U of S | Mailing List Archive | alt-photo-process-l | RE: Printing gum with little pigment

RE: Printing gum with little pigment



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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