Re: tonal inversion and pigment loads

Katharine,

I should have explained myself more clearly on this. If you look at Tom
image again, you'll see that as the exposure increases, the number of "paper
white" step(s) gets lower and lower suggesting that the lowest exposure
(time) must not be allowed to invert at all, otherwise you get what is
called "inversion" stains (for now). I think we can all agree on that.

I'm not sure there is away to get ride of the "inversion" stain otherwise
Tom would have taken them out and this wouldn't even be a problem otherwise.

It would seem logical to think that as the negative density increase you
will need both an increase in exposure to push the "inversion" out of the
way and the difference in exposure from coat to coat would need to be
minimised. In the limit they may very well be all the same. All this is
feasible, sure but I think it would involve more work and may be much harder
to control. We all learned it's easier to make a print starting with a
negative matching the paper (process print) we are doing. I agree with you
in advance that I could find a way to say this better but I would think this
shouldn't cause a problem.

The step tablet should be opaque to light for steps and nothing should print
above the first "paper white" step. The observation we all made is that Tom
test shows a relatively uniform tone above these "paper white" steps
whatever the exposure (in these cases). I agree 3 samples is not much to go
by but that's what we have.

Regards
Yves

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, January 27, 2006 1:45 PM
Subject: Re: tonal inversion and pigment loads

>
> On Jan 27, 2006, at 10:25 AM, Yves Gauvreau wrote:
> >
> > I don't know, I agree with you that's not what we would want, but
> > do we have
> > a choice?
>
> Of course we do. There's no necessity to print stained prints at all,
> unless you really want to, and most gum printers never see any of
> these phenomena, and I've produced them recently for test purposes
> only out of intellectual curiosity. As I said, if you get pigment
> staining, if the stain is paper-related, size the paper; if it's
> related to overpigmentation, reduce the pigment. Voila, stain-free
> prints. there's no need to make this so complicated.
>
> BTW, a thin negative isn't "required" it's just what works best for
> many people, but you can use any kind of negative for gum
> successfully; the rules for eliminating stain above apply regardless
> of the negative. Unless, of course, the negative is so thin that its
> densest parts fail to keep the gum under them from hardening, but
> that's a different issue, and FWIW I've never yet seen a negative
> that thin in my own practice. But it would depend on the light, of
> course, what constituted a "too thin" negative.
> Katharine
>
>
Received on Fri Jan 27 21:43:06 2006