RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/03/05-03:05:29 PM Z
Message-id: <20051003210531.ABB3F76F19@spamf4.usask.ca>

Only 12 ? wow

 

Eric Neilsen Photography

4101 Commerce Street

Suite 9

Dallas, TX 75226

http://e.neilsen.home.att.net

http://ericneilsenphotography.com

 

  _____

From: Sandy King [mailto:sanking@clemson.edu]
Sent: Monday, October 03, 2005 4:00 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Best CI for process

 

Mark,

 

When I evaluate a step wedge print made from a continuous tone step wedge I
count the steps from the first density over pure paper white to the first
shadow step that merges with the next one. Using the pure palladium mix I
described earlier I usually get about 12 steps, which works out to a
exposure scale of 1.80.

 

Sandy

 

 

 

 

 

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Hi Eric,

Just for reference, how do you figure your exposure scale? I know this
sounds like a dumb question, but I have seen it defined differently by
different people. Do you include the first paper white step also?

Sandy, could you also respond to this question?

Thanks,
Best Wishes,
Mark Nelson
Purchase the eBook & PDN System for Your Own Custom Digital Negative
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In a message dated 10/3/05 1:03:42 PM, e.neilsen@worldnet.att.net writes:

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.

 
Received on Mon Oct 3 15:07:11 2005

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