Re: Scanning pigment stain

Good morning all! (long post, bewarrrrreeeee)
     While we're at stain again, I thought I might jump into the fray with
my experience this week, although I have no intentions of arguing pro or con
the Anderson pigment stain test--I've never done it.
     I first want to say a thanks to both of you, Katharine and Judy, the
"gum geniuses" of the list as I refer to you. Even when you disagree, I
learn. And where else do we find a forum nowadays where gum printers share
experiences??
     I have always argued pro-the old books; sometimes that is criticized
here, but IMHO to see how gum was practiced when people were actually MAKING
gum prints, and lots of them, has been invaluable. I have tried to collect
every piece of writing on gum from its inception. I'm close and am starting
on the German contribution.
     The stain test, with and without dichromate, with and without exposure,
was in most books, since gum's inception, probably due to practice and also
to Demachy's lengthy enough mention of it in his book. But as you point
out, Judy, it wasn't *as* scientifically complicated. The first mention of
the complex scientific test was Mr. C Wille in 1908. Then Anderson in 1917
did make it a complex process, but it was not original to him. Blame Wille.
     Why he chose sodium over the other forms of dichromates is a mystery
(he says speed). Mixed as he did to a solubility of 100%, it is a thick,
brilliant orange syrup, that masks the color of the pigment. And then to
use it in a 11:6 proportion...Yes, no wonder he had problems. However, if
you all remember, in testing this last summer I did not find it to be so
fast.
     This week I had a hilarious (not really) lesson in staining I thought
I'd share. Personally, there may be a relationship between amount of pigment
in the mix and staining, but I don't let staining be the controller of how
much pigment I use, does that make sense? I use a HUGE amount of pigment in
my mix: 2 tsp of thalo blue, for instance, a tube of it having been mixed
into 50 ml of gum, plus 2 tsp gum plus 3 tsp water plus 1 tsp saturated am
di. I would not need this to be any more saturated, pigment-wise (as an
aside, I never have flaking occur due to increased pigment, as some say
happens. Flaking is directly related only to too thick a coat, IMP).
     I went back to sizing my paper specifically because I did not want to
ever worry about staining. Sized paper doesn't stain, IMP, even with these
huge loads.
     This week, using up a leftover batch of Rives BFK, my paper of choice
for many years that I am now switching to Fabriano Artistico, I sized with
gelatin hardened with 3 ml of glut **outside** (thanks, Katharine).
     I noticed the BFK soaked the layer of gelatin really fast, and the
paper surface still felt velvety as that paper does. I also know that BFK
is a printmaking paper with little internal sizing. I only brushed on one
coat, instead of two, just to test whether two was necessary (BTW, the 3 ml
worked fine with the gelatin as a hardener).
    I have been doing a bunch of gum prints, and I had the oddest stain
effect crop up. The paper does not stain with the sizing, except in the top
most tiny fibers of the paper that did not receive the sizing because it
soaked in too fast. Thus I have a wonderful speckle effect across some of my
prints that does NOT come out with any kind of soak. It is only in the
highlights where there was no hardened gum/pigment layer to protect the
paper, and only with the third coat of pigment. I was doing a light shining
thru a keyhole image, and the speckled thalo was in the very center of the
keyhole, where the paper was bare of hardened gum, and not even on the
perimeter of the lighted keyhole, where there was a modicum of hardened
yellow color.
     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?
         <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?)
     5 days left til reviews and 12 more gums to go.....this list is SUCH a
wonderful divergence from work....
Chris
Received on Fri Apr 23 06:58:11 2004