"Keith Tapscott."
wrote in message
...

Most B&W developers contain Hydroquinone with either Metol
or Phenidone
or a Phenidone derivative. Both Metol and Phenidone are
super-additive
with Hydroquinone, so why add both of them in the same
developer
formula?

Here is an example of a developer which contains all three
of those
constituents.
http://www.tetenal.com/sidaopener_uk...auk/100152.pdf




--
Keith Tapscott.


I've wondered the same thing. There are a number of
developer formulas that have more than two developing agents
in them, sometimes puzzeling combinations. My chemistry is
not good enough to know why.


--
--
Richard Knoppow
Los Angeles, CA, USA