Re: tonal inversion and pigment loads

Katharine,

I've thought about this a bit more and some comment below.

Regards
Yves

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, January 27, 2006 10:49 AM
Subject: Re: tonal inversion and pigment loads

>
> On Jan 26, 2006, at 10:43 PM, Yves Gauvreau wrote:
> >
> > The shortest exposure sample seems to have produce the worst
> > effect. On each
> > sample, after the "paper white" I presume (possibly staining also),
> > the tone
> > seems to reverses and peak at a rather uniform value even across the
> > different samples (if we exclude the numbers of course). To me this
> > suggest
> > something very similar happens to each sample and it seems as it is
> > not
> > (directly) related with exposure and not (directly) to heat either.
> > In other
> > words what doesn't add up is this uniform tone he gets above paper
> > white
> > (gray).
>
> This is what I've been saying all along, when I've said that these
> step prints don't show me anything about the inversion being a
> function of exposure, because all the different exposures do is push
> the inversion up and down the step tablet. The stain is the same tone
> no matter how much the sample is exposed, so exposure has no effect
> on the stain. The only difference is that you block up the shadows
> in the actual gum print part when you expose more. But the stain is
> not affected. The grey tone (including the speckling across the
> entire paper) is the stain.
>

It's like there is a competion between the light reaction and whatever other
"reaction" causes the uniform tone. As you say changing exposure just
changes where the tone starts but not it's value.

> > As for the numbers, well I have no idea, simple as that. On my step
> > tablet, which is not the same as the one Tom used, my number are a
> > light
> > pale gray in a black circle but still I'm sure his numbers have the
> > same
> > density and it should mean each number should print to exactly the
> > same
> > value and all I can say is it doesn't happen that way.
>
> This is interesting, isn't it, that the numbers in the denser areas
> of the step tablet seem harder to "stick" even though the density of
> all the numbers should be the same.

I don't know if you notice this but it's almost like, if there was more
steps above 21, we would see exactly the same thing happening to the
numbers, just shifting up like with the tone as exposure increase.

>
> >
> > The suggestion of printing a coat light on pigments and long on
> > exposure,
> > another medium on pigment and medium on exposure and a last coat
> > heavy on
> > pigment and short on exposure would seems at first, more and more
> > "illogical" as Spok would say. I already ear your complaints but keek
> > looking at the image below and you'll see in the 1m exposure that
> > the tone
> > present from about step #8 would cover-up step #8 and above on top
> > of what
> > is already there in the 2m sample and render practically useless
> > the 4m
> > sample because anything above step #8 wouldn't be white any more.
>
> Yes, if you printed a print this way, that's exactly what would
> happen. But you wouldn't want to actually PRINT, stained like this.
> You would either size the paper, if this is a paper-related stain
> with a normal pigment load, or you would reduce the pigment, if it
> was a stain due to overpigmentation, and then you wouldn't see this
> stuff at all; you would just see the normal tones of the hardened
> gum, no stain at all. That's my whole point.
>
> Katharine
>

I don't know, I agree with you that's not what we would want, but do we have
a choice? I assume it depends on the situation.

But in the situation presented here and I'm not making hypothesis, mostly
observations and one assumption: in a closer to reality situation the
negative wouldn't have a Dmax of 3.0, maybe a maximum density equivalent to
step 6-7 to maybe 8 or 9 at most. The 1m steps 4 to 7 show relatively the
same tone if any and would probably not add much of anything on the 2m and
4m sample at the same step number of course and I'm not suggesting either
that the darkening would be linear. A similar observation can be made for
the effect of the 2m sample on the 4m one. If as I suggested the Dmax of our
"real" negative is no higher then step 7 as would be required in this case,
there wouldn't be any kind of stain caused by the phenomenon we see above
"paper white" in these samples. Here I assume changing anything to the
emulsion, would require us think this all over again.

This is probably why Terry King (and others) if I recall correctly, said to
use a negative with a density of 0.7 (2 1/3 stops or just less then 5
steps). With what we just said, observed and from (yours, certainly not
mine) empirical experience I would say use thin negatives and you wont
experience this problem.
Received on Fri Jan 27 12:23:55 2006