Re: Modifying bleaches

Charlie, Ferricyanide decomposes and give off cyanide in presence of
acid or strong light. I would not mix any acid to ferricyanide if you
are not very familiar with it. Cyanide gas is said to have practically
no odor and you may not notice its occurrence and accumulation in your
darkroom until you get poisoned. A gas like hydrogen sulfide is
probably just as toxic but at least you can strongly smell it at much
smaller concentration than the point where you get poisoning, so I
feel much easier.

There are lots of formulae in popular darkroom literature that are not
currently used. Some of them were dropped because they don't have any
advantage. Some were outdated because they don't work with modern
materials. Some were abandoned maybe because of other
reasons. Whatever it is, a lot of darkroom formulary compiled on paper
or on web are cut and paste work from old stuff without tracing
whether/why each particular formula is obsolete, and I feel that not
many of those darkroom formulary compilers test on their own to verify
the advertised claims to go with the formula. Then some reprinted
formulae have somehow important instructions, remarks, safety
precautions, etc. left out. Richard can give you lots of examples like
those.

--
Ryuji Suzuki
"People seldom do what they believe in.  They do what is convenient,
then repent." (Bob Dylan, Brownsville Girl, 1986)