Re: Scanning pigment stain (FLOGGING A DEAD HORSE)

From: Sandy King ^lt;[email protected]>
Date: 04/23/04-08:01:06 AM Z
Message-id: <a0602042ebcaecfdaf531@[]>


Not only is this horse dead but the vultures have already picked
through every decent morsel on the carcass.

I say do what Dave suggests. Go try the (in)famous gum test yourself
if the subject motivates you. If the test reveals anything of
interest use it to make some prints. And be sure to send the results
to JS and KT.


>Let's put a sub-heading on this thread.... Flogging a dead horse.
>Like Katharine, I've fully explored the "Gum pigment ratio test" or "dot
>test" with similar results. DESPITE ITS LIMITATIONS, I found it a helpful
>tool for determining preliminary pigment to gum ratios. I did this test
>many, many years ago, long before Judy Seigel was around to tell me it is
>'wrong'. My actual test results will always speak louder to me than Judy's
>flawed arguments driven by her personal agenda to disprove/discredit prior
>authors on the subject.
>This subject has provoked tiresome and pointless arguments for a long time,
>as evidenced by Judy's admission that she's addressed the issue "298 times".
>For those gum printers who've never done the dot test, why not try it (with
>an open mind) and reach your own conclusions? Use two very different
>pigments such as phthalo blue and raw umber. Just follow the directions
>detailed by Crawford or Scopick and see what happens.
>Best regards from Big Wonderful Wyoming,
>Dave Rose
>----- Original Message -----
>From: "Katharine Thayer" <>
>To: <>
>Sent: Wednesday, April 21, 2004 5:50 AM
>Subject: Re: Scanning pigment stain
>> Sorry folks, I've been unsubscribed and not reading the list for several
>> weeks so I could get some other things done (sometimes when I get too
>> interested in what's going on here I just have to pull the plug on
>> myself) and have just now read, from the archives, back to where I left
>> off. Mostly I'm content to just read and not feel I need to contribute
>> anything so long after the discussion, but this one post deserves some
>> comment.
>> (BTW, the last time I posted a reply quoting a post from the archives,
>> surrounding the quoted material with quotation marks and embedding my
>> comments, I found that my comments got lost in the quoted material. So
>> this time, I will separate my comments from the quoted material with
>> lines):
>> Judy Seigel wrote, on April 3, 2004:
>> On Fri, 2 Apr 2004, Katharine Thayer wrote:
>> > Judy Seigel wrote: (March 24, 2004)
>> > >
>> > In fact, I've just done some tests which I am about
>> > > to scan proving that his Great Gum Pigment Ratio Test of universal
>> > > is as wrong as I said it was 298 times. .
>> >
>> > So did you scan these data and are they somewhere where we can see them?
>> JS: I scanned 6 of about 50 tests and will show them in Post-Factory #9,
>> to be
>> finished any second now. Actually I have trouble believing that I'm the
>> only one who has done this sort of test -- or maybe I'm the only one
>> rash/cruel enough to mention it. I don't think that the scans by
>> themselves are going to convince anyone who doesn't want to be
>> convinced... among other reasons being that scans are so easy to fake.
>> I'd
>> suggest rather doing one or two of the tests for yourself.
>> ____________________________________________________________________
>> KT: Two of the three tests described below don't address the usefulness
>> of the Anderson test, but at any rate I have done both of the kinds of
>> tests described below, and have gotten different results than Judy
>> reports, and have reported them here before.
>> Besides running a rough version of the "Anderson test" early in my gum
>> printing career, which ended the problem of pigment staining for me
>> forever, I also ran a controlled test two or three years ago with test
>> strips, which to the best of my recollection I posted to the Bostick and
> > Sullivan website and posted the URL here so everyone could see the
>> results. Using the same progressively increasing pigment/gum ratios in
> > two conditions: (1) no dichromate and no exposure, as in the Anderson
>> test, and (2) dichromate and exposure, as in Judy's third test, I found
>> that staining appeared at exactly the same pigment/gum ratio in both
>> conditions. In other words, my results supported Anderson, Crawford,
>> Scopick, and the rest who have reported that they have used this test
>> and found that it works.
>> I've said this, not 298 times, since I don't have the time or energy to
>> respond every time the "Anderson test" is trashed here, but let's say
>> ten or twelve times: my experience and findings do support Anderson,
>> Crawford and Scopick. But my experience and findings often seem to carry
>> little weight here, which is discouraging at the least.
>> The standard caveat holds as always: when I say my results differ, I
>> don't mean to say I think Judy is wrong, any more than I think Judy's
>> differing tests mean that the rest of us are wrong. I only mean our
>> results differ.
>> _____________________________________________________________________
>> JS: I wrote an article of approximately 1,978 words on the topic,
>> tracing the
>> discourse & practice through the canon from 1901 to 1939, and so forth,
>> mostly in their own words.
>> _____________________________________________________________________
>> KT: It's too bad you didn't go back three more years, to Demachy, (who I
>> think we can all agree was a master of gum printing) who said that the
>> ratio of pigment to gum is what causes staining, which is what my own
>> experience has taught me. I think it was Christina who first mentioned
>> Demachy's priority to Anderson on this truth, but I have a copy of this
>> 1898 article (no, I don't read historical stuff as a rule, but I came
>> home from the library with this article quite inadvertently one day and
>> have confirmed with my own eyes ;-0 that Demachy understood this
>> principle even before Anderson did.)
>> This reminds me somehow of a small bone I have to pick with Bob Schramm,
>> who said, the last time Judy and I went around on this issue, that he
>> had seen Judy's prints and so he believed Judy over anything I had to
>> say. This is a very odd statement for a self-described scientist to
>> make, considering that at the time it's very unlikely that he had seen
>> any of my work. In fact, that was the trigger that finally got me to
>> take the time to put together a website: I decided it was time for
>> people here to see some of my work so there would be no more of that
>> kind of nonsense. So those of you who have appreciated my website have
>> ultimately to thank Bob Schramm for it.
>> _______________________________________________________________________
>> JS: Here are the last 2 paragraphs (this being brought up to Pine on the
>> clipboard has lost all apostrophes & quote marks, also a few dashes, but
>> I
>> think is clear enough....)
>> <snip>
>> my own mini-salute to science, I demonstrate that (1) pigment
>> stain
>> in a gum print changes with the dichromate concentration,
>> ____________________________________________________________________
>> KT: This is a different issue than the question of the usefulness of the
>> "Anderson test", but at any rate, I have not found this to be true in my
>> own practice. Since I print with saturated ammonium dichromate with
>> saturated colors and no stain, this conclusion is inexplicable to me and
>> at the very least cannot be taken to be generally applicable. I'll have
>> more to say about these results farther down where the actual tests are
>> described.
>> ______________________________________________________________________
>> JS: and (2) pigment
>> stain may be less with the dichromate than without it.
>> ______________________________________________________________________
>> KT: Again, I find this not to be true in my own practice. I find it
>> interesting that Judy reports less pigment staining with dichromate and
>> exposure than without; others (for example Joe, I think) have reported
> > more pigment staining with dichromate and exposure, and I have found, as
>> has Scopick, no appreciable difference with dichromate and exposure. Why
> > we get differing results is puzzling, but to simply assume that those
>> who get differing results from you are WRONG, or even that they couldn't
>> possibly have run the test they claim to have run, is not a
>> scientifically sound position to take, and insulting to your
>> colleagues.
>> _______________________________________________________________________
>> JS: In figures A & B
>> above, both pairs have the same ratio of liquid, pigment, and gum, but
>> the
>> right-hand strip of each pair has a greater concentration of dichromate.
>> _______________________________________________________________________
>> KT: These two tests have no bearing on the question at hand, whether the
>> ratio of pigment/gum affects staining, since the pigment/gum ratio is
>> held constant. They address a different question, whether pigment
>> staining is related to dichromate concentration. As I've already said,
>> and will say again, my experience and findings show no relation between
>> dichromate concentration and pigment staining; in other words my
>> findings directly contradict these findings.
>> ______________________________________________________________________
>> JS: Figure C, which by itself disproves Anderson (and took less than 10
>> minutes, not counting the soak), shows that the way Anderson-style
>> pigment-in-gum-only clears (or doesnt clear) in water does not
>> necessarily
>> parallel the way pigment exposed in sensitizer clears in water. Since
>> the
>> tests are no more difficult to make with the dichromate and exposure
>> than
>> without, I have no theory about why Anderson omitted it.
>> _____________________________________________________________________
>> KT: This is the one test of the three which does address the question of
>> the Anderson test, but it doesn't "disprove" anything; it simply fails
>> to confirm others' findings. The tests I did, which were more extensive
>> than the test described above (if I could access that jpeg, I would
>> re-post it now to illustrate the point, but unfortunately I stored it on
>> a floppy and my floppy drive is toast) contradict the findings described
>> here; in other words what I found was that how the pigment-in-gum-only
>> clears in water parallels exactly how the pigment in gum exposed in
>> sensitizer clears in water.
>> _____________________________________________________________________
>> JS: In other words, Anderson had it exactly backwards. The control is
>> dichromate, not pigment-to-gum.
>> ______________________________________________________________________
>> KT: And my findings and my experience in practice say that Anderson (and
>> Demachy) had it exactly right: the control is pigment-to-gum. Since
>> there doesn't seem to be any way to resolve this, all we can do is agree
>> to disagree.
>> _____________________________________________________________________
>> JS: There are of course many other potential
>> variables, but these are constant. The moral of the story is that no
>> matter how logical a system seems to the engineering mind, nature has a
>> logic of its own. Which is probably why real scientists test their
>> theories. They make mistakes, but rarely such foolish ones.
>> _____________________________________________________________________
>> KT: What you seem to be suggesting here is that anyone who actually
>> tested this would come up with the same result you came up with, which
>> is simply not accurate, as I and Scopick and others have demonstrated
>> with our own observations and findings.
>> ______________________________________________________________________
>> JS: There follow 7 footnotes & a caption for the scans which details the
>> procedure. This cannot be done without a 21-step or comparable
>> sensitivity guide. Not that wonderful prints and a good understanding
>> can't be gained by using what I'd call "picture negatives," but however
>> lovely the image, the ordered and numbered density in a specific range
> > is
>> needed to establish this kind of info...
>> _____________________________________________________________________
>> KT: My tests, described above, which were available for all to see,
> > were done with 21-steps.
>> ______________________________________________________________________
>> JS: Here are the details, again with italics, quotes, etc. missing, but
>> the idea should come through...
>> Figure A: Rowney Jet Black gouache, a new tube which (unlike the old
>> one)
>> tends to pigment stain; paper is back of a print on Uno. Each strip has
>> 4
>> drops of paint (slightly diluted with water to measure), 10 drops
>> lithographers gum,
>> ______________________________________________________________________
>> KT: I really wonder if this isn't the key right here. I've come to
>> believe from my own observations that the "lithographers gum" (by which
>> I mean the black, heavy, sediment-filled, viscous stuff like the Daniel
>> Smith standard gum or the gum that Photographers' Formulary started
>> carrying a year or two ago) is not the same substance as what I mean by
>> "gum arabic." Anyone interested in my thoughts and observations on the
>> difference can read about it on my website:
>> Since Demachy, Scopick, and I (I can't speak for the other guys) have
>> used the one kind of gum, and Judy uses the other, perhaps this in
>> itself could account for the difference in observations.
>> ______________________________________________________________________
>> JS (cont) 10 drops sensitizer (6% am di at left, exposed 5 min.,
>> 13% at right; exposed 4 min.), still-developed one hour. Six steps are
>> visible in left strip, but right strip, with twice the dichromate, didnt
>> clear at all.
>> _______________________________________________________________________
>> KT: I wonder how you settled on 4 vs 5 minutes for the times. My tests
>> on the relation between dichromate concentration and speed, shown here
>> several months ago, showed a linear, close to diagonal relationship for
>> contone film, which I assume the Stouffer test strips are. If that
>> observed relationship reflects the actual relationship, then 2.5 or 3
>> minutes would seem more appropriate for the 13% dichromate, in which
>> case it seems distinctly possible to me that what looks like "pigment
>> stain" may be simple overexposure.
>> _____________________________________________________________________
>> <snip> [KT: since figure B is the same as figure A with a different
>> pigment, the same comments apply]
>> JS:
>> Figure C: Strip at left, the same Jet Black gouache on sized Fabriano,
>> pigment, gum, and sensitizer, exposed 5 min., yields 5-1/2 visible steps
>> and *clear whites.* The tone at right is the same proportion of color
>> and
>> gum (4 drops to 10 drops) on the same paper, but a la Anderson, no
>> dichromate, no exposure; soaked one hour. (Need I say more?)
>> PS: The "tone at right" I speak of is about a 20% gray. The strip with
>> the
>> dichromate cleared perfectly.
>> ______________________________________________________________________
>> KT: This is interesting, but hardly devastating; as I've already said
>> more than once, my findings differ on this point, and as you rightly
>> predicted, I can hardly find this one data point convincing against all
>> my experience and observation and my own more extensive tests, which did
>> address the question of whether the Anderson test is relevant to gum
>> printing practice by directly comparing progressively increasing
>> pigment/gum ratios with and without sensitizer/exposure, and found no
>> difference.
>> ______________________________________________________________________
>> Back to lurk,
>> Katharine Thayer
Received on Fri Apr 23 08:22:38 2004

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