phenyul-3-purazolidone
(Kodak Dimezone) 0.2 gram

Part B
Sodium Sulfite 75.0 grams
Sodium metabisulfite 3.5 grams
Sodium Isoastorbate 12.0 grams

Ingredients in Part A to be dissolved in 850.0 ml of water at room
temperature. 

When dissolved dissolve Part B in add water up to 1.0 liter pH of the
solution after dissolving Part A should be 10.19 +/- 0.05 pH of complete
solution after adding Part B and water should
be 8.20 +/- 0.05 
The metaborate (Kodalk) and metabisulfite should be a pretty good buffer.
Note the very small amount of Dimezone.
The EDTA is evidently important.
Dimezone is a Kodak trade mark for a Phenidone derivative which is supposed
to be more stable than Phenidone.
The patent also gives a liquid concentrate version of the formula. For those
who want to experiment with this I suggest downloading the patents. They are
USP 5,756,271 and5,853,964 Any US patent every issued can be gotten free of
charge from the U.S.Patent and Trade Mark Office web site at
http://www.uspto.gov Older patents are available as Type-4 FAX tiff images.



End of quote


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Mark William Rabiner
Harlem, NY

rabinergroup.com