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.

> 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.

>
> 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
Received on Fri Jan 27 09:51:51 2006