Sandy King (sanking@hubcap.clemson.edu)
Tue, 26 Jan 1999 22:18:26 -0400
Hi Liam,
I don't think the formula, which I got from the 1947 edition of Neblette,
is in error because I used it extensively several years ago to harmonize
separation negatives for three-color carbro printing. With this application
I was able to make some very fine adjustments in the density range of the
three negatives to get them in line with one another so I know the formula
works, or at least it did at the time with the particular parameters of my
work involving conventional negatives. Also, I note that The Darkroom
Cookbook of Steve Anchell lists three formulas (#113, #116 and #117) for
bleach/redevelop reducers/intensifiers that contain hydrochloric acid.
Still, the bottom line is that in either the bleach or in some other area
of our work we are getting different results in bleaching and redeveloping
reversal negatives. Therefore, I would appreciate a short summary of what
treatment the negative receives from the time redevelopment is complete
until the time you place it in the harmonizing bleach. Are you fixing the
negatives after reversal, and if so, in what kind of bath (hardening fixer
or one with hardener), how long do you wash the negatives, do you wash
again before bleaching, etc.).
Thanks for your suggestions.
Sandy King
Hi, A message from Steve Shapiro is possibly relevant to t bleach you're
using. Probably you've seen it, but if not Steve asks about an amidol
"redeveloper" in the Darkroom Cookbook. The Cookbook gives Kodak S-6
Stain Rmover as the bleach to use with this redeveloper, and this consists
of pot. permanganate, sulphuric and sod. chloride. Now, permanganate +
sulphuric is another bleach that can be used in the reversal process (but
which I found inferior to the dichromate version), and it also changes
silver to (soluble) silver sulphate. With the sod. chloride included, it
will bleach to silver chloride, and I'm therefore wondering if the bleach
you quoted should in fact use sulphuric rather than hydrochloric. I'm not
accusing you of anything, but maybe the source you got it from got it
wrong? Wouldn't be the first time. If you wanted to try the
permanganate reversal bleach, by the way, simply substitute 50g pot. perm.
for the 50g of pot. dich., and clear in 5% sod. or pot. metabisulphite.
Liam
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