Re: tonal inversion and pigment loads

Katharine,

I plead guilty, hope that's correct, as I and many of us here do all the
time we speak about things and think about others without giving much
details. Here we where talking about step-tablets inversion (2) and in my
mind I was thinking of an actual negative where the Dmax would be
appropriate for gum printing. In others words no 17 steps of dark useless
tone.

Regards,
Yves

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, January 28, 2006 12:20 AM
Subject: Re: tonal inversion and pigment loads

>
> On Jan 27, 2006, at 7:44 PM, Yves Gauvreau wrote:
>
> > 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.
>
> Actually I can't, because I'm not sure what you are saying. Are you
> saying that the answer is that you should expose so long that you
> push the print tones all the way up to 21 so that there's no room for
> stain, making all the steps from 1 to 17 black? And then just develop
> for the next month to get rid of the tone back down to the four
> actual tonal steps? This doesn't seem to me a reasonable thing to
> do. And maybe that's not what you're saying.
>
> To me the place in the middle where there's less tone, is just the
> end of the normal tonal scale, the lightest highlights, and then the
> stain starts. The hardened gum in the lightest steps forms a bit of
> a resist to the stain, less with each ascending step, and so the
> stain gets darker with each increasing step. That's all it is.
>
> >
> > 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.
>
> Well, you can't take it out of the thing you've just made, but you
> can sure fix it for the next time, by making sure that you remedy the
> thing that is causing the stain; either the paper needs more sizing
> or the pigment load needs to be adjusted. I keep taking this page
> down but someone keeps wanting it back up, so here it is again, the
> PV 19 inversion I showed a couple of weeks ago. By reducing the
> pigment load by 1/3 and reprinting, I made a nice magenta layer of a
> tricolor, shown directly above the inversion, although still just a
> touch too pigmented. In other words, it's not that hard to fix an
> inversion, just fix the problem that's causing the stain.
>
> http://www.pacifier.com/~kthayer/html/tricolorfun.html
>
> And there's another example on my pigment stain page, in the tonal
> inversion part: I show some tonal inversions with burnt umber, and
> then there's a link to a similar image of the same subject, printed
> with less burnt umber, which prints a perfect tonal scale with no
> stain, to show the remedy for the inversion. If you don't want to
> read the information, just scan the second paragraph under the
> inverted images for the blue link "here." to see the comparison image.
>
> http://www.pacifier.com/~kthayer/html/stain.html
>
> The point being that fixing inversions is a snap, just fix the stain
> and the inversion goes away.
>
> >
> > The step tablet should be opaque to light for steps and nothing
> > should print
> > above the first "paper white" step.
>
> Yes.
>
> > 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).
>
> And that tone, is stain.
> Katharine
Received on Sat Jan 28 11:18:56 2006