From: Judy Seigel (jseigel@panix.com)
Date: 07/12/01-08:13:59 PM Z
On Thu, 12 Jul 2001 Smieglitz@aol.com wrote:
> If anyone would care to see visual results of a stain test I performed using
> Daniel Smith colors on sized 300# Lanaquarelle you can view it online by
> surfing to:
>
> http://members.aol.com/kallitype/staintest.jpg
What was the size? What was the gum?
> *In my experience*, the pthalo colors always stain to some degree, in
> agreement with the manufacturers' ratings and this test shows the results.
> (I also note what is an acceptable amount of stain can vary among different
> individuals.) *In my experience*, the heaviest staining pigments include
> Daniel Smith Pthalo Blue as well as the often recommended Winsor & Newton
> "Winsor Blue". The test jpeg shows various DS pthalo and quinacridone
> pigments at varying concentrations.
And in my experience, many of the combos with thalo blue had the least
staining. But then, EVERY TIME I've done a big batch test, I've found
nearly every combo is different. If you're using rabbit skin glue, for
instance, won't be same as mine on Knox. I've tested 4 different gelatins
and found each performed differently. And degree and method of hardening
also changes the deal. Also each gum arabic is a variable... So, though I
have found the thalo's definitely NOT staining with my combos, they
apparently are with yours.
Which was why I'm not convinced by a generic "stain test."
As for concentration... this is something I've tested a few times, tho
obviously not with all ingredients, but I found (as shown for instance in
P-F #2, page 46) that "twice the pigment or as much pigment as the
emulsion could hold without flaking and as strong a color as the paint
could make did NOT cause more staining. [Although] of course if you're
getting stain in the first place, you might well get twice as much with
twice as much pigment -- there's just more of it around to stain..."
That test was with ultramarine which stained heavily in one make, very
little in another.
> ... And yes, "your mileage may vary", especially if you choose to
> use stuff like BFK and Knox (often recommended as well in texts) which, *in
> my experience*, only increases the amount of stain remaining after processing
> compared to other available materials.
I've done tests of a bunch of variables on several papers and found that
the BFK & Knox stained the WORST in some tests and the LEAST in others.
It's the combo -- and frankly I've never found the key to it -- a RULE
that could be applied across the board. (And I DON'T think that's "out
there somewhere." Or so far not a clue.)
I'll add however that a couple of years ago I exchanged gum arabic with
someone from the list and found that his -- all other variables remaining
the same -- performed DIFFERENTLY, completely differently, from mine. I
use several different gums, for varying speeds, more than anything else...
but also have not found a general rule for how they'll perform in combo.
Each is sui generis. Often things will be the same with a different gum,
but just as often not.
He also said that his worked differently at his friend's across town --
even though he brought own lights and materials. We speculate that the
WATER is a big variable (developing water), which could well explain
various other anomalies (eg., why some get heavy dichromate staining,
others almost none).
> I note also that Mr. Anderson has some good advice on that very subject:
> "Inasmuch as the proportions of the coating mixture will vary with the
> pigment used, with the paper on which the print is to be made, and with the
> result desired, every worker must determine for himself what mixture he will
> use in a given case, and although numerous formulae could be given, to do so
> would occupy an excessive amount of space and would serve no useful
> purpose..."
One variable I found that he omitted is WHICH COAT -- that is, a combo may
behave VERY differently as first coat than as, for instance, third.
> There is a marked difference between the amount of staining with the pthalo
> pigment and the other quinacridone colors, as well as between various
> concentrations for each pigment evident on the test. The extreme lefthand
> edge of the Pthalo Blue area shows the difference between sized and unsized
> paper as well.
I would assume pthalo would stain heavily on unsized paper, but haven't
(as I can recall) tried it.
> "Experience is the best teacher" so I would encourage anyone interested in
> gum printing to run their own tests rather than relying on what has been
> written in the standard references. That way, you can decide for yourself
> which pigments work for you and your individual methods and materials.
Joe, Keith, I'd agree with all this and the following as well. I'd just
add, lest folks be intimidated: It's NOT as tricky & quixotic and queer as
this makes it sound. It's just that EVERY VARIABLE changes the combo. I
remember when someone wrote the list in perplexion why the second coat
he'd put on his print came out so differently, when he'd done everything
JUST the same. But the 2nd coat was a different color... And for all we
know, a different brand. (Not to mention that it was the second coat.)
> "You can't argue with success."
>
> "Seeing is believing."
>
> "A picture is worth a thousand words."
>
> "The truth is out there."
Maybe, maybe not...
cheers,
Judy
This archive was generated by hypermail 2b30 : 08/02/01-11:56:46 AM Z CST
