From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 11/06/00-01:36:12 PM Z
"J. Wayde Allen" wrote:
> ... The pdlab site is
> commercial <http://www.pdlab.com/welcome.htm>, but I thought they had a
> pretty straight forward and simple description of the problem. Did you
> read it? What part of the description was wrong?...
For a commertial site I still find it strange that no identification is
given as to who these so called "product developers" are.
Yes I read it.
In general and incomplete simplistic terms it is not wrong. But then it
is the incomplete simplicity that can be misinformative. No where are
boundary conditions discussed (except hinted at as a "ranges in the
variables"). Assessing boundary conditions is as important as selection
of the variables. Errors are oversimplified and no discussion is given
to pitfalls of error accumulation, round-off errors, or limitations due
to measuring devices. All seem to be invisibly simplified into the
"bias error". And why not discriminate between linear and non-linear
variables, or isolated and interdependent variables. There are times
when changing one thing at a time will work, there are times when it
won't. There are times when statistical analysis can provide insight,
there are times when it is gibberish within a multitude of noise.
And what about the model, there has to be a statistical model. Part of
the real problem comes when a statistical model is introduced. It seems
more often than not too many assumptions, exaggerations, or
political/financial decisions influence the results. As far as the art
of alt-photo is concerned, perhaps results are achieved quicker by
making prints through trial and error changing things based on
experience and intuition.
So yes, I feel that site (pdlab) incompletely oversimplified what is
necessary to perform an accurate statistical analysis. And, I question
if such an analysis is even the best route to solving most alt-photo
optimizations.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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