Katharine,
It is clear that lower pigment concentration will result with lower DMax, and lower density range which you have nicely illustrated. The real question that I asked can not be really answered well with a real negative, because if you develop for highlights a number of shadow steps can be blocked, which can be difficult to spot on a real negative.
Marek> Date: Fri, 16 Jan 2009 15:58:28 -0800
> From: kthayer@pacifier.com
> Subject: Re: Printing gum with little pigment
> To: alt-photo-process-l@usask.ca
>
> Agree with Marek here.
>
> Marek, I'm trying to remember where I have a set of such test strips
> that I could quickly scan for you.
>
> In the meantime, I have something a little different, that may or
> may not be helpful to the discussion. What I have is reflection
> density readings for a range of pigment concentrations. This doesn't
> show the number of steps on a Stouffer tablet, but it does show the
> actual tonal range (of course for gum there's no particular
> connection between Stouffer steps and tonal densities).
>
> For my demonstration I used PBk11, which has become my favorite
> black; I printed it at six different concentrations. The two
> lightest concentrations gave the shor
test tonal range, .50 and .62.
> The next three all gave a range of .75, each moving progressively
> down the scale. The heaviest mix doesn't really count, because I
> overexposed it and then subjected it to extreme measures of blasting
> it with hot water under pressure and scrubbing it with a wire brush
> to bring out the tonalities; it came out at a range of 1.00, but as I
> said, I'm not sure it counts because the tones weren't developed
> naturally but forced out of the gum by sheet will power and cussedness.
>
> Anyhow, I printed a sample print rather than using test strips, just
> because I think most people who aren't used to using step tablets
> find an image more intuitive to understand; those test prints and the
> density data are here, the first visual on the page:
>
> http://www.pacifier.com/~kthayer/html/tonality.html
>
> Katharine
>
>
&
gt;
> On Jan 16, 2009, at 3:05 PM, Marek Matusz wrote:
>
> > Loris,
> > Here is where the argument breaks down. What you consider a weak/
> > moderate pigment I might be using and defining as strong. The only
> > way for you to convince yourself of the validity of your assumption
> > is to cut the pigment concentration in half or quarter and print
> > something side by side. I am looking for people that have done it
> > already and can share the actual prints/test strips.
> > Marek
> >
> > > Date: Fri, 16 Jan 2009 22:01:40 +0200
> > > From: mail@loris.medici.name
> > > Subject: Re: Printing gum with little pigment
> > > To: alt-photo-process-l@usask.ca
> > >
> > > Thanks for sharing these Marek.
> > >
> > > I regularly print gum from negatives calibrated for Cyanotype,
> >
something
> > > like log 1.5 ES (= 15 steps with the 31-step tablet - each step =
> > log 0.1)
> > > using weak / weak-moderate pigment concentrations, getting full
> > detail
> > > starting from shadows up to the highlights. So I definitely
> > believe in
> > > less pigment = more range -> it's in parallel to my experience...
> > >
> > > Regards,
> > > Loris.
> > >
> > >
> > > 16 Ocak 2009, Cuma, 7:33 pm tarihinde, Marek Matusz yazmış:
> > > >
> > > > 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
> > > > e xtended 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
> &
gt; separated on
> > > > a standard step tablet. One of the tests is also a good
> > illustration of
> > > & gt; 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™: Keep your life in sync. Check it out.
>
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