Re: Gum hardening -- top down?

On Wed, 5 Apr 2006, Sandy King wrote:

> Judy,
>
> So, let me understand. You are able to make gum prints with one exposure that
> have both high Dmax (log 1.80 or above as is possible with carbon), and a
> complete range of tones from the shadows to the highlights?
>
> If so, show them, and better, provide working details of how you achieve
> this.

Sandy, you don't deserve a civil answer on this, because I've already
GIVEN that information, but I choose to put this matter to rest (when
folks know everything already, it's awfully hard, or let's say beyond my
meagre powers, to impart anything new) -- So... did you notice that I
cited Post-Factory #6? In "Serious One-Coat Gum Printing," page 33, I
show a pretty fair one-coat gum printed by a first-semester undergraduate,
& one of my own, also some tests showing variations according to size,
exposure & development. I discuss the variables at issue, and useful
strategies (including at least one size formula).

But not to simply cite my own prowess (ahem!), my e-mail pointed mostly to
Robert Demachy and his school of one-coat gum printing -- though perhaps,
being French, he doesn't count? (We could call them "Freedom Gums.") Or
maybe you haven't seen his prints?

More likely, I waste my key strokes. Bob Schramm, seeing them in Paris,
declared them the most beautiful gums he'd seen... wish I'd seen them, but
having read and re-read Demachy's essays, I find him totally credible --
also surprisingly lyrical and comprehensive. He *got* the whole deal right
off.

What I'd ask you, however, is what message from on high (sermon on the
mount? call from your inner Stieglitz?) authorizes you to declare the
*proper* D-max for a gum print?

Do you know the proper colors? Dimensions? Subject? I myself don't know
any of those proprieties (silly me), and don't even measure D-max of
prints -- not having a reflection densitometer, or even caring. I do
negatives with (transmission) densitometer. Prints are by look... In fact
"D-max" can be too great for a high-key print.

But you might do well to consider a point made very nicely by none other
than William Mortensen (as I recall, in "Mortensen on the Negative." But I
quoted it in a P-F, and I daresay it's in the index on the website). To
the effect that the highest value in a print "becomes" white, and the
darkest value "becomes" black, He also shows some evocative examples of
what we forget at our peril. At the very least, defining D-Max in advance
abdicates a wonderful tool. Of course Mortensen is kitsch, but surely
when a Richard Prince sells for almost the equivalent of the national debt
we can overlook that sin. Mortensen was a fine technician; evidence also
suggests that he pioneered the Zone System system.

(However, to quantify my own one-coat for the quantification-minded, I'd
say average 8 steps on a 21-step.)

I'm going to mention some observations about dichromate behavior in a
separate e-mail, and then skip town, but first, I unwisely, no doubt,
point out an error by the other King on this list -- who explained:

QUOTE: "The very reason why pigment is adjudged to be too much is that
the light cannot get to the lower layers so that remain unhardened. That
is why too heavily pigmented mixtures fall off."

I admit that a sarcastic reply comes to mind, but I'll repeat the point I
was in fact making and leave it at that: A propos of the apparently short
scale of a coat of heavily pigmented gum (and I illustrated this in
several P-Fs, most clearly perhaps in Issue #2):

The tones of the lower steps are all at D-max because of the heavy pigment
(ie., "blocked up" to use the traditional term), so that, let's say, the 3
or 4 or 5 lowest steps appear as one. Often a long soak will open up
those steps, possibly therefore adding to the range -- BUT, depending on
the mix, the paper, the size, and the will of the gods, the top steps may
dissolve at the same or even faster rate, for a net increase of zero
steps, or even a loss. One of the issues I address in the "One Coat"
article is how to finesse that exchange.

One of the ways Demachy addressed this, BTW, is by judicious drops of
water to bring out detail without long soaks. I imagine Chris's water
spray is a related strategy... but all things are different with a digital
negative, at least IME. So that's not this story.

> Or more broadly put, if anyone can do this, show your work and give the
> working procedures.

See above.

> As for your comment, "As for exposure from the back proving top-down
> hardening -- surely you jest --do you expect the hardening to occur on the
> back of the paper?" I am really left with little to say, except that this
> statement proves what an incredibly deficient understanding you have of the
> theory, practice and mechanism of colloid photography.

I really am such a dummy, it's awfully generous of you to even talk to me.

> Finally, you remark, "Meanwhile, FWIW I have tried that exposure from the
> back thing for other purposes... After two hours of exposure NOTHING occurred
> & I figured the dichromate would harden from old age -- and me too -- before
> it "worked," and gave up. So when you say "very long," you mean about a
> week?, in which case dark reaction could be theorized instead..."
>
> The answer to the above is, you need to expose for as long as necessary. If
> two hours was not long enough, expose four, or six or ten or twenty-four
> hours. I know people who have made beautiful carbon and gum prints by
> exposing to a north light for a week or more. The fact that nothing happened
> in your experiment proves nothing.

I'm older than you Sandy, and therefore have less time to waste,
especially on such dubious propositions.

> Before anyone attacks my comments, please bear in mind that I am not making
> any claims of superiority as to how to best make gum prints. My only claim is
> that the mechanism of hardening is from the top down. And there are many ways
> to test this that will demonstrate this as fact. But people knew this as fact
> in the middle of the 19th century, so don't blame me for the bad news.
>
> Sandy

True, my memory could be going in old age, but I don't recall reading that
about gum printing, only as a reason for carbon transfer and to explain
the difference between carbon and direct carbon. But then again, gum
printing wasn't in general practice as an art form until ca 1894, or
practically the 20th century, so "middle of the 19th century" lit isn't
much use.

Judy
Received on Thu Apr 6 21:01:56 2006