both-dichromate and permanganate in acidic sol are very strong
oxidisers and will damage color dyes

#I'm wondering whether anyone knows if B&W bleach such as R-9
#dichromate/sulfuric acid bleach or alternately permanganate/sulfuric
#acid bleach used in conjunction with a conventional sodium sulphite
#clearing bath has any effect on color emulsion?
#
#I have some sound color motion pic. film where the silver soundtrack
#coating was applied on the wrong side thus there is a dark silver
#stripe down the right side of the picture and no silver in the
#soundtrack.  Fortunately the new red laser type soundheads will play
#the soundtrack properly even without the silver (needed for
traditional
#white exciter lamp play).
#
#So my question is: Can I remove the improperly applied silver stripe
in
#B&W bleach without negatively affecting the color emulsion?
#
#Ed

 In normal color film processing a silver image is produced
along with the dye. This image is removed after development
(or redevelopment in reversal work) by treating the film
with a bleach and then fixing. The bleach is such that it
does not affect the dye image. Reprocessing it in the bleach
and fixer stages should remove the silver and leave the dye.
 Silver sound tracks are produced by applying developer to
the sound track area after the bleach step but before the
fixer step. The developer is applied by a roller applicator
in the form of a rather viscous liquid that does not migrate
from the sound track area. The result is a silver image
there but not in the image area. What must have happened was
that the film was threaded backward so that the applicator
was on the wrong side, or, rather, the sound track was on
the wrong side. If this was done recently I would think the
lab would be obligated to do the job over correctly. I
wonder how they managed this very serious mistake.