BLEACH
[Film Technology]
Rolls
of exposed film staples together and attached
to the end of the film already on the processing
machine. Film then travels over guide rollers
through numerous tanks for the pre-bath, backing removal, developer,
stop bath, bleach,
fixing and stabilizer,
interspersed with washes to avoid chemical
transferring from one bath to the next. See processing
and processing
machine. In the final stages the film may be chemically hardened, before
passing through drying cabinets and spooled into
each customer’s rolls. The bleach solution
contains bromide, together with an oxidizing agent
ferric cyanide or persulphate
whose function is to reconvert the developed silver back to silver bromide.
Persulphate is less damaging ecologically, but requires an additional
bleach acceleration in order to work effectively. In the bleaching process, ferric canide is reduced to ferrocyanide.
e-mail : pratheepvasudev@gmail.com
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