Sil Horwitz (silh@iag.net)
Wed, 27 Jan 1999 12:19:05 -0500
At 08:38 AM 1999/01/27 -0500, you wrote:
>It sounds like the dye from the anti-halation layer to me, as Kerik also
>pointed out. Jobo recommends using fixer to remove the stain. I think whether
>you use a developer or fixer, it is the sulfide that clear the stains. Some
>recommend using hypo clearing agent which is sulfide+bisulfide. I have tried
>it and it works too.
Watch your chemical terms. "Sulfide" is a killer in photography, used only
in brown toning. Anywhere else it will fog any silver it can get to. (The
"fading" of some silver prints to sepia tones is due to sulfides in the
atmosphere.)
What you mean is "sulfite" the grand universal everything in photography, a
totally different substance. HCA is primarily sodium sulfite, with sodium
bisulfite as a buffering agent, and EDTA to minimize mineral deposits.
Surprising what difference one little character can make!
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/
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