From: Christina Z. Anderson (zphoto@montana.net)
Date: 03/21/03-08:49:15 AM Z
> different from mine -- are you doing those tests on Rives BFK??
I'm mostly using BFK unsized and some others (fabriano, aquarelle) just to
test whether the "you don't need size" theory is actually workable. I have
been able to get clean whites one to two coats so far just fine, relying on
the sizing added to BFK, and that with pigment at a 6g to 12 ml ratio. With
the stronger staining colors, this is more difficult, so I would dilute that
amount with extra tsps plain arabic.
So I got out my scale and measured grams to teaspoons to help those
"gram impaired students" and found that even tho pigments vary across a
range of about 9 grams per 14 ml tube (a pretty big dif, but can be
predicted with the heavier metal ones weighing more) I am using about a
scant teaspoon of pigment to 3 tsp of gum for my initial color, mixing that
one to one with am di. That is a HUGE amount of pigment compared to what I
used to do, and if anything is to stain, that should, on unsized paper.
BTW, I was wrong AGAIN (two wrongs make a right actually, in this case)
when I said "whoops, permanent orange". There *is* a permanent red that is
very staining and it is pigment PR170 F3RK-70, or naphthol AS carbamide.
My info comes from the Daniel Smith catalog. I check their staining
chart for their D. Smith pigments and they have only a number of pigments in
the "4" category that is strongly staining. Then I check in Page's book and
see if she agrees. Then I go ahead and mix it full strength 6g/12ml and see
if it stains on unsized paper. I would think that would be a surefire test
to determine pigment stain :) See, my very illogical logic is you can
easily dilute a mixture.
So I tested this mix as is, against one mixed with 1 of this to 1 more
tsp gum, and then 1 of this with 2 more tsp gum (equal sensitizer to the
final mix) in strips side by side on an 8x10. That way I can determine
stain and depth of color and flaking and all. I expose 4 of those 8x10's to
6/12/24/48 minutes of UV time. It's as close as I can get to giving me a
clear picture of how a color acts. I bought one of those Itoya 48pp/96 side
portfolios for under $10 and that'll hold a great visual of all tests,
btw--wonderful tool to use. Tests all in one place, neatly, a real
'page-turner', so they never get lost.
As for the powdered pigment on top, I find the black I used (carbon) is
so oily that it is a messy way of doing the job, even tho it worked
(gritty) but I am not really inspired to test it again immediately. When I
do, I'll report back.
Chris
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