From: Judy Seigel (jseigel@panix.com)
Date: 10/22/03-05:34:12 PM Z
On Wed, 22 Oct 2003, Richard Urmonas wrote:
> Someone may be more familiar with this formula. I would suspect
> the oxalic acid will modify the sensitivity curve a little. I do recall
> reading something about the acid being a preservative, but don't
> know how true that is. The addition of the acid will cause staining
> of the highlights. The dichromate will help to reduce this.
>
> Personally I think the simple formula is the best. It is also
> least harmful to the photographer and environment.
>
My tests showed that the formula with the oxalic made a more intense blue
for the first couple of days, tho double coating regular formula equalled
that. As the oxalic emulsion aged however, the whites became veiled --
the addition of dichromate simply stripped the high tones, that is,
cruelly shortened the scale.
(This is laid out in P-F #5.)
J.
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