On Fri, 23 Apr 2004, Christina Z. Anderson wrote:
> Which leads me back to my personal "cause of choice" of staining, that
> was back in the old books from 1898: if the pigment is allowed to soak into
> the paper fibers, it will not leave. Some papers allow this more easily.
> The old books say, "Some papers are not suitable". Some papers have nice,
> stable, internal sizing. Some don't. Has the choice of paper ever been
> considered as why results differ in some of these tests? Have you, Judy
> and Katharine, compared paper "apples" to paper "apples" or are we talking
> apples to oranges?
Chris, I did many many tests when I first took up gum seriously and what I
found was that the rule is no rule. That is, some pigments stain with
some gums on some papers, but not with other gums on the same paper or
maybe other papers. Which is why, I believe, there is so much
disagreement about this medium... People don't realize that changing ONE
variable (paper, dichromate, pigment, gum, size) could change speed,
staining, grain, etc.
> <Judy said> And speaking of science, I think it was Karl Popper who
> said, all you need
> > to prove that not all swans are white is one black swan. I've seen
> flocks
> > & flocks of black swans...
> One black swan may prove that all swans are not white, but it doesn't
> prove that there are no white swans--that's the source of argument, IMHO.
> (Maybe all white swans are stained?)
I don't follow that. I meant that the *findings* of the GPR test are the
white swans. All you need is one contradictory finding to prove the test
is not valid.
J.
Received on Tue May 4 21:10:11 2004
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