[QUOTES=Paul Verizzo;594533]
"A teaspoon of bicarb for Bath B? Bicarb????
Do you mean sodium carbonate? It's cheap stuff
and the pH follows concentration pretty well until
about 5 grm/liter, pH 10.5."
Carbonate makes for a very active developer.
It builds contrast fast. Bicarbonate is the one
to use. Harry wishes "to control contrast". A&H
backing soda will do well. The lower ph is
high enough to keep metol active while
delivering finer grain.
"Why would you go back and forth between the baths
without a good water rinse? Not saying that repeat
bathing may not be interesting, but if you drain Bath
B out and then fill with A, that A is contaminated.
The pH will start rising and then development will
be taking place in Bath A from then on."
One-shot chemistry. Any sulfited or higher ph
developer will not have to any practical extent
a lowering of ph.
Any off the shelf or Home Brew developer will do
as long as it is used very dilute. Solution volume
must be great enough to hold the necessary
chemistry at the high dilution; ie Rodinal
at 1:200 or D-76 at 1:7, 500ml.
Two tanks a reel lift and total darkness. Dan