RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/03/05-04:08:49 PM Z
Message-id: <20051003220853.48ADE76F0A@spamf4.usask.ca>

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 16:09:19 2005

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