From: Katharine Thayer (kthayer@pacifier.com)
Date: 04/14/03-06:05:29 AM Z
Christina Z. Anderson wrote:
>
I think the original thread about stain was moreso that the old adage
> that too much pigment stains is not *always* true, not that too little
> *always* stains. In other words, with higher ratios of pigment to gum than
> I was using before (3g/50ml) the dreaded stain did not appear with some
> pigments even up to 6g/12 which is equivalent to 8 times what I used to
> use--this on SOME pigments.
I think it's a shame that Chris was instructed in school, as she told us
earlier, that 3g/50ml of gum was the right amount of pigment to use
regardless of the pigment. (--Another reason to stay away from schools!)
;^) But I think the issue should be with the idea that one size fits
all, instead of with the idea that too much pigment will stain. To me,
the important question isn't whether too much pigment will stain but
what pigments, and how much is too much of what pigment packaged by what
manufacturer? I don't think anyone here would say as a rule that more
than xg of any pigment in x ml gum would stain, since it's so variable.
I mix colors intuitively rather than by weight, so I can't say by grams,
but 3 grams in 50 ml sure doesn't seem like very much pigment to me, in
fact if it were really true that too little pigment causes staining, you
might be in trouble here.
But seriously, it makes a huge difference, as Dave Rose and I and others
argued in that earlier thread, which pigments and which brands of paint
you're talking about, how much pigment might result in staining. Too
much of one pigment might be ten or fifteen times what too much of
another pigment is, depending on the brand. Even for the same pigment,
wide disparity between manufacturers in how much pigment they put in a
tube of paint results in wide differences in how much of that paint
should be added to a given amount of gum to get the same density. So it
just doesn't make any sense (I'm sure I'm repeating myself, and maybe
talking to myself, who knows) to give a set amount of pigment to use in
a given amount of gum, as a general rule.
Katharine
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