>From experience as a research physicist for eleven years, be very
careful when using ANY of the statistical approaches. The assumptions
and boundary conditions are critical. I say this for the benefit of
anyone wishing to experiment with any new process.
The best method is as Judy suggests. Investigate one parameter at a
time. The multitude of variations can be reduced by making some careful
assumptions to eliminate variables. For example, include all the
ingredients necessary to make a gum print. It's nonsense to leave
something out.
I wasted a couple months with Anderson's test back in 1991. I was
investigating gum as a way to add color to a platinum print. The result
was some despair over the Gum process. It would have been nice to see
Judy's method back then. Maybe some "rainy day" I'll re-attempt some
Gum by way of Judy's techniques.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/