Smieglitz@aol.com
Date: 07/11/01-10:33:19 PM Z
In a message dated 07/11/2001 23:01:29, kgerling@ameritech.net wrote:
<<Speaking of blue, and of staining, occasionally (like 90% of the time!) I
have unsuccessful prints and (snip)... the black, yellow, and magenta
pigments slough
off. But there is almost always a blue remnant (snip)...I'm not sure if this
is an example of "staining" but it certainly doesn't happen with any other
color.>>
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
*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 before anyone asks, the answer is no, I didn't do the stain test
according to the method recommended by Paul L. Anderson way back in 1917 in
his text "Pictorial Photography: Its Principles and Practice" pp. 195-197,
and repeated in every text on gum printing since. I did the stain test with
the addition of saturated potassium dichromate solution (@1:1 with gum) to
the emulsion. 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 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..."
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.
"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.
"You can't argue with success."
"Seeing is believing."
"A picture is worth a thousand words."
"The truth is out there."
"I got a million of them."
Joe Smigiel
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