Re: Printing gum with little pigment
Hi Marek again,
No, I wouldn't say that you see more dichromate stain on the less
pigmented gums because there is less pigment for the stain to show
through, because you see the dichromate stain even on areas where
there's no pigment. I would say it's a function of the less
pigmented mixes needing less exposure than the more pigmented mixes,
so the less pigmented mixes showed more dichromate stain (as a
function of superfluous development) after the same exposure,
although that dichromate stain seems to be eliminated with longer
development.
I wrote down the number of steps for each strip on a piece of paper
so I can compare them, since the comparison isn't on the same screen,
but I still can't make much sense of the comparison in terms of
comparing exposures and steps, although I'd agree as a general rough
conclusion that there doesn't seem to be a great difference in the
number of steps as a function of the pigment concentration.
I still can't remember where those comparison strips are, but I'm
either going to go through stuff looking for them, or make some
more. You've got me thinking. I think maybe it's an upside-down J-
curve or upside-down U-curve, where there's an optimal amount of
pigment that will give you the most steps, somewhere in the middling
range. But again, I'm thinking of actual value in terms of
reflection density, as in the demonstration I showed, and I'm finding
myself faltering on what the question is. I went back to your
original question, which is posed in terms of whether less pigment
"extends the range," which I would interpret to mean the range of
absolute value, not the number of steps printed, which has no
relationship to absolute value. So maybe we should define our terms.
Katharine
On Jan 16, 2009, at 3:53 PM, Marek Matusz wrote:
the more pigmented test consists of two sets. One developed for a
short peroid of time, 20-30 minuts, second a very long development,
hours, perpas 6 hours. You can see the dichromate stain in the
short development. The less pigmented gums also consist of two sets
with same development. You can easlily see much darker dichromate
stain in these Is it just because there is less pigment so you can
simply see the stain?
I was trying to have exposure timme/development/pigment decoupled
in these experiments. SO if for example someone says less pigment
needs more exposure (or less) I have done it or more development,
done.
Marek
> Date: Fri, 16 Jan 2009 15:34:57 -0800
> From: kthayer@pacifier.com
> Subject: Re: Printing gum with little pigment
> To: alt-photo-process-l@usask.ca
>
> Umm, thanks, but that still doesn't answer my question, sorry. Are
> the less-pigmented strips developed the same as the more-pigmented
> strips, was my question.
> kt
>
>
> On Jan 16, 2009, at 3:09 PM, Marek Matusz wrote:
>
> > Katharine,
> > Long development might be 4 to 6 hours and I tend to swoosh my
> > prints in the water too. My typical development is 15-30 minutes.
> > Marek
> >
> > > Date: Fri, 16 Jan 2009 13:59:39 -0800
> > > From: kthayer@pacifier.com
> > > Subject: Re: Printing gum with little pigment
> > > To: alt-photo-process-l@usask.ca
> > >
> > > Hi Marek, thanks for posting these. I will probably have more
to say
> > > about this later, because the issue of pigment and tonality
has been
> > > on my mind for quite a while too, but first a point of
> > > clarification: what do you mean by "long development" written
on the
> > > lesser pigent test strips; is this a different development
than for
> > > the other (more pigment) case, or the same? Thanks. BTW, I think
> > > this is a good and useful issue for discussion, and thanks for
> > > bringing it up.
> > > Katharine
> > >
> > >
> > >
> > > On Jan 16, 2009, at 9:33 AM, Marek Matusz wrote:
> > >
> > > >
> > > >
> > > > Hi all
> > > > I was waiting for a dry spell to bring this up. A while
back Judy
> > > > made a statement that printing gum with little or no pigment
> > allows
> > > > for a very extended range. I looked back through the Post
Factory
> > > > issues and really could not find examples. Hey Judy thanks for
> > > > sparking my interest.
> > > > Since I was messing around with the post-flash and was getting
> > good
> > > > results in extending tonal range of the print I decided to
do some
> > > > experimentation and actually print some test prints.
> > > > http://picasaweb.google.com/marekmatusz1/ExtendedGumRange#
> > > >
> > > > Two sets of tests are done with same water/gum/dichromate but
> > > > different pigment concentrations. I have made different
exposures
> > > > and tested two development times. I used indantrone blue which
> > is a
> > > > wonderful dark blue and non-staining. I can not see that low
> > > > pigment concentration extends the rane of gum print, to the
> > > > contrary it allows less steps to be separated on a standard
step
> > > > tablet. One of the tests is also a good illustration of how
> > > > delicate highlights with dark shadows can be printed with
the same
> > > > negative with the postflash.
> > > > Anybody else want to chime in. It would be great to see some
> > > > illustrations. A picture is worth a thousand words.
> > > > This contrast vs. pigment issue has been on my mind for a
while.
> > > > Marek
> > > >
> > > > Windows Live™ Hotmail®: Chat. Store. Share. Do more with
mail. See
> > > > how it works.
> > >
> >
> >
> > Windows Live™ Hotmail®: Chat. Store. Share Do more with mail.
> > Check it out.
>
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