From: Richard Urmonas (rurmonas@tpg.com.au)
Date: 10/21/03-01:49:47 PM Z
On Tue, 21 Oct 2003 11:05 pm, you wrote:
> I see that unblinkingeye site (very nice site of Ed Buffaloe - thank you
> very much) refers to Dick Sullivan's Cyanotype formula. The main
> difference is the addition of oxalic acid to both parts A and B plus the
> addition of ammonium dichromate to part B.
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.
Richard
--- Richard Urmonas
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