RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/03/05-06:10:03 PM Z
Message-id: <20051004001004.CCA2776F28@spamf4.usask.ca>

Joe, if you have seen Dick's book, he does go into it all quite in depth.
But he does choose to set his black at the 90 % Sandy mentions. This 90% is
straight from Phil Davis and Beyond the Zone system. I don't know if it
really that relative to the platinum process. But As you can see, Sandy and
I will work in some real step wedge, print density numbers. I can evaluate
somewhat better from those and he will from mine.

Dick's underlying chemistry is not the same as mine so things may be more
than just a matter of semantics.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 
> -----Original Message-----
> From: Joe Smigiel [mailto:jsmigiel@kvcc.edu]
> Sent: Monday, October 03, 2005 5:57 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Best CI for process
>
> Eric and Sandy, et.al.,
>
> I'd just like to comment that this is very confusing to a bystander.
> For example, the post below implies steps 1-7 all have the same density,
> i.e., "dmax", and yet the question asks if only "step(s) 1,2,3, were all
> of the same density?" Reading this stuff it sounds like there is an
> arbitrary dmax and then a different absolute dmax. Is there?
>
> Is there an ISO standard for reporting dmin, dmax, and density range?
> If so, can you point to a good source that would explain it (maybe Phil
> Davis BTZS or...)?
>
> Could this just be simplified to a statement such as: only steps 7-19
> are separated on the print. This certainly implies that shadows at
> steps 7 and below are blocked and the same tone (dmax), and that paper
> white occurs at step 19 with the remainder blocked and printing white
> also. By extension, 12 steps have printed as separated values giving a
> density range of 1.80, or would/should you count 13 distinct steps on
> the paper and a range of 1.95? There has to be a standardized, simpler,
> less ambiguous way of reporting these results.
>
>
> Joe
>
> >>> e.neilsen@worldnet.att.net 10/03/05 6:08 PM >>>
> Well, that wasn't so hard. When I go to the unblinking eye site where
> you
> show your pt/pd test, I see dmax at step 7 and and dmin and step 18 ,
> showing 12 steps with an ES of 1.8. Step 1,2,3 were all of the same
> density? And paper white is at step 19?
>
>
> If, so that is not where I am counting. Steps 1 and 2 still show
> separation
> and step 21 is darker paper white in my ES.
>
>
> Eric Neilsen Photography
> 4101 Commerce Street
> Suite 9
> Dallas, TX 75226
> http://e.neilsen.home.att.net
> http://ericneilsenphotography.com
>
> > -----Original Message-----
> > From: Sandy King [mailto:sanking@clemson.edu]
> > Sent: Monday, October 03, 2005 4:49 PM
> > To: alt-photo-process-l@sask.usask.ca
> > Subject: RE: Best CI for process
> >
> > Eric,
> >
> > By intelligent I mean the ability to talk apples to apples.
> >
> > We have not been doing that, and based on your description of how you
> > count the steps of a step wedge I now understand why. If I were
> > counting everything but absolute Dmax I too would be reporting am ES
> > of 2.4 or above.
> >
> > Sandy
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > >Sandy, If by intelligent you mean that we all need to agree that
> there
> > are
> > >not absolute places to start to evaluate a curve, or straight line?
> There
> > >are not absolute places. There are points of absolute density. ES and
> CI
> > are
> > >based upon interpretation of useful information that can be
> arbitrarily
> > >applied.
> > >
> > >
> > >If you are only printing 12 steps on a 21 step scale, one that has
> > densities
> > >range from 0.0 to 3.0, with step 1 and 2 blending and you are only
> > getting
> > >to step 13 before paper white with pure palladium, then our processes
> are
> > as
> > >different in capabilities as to be creating confusion.
> > >
> > >
> > >
> > >
> > >
> > >Eric Neilsen Photography
> > >4101 Commerce Street
> > >Suite 9
> > >Dallas, TX 75226
> > >http://e.neilsen.home.att.net
> > >http://ericneilsenphotography.com
> > >
> > >
> > >> -----Original Message-----
> > >> From: Sandy King [mailto:sanking@clemson.edu]
> > >> Sent: Monday, October 03, 2005 4:11 PM
> > >> To: alt-photo-process-l@sask.usask.ca
> > >> Subject: RE: Best CI for process
> > >>
> > >> Clay,
> > >>
> > >> I do indeed use a figure of 90% black when plotting with the
> > >> Winplotter program. This gives very close to the same value as
> when
> > >> measuring a step wedge print in the way I just described to Mark,
> > >> i.e. from the first step about pure paper white to the first
> shadow
> > >> step that merges visually with the next one.
> > >>
> > >> What I have been trying to figure out from the beginning of this
> > >> thread is is, 1) are Eric and Emille using options which give a
> much
> > >> longer ES than I am used to in my work, or 2) are we simply using
> > >> terminology and practice that does not allow us to communicate
> > >> intelligently on the subject?
> > >>
> > >> I still have not figured out which is the case, though some of the
> > >> recent communications are making me lean toward the second of the
> two
> > >> possibilities.
> > >>
> > >> Sandy
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> >Is this exposure scale derived by counting 21-step Stouffer
> tables
> > >> discernable
> > >> >steps and multiplying by .15? The reason I ask is that I'm
> betting
> > Sandy
> > >> is
> > >> >using the BTZS plotter program, and the way it calculates
> exposure
> > scale
> > >> is
> > >> >predicated on picking a maxium black value. I know that Dick
> Arentz
> > uses
> > >> 90%
> > >> >black for his work....
> > >> >
> > >> >Quoting Eric Neilsen <e.neilsen@worldnet.att.net>:
> > >> >
> > >> >> Sandy, I don't use or test a pure palladium. The smallest
> amount
> > of
> > >> platinum
> > >> >> that I add is 15% of total metal salt solution. I make my own
> > ferric
> > >> oxalate
> > >> >> and use a palladium solution that is mixed at 5 g NaPd with
> 3.5g
> > NaCl
> > >> to
> > >> >> make 40 ml. This makes a .7 M solution to match my .7 M ferric
> > >> oxalate. The
> > >> >> Platinum is a .457M solution in potassium version and .7M when
> I
> > can
> > >> get the
> > >> >> ammonium version. The molarity may be off by +/- .015 as these
> are
> > >> from
> > >> >> memory but I don't think so.
> > >> >>
> > >> >> My exposure scale for the 1.0ml FO, .15ml K Pt, and .85ml Na
> Pd,
> > is
> > >> 2.45.
> > >> >>
> > >> >> I make most of my exposures after a 10 minute dry@ 100F and a
> 30
> > >> minute
> > >> >> humidification @60% RH. I process in Potassium Oxalate at both
> > room
> > >> temp of
> > >> >> 70 and heated to 90F. The exposure test that produced the ES
> above
> > was
> > >> >> processed at 70F.
> > >> >>
> > >> >> These test were also performed with Starphire glass in the
> > contacting
> > >> >> printing frame.
> > >> >>
> > >> >>
> > >> >>
> > >> >>
> > >> >> Eric Neilsen Photography
> > >> >> 4101 Commerce Street, Suite 9
> > >> >> Dallas, TX 75226
> > >> >> 214-827-8301
> > >> >>
> > >> >>
Received on Mon Oct 3 18:10:31 2005

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