RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/03/05-03:00:42 PM Z
Message-id: <20051003210044.07BD476E22@spamf4.usask.ca>

It is derived by looking at the 21 step scale, taking away the absolute dmax
reading, taking away the absolute dmin reading, and seeing what's left. I
interpret the useful dmax in a more liberal way than some might. At 8
minutes of exposure I produce a full scale printing of a 21 step scale with
the chemistry and procedure listed in previous post.

I think that a major problem with setting standards, within a system of
platinum/palladium printing, is that assumptions are made with regards to a
whole pool of complex interactions.

I have not mapped out a complete set of exposure scales for each variation
in my pool of variables. I have taken my 21 steps scales and printed them
with various batches of FO; B&S, Artcraft, Formulary, self made, Jeffrey's,
and compared speed, printout, and color. I have also taken them and printed
them with variations ratio of PT to PD.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 
> -----Original Message-----
> From: wcharmon@wt.net [mailto:wcharmon@wt.net]
> Sent: Monday, October 03, 2005 1:09 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Best CI for process
>
> 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 15:01:05 2005

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