Re: Sodium Bisulfite

From: Giovanni Di Mase ^lt;[email protected]>
Date: 10/14/04-02:22:35 PM Z
Message-id: <>

Thanks Katharine for letting us know.
Honestly, I took the word of Photoformulary as real and didn't have the time
to test it as you did.
What Alberto was mentioning to you is that there are two color stains, the
"dichromate stain" and the "chromium stain" and apparently the sodium
sulfite does not work on the last one.
Something else that Alberto mentioned to me is that he doesn't use and
clearing agent but leaves the print on just water the whole night and he
said it works better for clearing purposes.

----- Original Message -----
From: "Katharine Thayer" <>
To: <>
Sent: Wednesday, October 13, 2004 5:56 AM
Subject: Re: Sodium Bisulfite

> Katharine Thayer wrote:
> >
> > Giovanni Di Mase wrote:
> > >
> > > There is also sodium sulfite that works as sodium bisulfite according
> > > James book.
> > > But I was told that the sulfite does not create the solution acid and
> > > therefore the cromium component becomes insoluble cromium.
> > > What does this mean in terms of stains I don't know.
> > > Can anybody help?
> >
> > Giovanni,
> > I'd say, given the contradictory information you've been given, that the
> > best way to find out how sulfite compares to the others is to try it
> > yourself, side by side with sodium bisulfite or potassium metabisulfite,
> > and see what happens.
> Hi Giovanni,
> Just out of curiosity I did this comparison myself. I was going to show
> the results, but my scanner is scanning too red and in trying to fix it
> I'm not getting the results the right color and tone to accurately
> reflect the originals, especially to show a very very faint blue-grey
> tone accurately. Since I don't have any more time to spend on it, I'll
> just have to describe the experiment and results:
> I deliberately made a dichromate stain by coating paper (Fabriano Uno)
> with unpigmented dichromated gum, setting it in the sun for five
> minutes, then developing and drying it. The stain was tan-brown, the
> usual dichromate stain color. I cut the paper in half and put half in 5%
> potassium metabisulfite and half in 5% sodium sulfite. The half in
> potassium metabisulfite cleared in 5 minutes. The half in sodium sulfite
> also cleared completely, but took longer. After an hour, the tan-brown
> was completely cleared, but there was still a grey tone that I didn't
> like, so I left it overnight. This morning it was pristine white in the
> bath. Both of the cleared stains looked paper- white when wet, but on
> drying took on a slight bluish grey tone, very faint. The two halves of
> the cleared stain look so exactly the same color and tone that they look
> as if the paper had been cut after clearing rather than before; there is
> simply no discernable difference between the two halves of the stain.
> So I guess my answer to Giovanni's question is yes, sulfite works the
> same, but takes a bit longer. I'm wondering if it could be speeded up by
> increasing the concentration, but I don't have time to test that today.
Received on Thu Oct 14 15:19:23 2004

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