Re: tonal inversion and pigment loads

On Jan 27, 2006, at 10:30 AM, Ender100@aol.com wrote:

> Katherine,
>
> Actually, if this is true that increased/decreased exposure does
> move the inversion "up and down" the scale, then this does tell you
> something—that it is related to exposure and possibly occurs only
> at one portion of the H&D curve of the gum mix. However, the fact
> that the numbers are all getting the same exposure (Maximum) and
> they ALSO reverse would say something to the contrary—but this
> effect on the numbers may be a second clue saying that there are
> two variables working here, unless adjacent emulsion comes off and
> rips the numbers with it...

I think maybe you're missing my point. Yes, in an inversion, the
stain sticks only where there is less hardened gum, in other words
where there is less relative exposure. That's a given, as I keep
saying. As you expose more, you move that part farther up the
tablet, but it doesn't change anything about the stain itself. You'll
have to develop longer to open the shadows on the more exposed
strips, but if you developed all three to the same four tones in
the gum image, the stain would still be the same on all of the prints
when you were done, just as it is the same on all these strips no
matter how long they are exposed and how far up the shadows are
blocked. So, exposure doesn't have any effect on the ultimate
stain, so I don't see how it can be said that stain is a function of
exposure. (BTW, an inversion is only a small increment in the total
continuum of pigment stain; with more pigment, as I showed last week
with lamp black, which is now incorporated into my permanent page on
pigment stain, you won't see an inversion any more but just a total
overall stain that overwhelms the entire image, no matter how long
you expose it.)

As to the "inversion" on steps 17-21: There isn't any hardened gum at
all above, say, step 10, as the stain is the same tone from there on,
so on all the steps from 10 on, all the gum emulsion would wash off
the steps entirely except for the numbers, leaving a tone made of
stain on the steps. Why the numbers wash off on steps 17-21 is a
mystery, given that the density of all the numbers should be the
same, and given that from step 10 on the emulsion should wash off the
steps equally, but it's still all about stain, and I don't understand
all the excitement about it, when the remedy is so simple: don't
print stain!

>
> I haven't been following this discussion closely, so I may be
> missing facts/issues you folks have already considered and
> eliminated. Is this only occuring with a certain pigment/pigment
> color combination?

Nope. I've seen it and shown it with burnt umber, lamp black, and
PV19. Tom has shown it with lamp black and ivory black.

>
>
> If so, is it possible that pigment contains something that is
> changing the chemical reaction?

Not likely. This is about STAIN! Guess I'd better go clean the studio
before I start sputtering.

Katharine.
Received on Fri Jan 27 13:15:38 2006