Re: Liver of sulfur?

----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, November 01, 2003 10:37 AM
Subject: Re: Liver of sulfur?

> From: Richard Knoppow <dickburk@ix.netcom.com>
> Subject: Re: Liver of sulfur?
> Date: Sat, 01 Nov 2003 02:12:18 -0800
>
> > KBT also has some carbonate in it.
>
> If you read IPI report made to NEH on this matter, you'll
see a
> statement that Kodak engineers told IPI that KBT is
nothing but liver
> of sulfur and water. What MSDS lists as carbonate might be
a part of
> liver of sulfur or might be added later, or maybe other
possibility.
>
> > After toning rinse prints for a few seconds in running
> > water. Then immerse the print for about 1 minute in a
> > solution of sodium bisulfite bath consisting of:
> > Water 1.0 liter
> > Sodium bisulfite 30.0 grams
> > Then wash prints for at least 30 minutes.
>
> Where did this instruction come from? I don't think it's a
good idea.
> I recommend to immerse the toned print into 2% sodium
sulfite (not
> bisulfite or metabisulfite) without rinsing.
>
> --
> Ryuji Suzuki

    The source is the 1952 reprint of the 1947 edition of
_Processing and Formulas_ a booklet contained in the _Kodak
Reference Handbook_
    The Bisulfite rinse does not appear in earlier editions
of this booklet.
    I left out part, the instructions also recommend
hardening the print in a hardener made from the stock
hardener for Kodak F-5 fixer after the bisulfite rinse and
before washing. This hardening step is not included in the
earlier booklets. I suspect the reason Kodak asks for
Bisulfite rather than Sulfite is to neutralize the
alkalinity of the print before introducing it to the
hardening bath.
    Instructions for Agfa Viradon, which is also a
Polysulfide toner, suggest a "stop bath" of 10% Sodium
Sulfide before washing. I think some versions of the
instructions for KBT suggest the same thing.
    Polysulfide toners have the peculiar property of toning
faster as they become exhausted or diluted. So, the toner
carried over into the wash will continue to tone at an
accelerated rate until enough of it is washed out to stop
the process. Highly diluted Polysulfide toner will tone
highlights a peach color.
    For the most uniform toning of silver particals of
various sizes the toner stock should be concentrated. The
relationship is detailed in the IPI report to the National
Insitute for the Humanities (not sure if I am remembering
this right). However, Dr. Nishimura told me that T-8, which
is mixed at working concentration, would suffice.
    KBT contains both a substantial amount of sodium
carbonate, according to the MSDS about half the amount of
the Polysulfide, plus a small amount of Sodium Hydroxide.
    I think the alkali is necessary for the toner to work at
reasonable speed although it may have some other function.
The instructions for T-8 also suggest adding Sodium
Carbonate to the working solution to extend its life. When
it begins to get cloudy add 2.5 grams/liter of carbonate.
Approximate capacity is given as 150 8x10 prints per gallon.
    The IPI toner uses Borax as the alkali. IPI claims this
results in elimination of the Hydrogen sulfide odor until
the bath approaches exhaustion.
    In the interests of completeness and rigor I probably
should have copied out the entire instructions for T-8. I
have been critical in the past of the degradation of data as
it passes from hand to hand and sort of fell into this
myself.
    An example of this is in the instructions for Nelson's
Gold Toner as given in various Kodak publications. The
patent text, which is copies virtually word for word by
Kodak and Agfa/Ansco, specify a fixing step after toning,
this got left out of later versions of the Kodak
instructions. One of the editions of the _Processing and
Formulas_ booklets even states that prints toned in Nelson's
are not as permanent as those toned in other sepia toners.
Of course this is probably true if halides generated by the
toning process are not removed by re-fixing the print.
Prints toned in Nelson's should be very permanent.
Evidently, no one ever bothered to go back to the original
source, i.e., Nelson's patent.
   Re-fixing is also suggested in some other direct
sulfiding toners so someone at Kodak should have been awake
enough to catch the error.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com