From: Cactus Cowboy (cactus@tritel.net)
Date: 02/08/02-11:49:52 PM Z
Dear Judy:
Paul Anderson may have had "bad habits", but that does not mean he created
or caused a pigment stain problem. Most gum printers will agree that too
much pigment in the mix will create an undesirable stain. That none of
Anderson's contemporaries (excepting Casell in 1911) mentions staining as a
problem shouldn't mean much to you.... After all, you did dismiss the past
with the following quotation:
> "HISTORY IS MORE OR LESS BUNK..."
>
> That's one of the more famous sayings of that great American Gum Printer,
> Henry Ford
Let's focus on the present, and what we've learned from personal experience.
I've used 30% ammonium dichromate and 10% potassium dichromate solutions
extensively. Using the same pigment/gum mixture, I've made identical test
exposures with both AD 30% and PD 10% respectively. The results? AD yields
muddier, lower contrast prints. PD will produce deeper shadows, more
contrast, and a shorter scale. Even after adjusting exposure to negate the
difference in emulsion speed, AD will create a very slight apparent increase
in pigment stain as compared to using PD. But pigment/gum ratio has a far
bigger impact on staining than sensitizer does.
Judy writes:
> I suppose some folks reading this will still demur. So under separate
> cover I outline a few simple tests for proof. Meanwhile, I note two
> bizarre phenomena that shed more light on the process. First, am I the
> only one who has made a test strip with some weirdo brand of watercolor
> that likes to stain and found that whites cleared up to step 10 or so,
> then began a reverse scale, building tones IN PIGMENT STAIN, in nice stair
> steps, but now in reverse, lightest at step #11, darkest at the top? At
> first I suspected a light leak, then realized that, being so consistent,
> it had to be the material itself. I asked the list, under some subject
> line like "Gum Mystery," probably in early 1995. No answer.
No, you're not the only one. I wasn't on this list in 1995, but I'd
experienced this phenomenon over 10 years ago. I saw the same effect using
Sennelier Mars Black (dry pigment) mixed 1g/20ml gum with PD 10% sensitizer.
Sennelier Mars Black is an iron oxide pigment that's prone to heavy
staining.
You like to come off as a 'new authority', someone who's making exciting
discoveries, Judy. I (and I suspect many others) have made the same
observations and have had the same experiences you've had in gum printing.
Indeed, nothing you've offered in your magazine or on this list regarding
gum printing has been news to me. Much of what you've written I've doubted,
due to your imprecise methodology, e.g. "Choose a tube watercolor that likes
to stain. Mix enough of it into 10 cc of gum arabic to make a strong color."
What exactly is "strong color"? How is the pigment being measured? By eye?
By weight? By volume?
You've frequently maligned the writings of Anderson, Crawford, and Scopick
regarding the gum-pigment-ratio test. How many times do you need to beat a
dead horse..... We all understand that sizing, type of paper used,
sensitizer, dilutions, temperature, and exposure have an impact upon
staining. But that does not mean the test is meaningless or without value.
It is a quick and easy way to determine an approximate *starting point* for
gum/pigment ratio.
How many gum printers out there are using Burnt Sienna and Thalo Blue? How
many of you use them at exactly the same pigment/gum ratio? LOL! Any
'doubters' should try the pigment-gum-ratio test (follow instructions given
by Crawford or Scopick) using these two pigments. If any of you don't see
strikingly different results, I'll eat my cowboy hat!
It's apparent that you favor a casual 'mix by eye' approach Judy. Given
that, the very notion of a measured gum/pigment ratio is meaningless to you.
I'm not knocking your printing methods as long as they work for you and
you're happy with the results. If you can't or won't appreciate the value
of using a precise approach to gum printing, please don't criticize those
who do.
Best regards,
Dave Rose
Big Wonderful Wyoming
----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Friday, February 08, 2002 2:54 AM
Subject: a funny thing/ Re: Anderson again two
>
> For folks with some interest in the pigment stain question, this & a
> couple more I'll send tomorrow (well it is tomorrow, but you know what I
> mean), have got what may be some new info, and come to about what I
> can/will/should say on the topic. For those not interested, delete
> instantly.
>
> J.
> ===============================================================
>
> A funny thing happened on the way to this umpteenth "explanation" about
> pigment stain. I noticed what I should have noticed long ago. And that is,
> as far as I can tell, Paul Anderson *invented* pigment stain. He got it
> from bad habits, then found a "cure" as bad as the disease -- and, such is
> the nature of "art" photography and the zeitgeist that this debilitating
> error remains a centerpiece of OUR gum literature, 72 years later.
>
> This flash of understanding arrived with incredible sloth, of which I do
> not boast. But ultimately, I checked the gum chapters & articles in a
> congeries of books, pamphlets, magazines, annuals, manuals, formularies,
> dictionaries & encyclopedias back to 1896 (and invite whoever has any
> available to do likewise). I can't say I found *nothing,* but I found
> *almost* nothing. That is, in dozens of sources, only one even mentioned
> "pigment stain" before Anderson. That was Cassell, in 1911: "The paper
> must be well sized, in order that the pigment may lie on the surface and
> not sink into the substance of the paper so as to stain and degrade the
> high lights." Honesty compels me to admit I did not check every single
> volume of every single annual (and of course there are many gaps on the
> shelf), but most "process" entries remain unchanged for a decade, so I
> figure 5-year intervals covers it. Judging by the quality of their other
> observation, I don't think folks would have failed to notice pigment stain
> if they'd had it. (But if someone finds a stain alert or lament I missed,
> please send word.)
>
> Meanwhile, I re-read Anderson: Now it leapt out -- he's using almost ONE
> HUNDRED PERCENT sodium dichromate solution for sensitizer. He mentions
> potassium dichromate at 10%, but "prefers" sodium dichromate, 960 grams in
> 1000 cc, because it's "quicker." ON TOP OF WHICH, he uses two parts of
> this Extreme Sensitizer to one part gum. In Henney & Dudley, it's even
> more, 35 cc dichromate to 15 cc gum. On top of which, he likes unsized
> paper. Is it any wonder the man had pigment stain? (His TEETH should have
> pigment stain.)
>
> Before, during, and after Anderson, the most usual dichromate was 10%
> potassium, most often in equal parts with gum. Even today I know of nobody
> using stronger than 30% am di. The ratio of gum to sensitizer varies, from
> equal parts, to 1 to 3, or 3 to 1. But, since the dichromate controls the
> stain (as I shall explain, be patient), Anderson had a problem. Did
> anybody else? Not that they mentioned. (I've taught or helped, done
> trouble shooting with, gotten calls or e-mails from a lot of printers &
> students, not ONE of whom arrived saying, "Oh woe, I cannot get rid of
> this pigment stain." And no case of staining I ever saw wasn't fixed by
> recoating the bad size, changing the paper or gum arabic, giving up the
> anorexic negative, abandoning the hair dryer, or losing the cheapo student
> watercolors. Lowering pigment was beside the point.)
>
> I admit I have said on every possible occasion (to small thanks) that the
> dichromate is part of the equation. Actually, it *controls* the equation.
> But did you ever wonder why none of the legions dutifully working up this
> gum pigment ratio thing, dram by dram (one dram = 3.5 cc), with such
> "scientific" care and keen observation ever noticed that adding the
> sensitizer cancels out everything they've spent those long hours
> precision-testing?
>
> It seems one person did: William Crawford ! In "Keepers of Light" he says,
> "The dilution of the pigment/gum mixture by the sensitizer actually has no
> effect on the staining." Actually, he's whistling in the dark. "What is
> important," he says, "is the relationship between a specific amount of
> pigment and a specific amount of stock solution." And he wishes us to
> believe that these smart pigment particles know which water molecules came
> in with the gum and which came in with the sensitizer, so they can have a
> proper relationship !? I don't think so. Scopick recently told this list,
> as proof of the excellence of the G-P-R test, that his students never had
> any trouble with it. Truth to tell, I also failed to pick up on the
> nonsense just quoted until I was experienced enough to recognize
> gum-o-babble when I saw it.
>
> I suppose some folks reading this will still demur. So under separate
> cover I outline a few simple tests for proof. Meanwhile, I note two
> bizarre phenomena that shed more light on the process. First, am I the
> only one who has made a test strip with some weirdo brand of watercolor
> that likes to stain and found that whites cleared up to step 10 or so,
> then began a reverse scale, building tones IN PIGMENT STAIN, in nice stair
> steps, but now in reverse, lightest at step #11, darkest at the top? At
> first I suspected a light leak, then realized that, being so consistent,
> it had to be the material itself. I asked the list, under some subject
> line like "Gum Mystery," probably in early 1995. No answer.
>
> Then a similar, even stranger effect -- a 21-step with tone up to step 4,
> then perfectly clear whites in steps 5 through 9, then HEAVY staining in
> steps 10 through 21. Not possible? It's in Post-Factory #3, page 38.
> Finally, Mike Ware (who was on the list in '95) offered a plausible
> theory: Pigment stain occurs when the emulsion isn't viscous enough to
> stay on the surface of the paper, but soaks at least partway into it,
> where it is hardened by the dichromate (as may happen even without
> "exposure"). In fact, any concentration of pigment can sink into the paper
> & be held there, if other conditions are right. In this case, steps up to
> #9 got sufficient exposure to become viscous enough to NOT soak in, the
> ones after that (higher numbers) didn't.
>
> Which is to say, exposure is part of the equation. AND so is the
> dichromate. The hardening happens at or just under the surface of the
> paper, where there is relatively more dichromate, probably because it
> soaks in more than the fuller-bodied ingredients. (Anderson's diagram
> showing unhardened emulsion oozing out through the hardened surface is
> almost certainly also wrong. If there were unhardened emulsion under a
> crust, the crust would most likely flake off.)
>
> I did some cute little prints in that reverse-step technique --
> "direct-positive gums." (also in P-F #3, p. 38.) But it takes a really
> dense negative, a strong stainer, and long exposure. Here's a simpler way
> to prove the point about viscosity and stain. Coat two test strips with
> any gum-dichromate-pigment combo that's not a big stainer, but give the
> mix for one of the strips twice the pigment of the other -- gum and
> sensitizer in the same amounts, only the paint is increased. Expose &
> develop. Odds are, the strip with twice the pigment will stain less. The
> extra pigment makes the emulsion more viscous, so it doesn't sink into the
> paper. (Of course, if you double pigment in a combo that stains to begin
> with, you may expect double the stain; but the *relative* stain is no
> greater.)
>
> I had by then figured out, & Mike Ware confirmed, that "the usual stain
> test to get a pigment-to-gum ratio as described in the books is
> [essentially] meaningless," since it does not duplicate conditions of the
> actual event. And, as noted, adding dichromate to pigment-in-gum may cause
> stain just by being there. (I feel a certain discomfort quoting Mike Ware
> in this, invoking the holy name, as it were, but failing to implies I
> thought of things on my own that I'd had no clue about. I note also that,
> onlist and off, he distinguished between what he knew and what he
> hypothesized. I have added a few extensions and interpretations, however,
> for which he is not responsible.)
>
> Meanwhile, Pete, who at last report claimed to still believe in the G-P-R,
> has cited the "masterly work" of, among others, Joe Smigiel. Here's Joe,
> writing to the list, August 18, 1998, subject line "Gum Print Questions,"
> QUOTE: "I suspect [there are] many people out there who have simply given
> up on gum when it didn't work as explained in the popular texts. If I had
> not seen some of Steichen's work in person, I might have been among that
> group. My earliest experience was frustrating..." Demonstrations seemed to
> all be high-contrast lith negs and poster effects. Now, that "high
> contrast poster look seems more prevalent, just as the stain test
> persists..."
>
> Step One in his technique, Joe said, is "mix as much pigment into the
> emulsion as you can without causing flaking." Step 2, "Use about twice as
> much gum as sensitizer."
>
> cheers,
>
> Judy
----- Original Message -----
From: "Judy Seigel" <jseigel@panix.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Friday, February 08, 2002 3:19 AM
Subject: 3 little tests Re: Anderson again two
>
> The Tests
>
> Science, the newspaper tells us, has now got a computer program that puts
> data from work in progress into code, so researchers do not know how
> things are coming out. The human desire to have results go one way or
> another apparently affected ability to read tests accurately.
>
> In a similar vein, I have read that studies by doctors who like exercise
> "proved" that heart patients benefit from exercise, and studies by doctors
> who don't like exercise "proved" the contrary. Which is to say, my tests
> make it dramatically clear beyond the possibility of doubt that the
> stronger the dichromate in an emulsion mix, the stronger the pigment
> stain.
>
> They should also prove that you cannot tell the pigment-stain story
> without the dichromate story, that differences in dichromate cause
> differences in pigment stain. You will also see that they are so simple
> and obvious, it's hard to understand why something along these lines never
> replaced the gum-pigment-ratio event that will not die.
>
> The Dichromates:
>
> Mix dichromate with distilled water. Potassium dichromate is soluble up to
> about 10% (10 grams in 100 cc). Ammonium dichromate is soluble up to 30%
> (30 grams in 100 cc). Sodium dichromate is soluble to *around* 100% (my
> books refuse to make up their minds). The range of concentration possible
> with the potassium dichromate is too small to read results easily, so use
> either sodium or ammonium.
>
> The volumes given are far more than needed for test strips, but are easier
> to measure. If you have droppers or pipettes or syringes for measuring
> small amounts, choose your own volumes. All tests should be with the same
> dichromate (ammonium or sodium), so that differences can *only* be due to
> test variables. The figures given are for ammonium, and assume a 30%
> solution. In a cool room, some dichromate may precipitate out. That's OK,
> there's range to spare.
>
> The Paper
>
> Since we're TRYING to show stain, ideally the paper should be shrunk & not
> sized. A surface size on paper that's never been wet can forestall stain
> on many first coats; the water washes it away & raises the nap, after
> which it stains more (unless given a coat of size).
>
> Procedure:
>
> Make up 50 cc of a 30% solution of ammonium dichromate (15 grams in 50 cc
> water), and 50 cc of a 10% solution of ammonium dichromate (5 grams in 50
> cc). Wait a day before doing the tests, so the crystals will be fully in
> solution.
>
> Test #1: Choose a tube watercolor that likes to stain. Mix enough of it
> into 10 cc of gum arabic to make a strong color. Combine half of this
> gum-pigment mix with 5 cc of the 30% dichromate and coat two strips of
> paper. Combine the remaining half of the gum-pigment mix with 5 cc of the
> 10% dichromate solution and coat two more strips. Reserving one strip of
> each concentration for the next test, expose one of each concentration
> under a 21-step for a bit longer than your usual gum exposure. Develop
> face down in water for half an hour, let dry and compare. Although the
> gum-pigment ratio remains the same, the stain will change with the
> dichromate.
>
> Test #2: The 10% strip may have been too underexposed to be read clearly.
> Expose the remaining two strips for twice the time (or as much longer as
> you figure it will take for the weaker sensitizer to get enough tones to
> show stain). Develop and compare as in #1.
>
> The 30% strip should have more pigment stain than the 10% strip. Yet the
> gum-pigment ratio has remained the same.
>
> Test #3: Coat two strips as above, except with half as much pigment in the
> gum. Expose for the compromise time arrived at in test #2. The total
> amount of stain will be less than in test #1 (which has more pigment), but
> the difference in stain between the two strips should be comparable.
>
> Try any other papers on hand and compare.
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