Re: Is Na2 that sensitive?

From: Clay ^lt;[email protected]>
Date: 11/29/05-05:33:01 PM Z
Message-id: <D32F6957-B227-4DC1-93C7-6D5B78342483@wt.net>

This is one heck of a lot of Na2 for these volumes. I am using 1 drop
of 2.5% Na2 in the same sensitizer volumes for my digineg work. I
would cut this stuff 1:7 (2.5%) and just use a drop or two of that
strength.

On Nov 29, 2005, at 11:00 AM, Raven Weiss wrote:

> Hello,
>
> I posted this (below) on Mark Nelson's PDN Group, but I'm hoping to
> get a wider response here at ALT-Photo.
>
> Sincerely,
> Mike
> www.ExposeTheShadows.com
>
> Raven Weiss <ravenweiss@yahoo.com> wrote:
> To: PDNPrint@yahoogroups.com
> From: Raven Weiss <ravenweiss@yahoo.com>
> Date: Tue, 29 Nov 2005 08:25:45 -0800 (PST)
> Subject: Re: [PDNPrint] Is Na2 that sensitive?
>
> Hello Mark,
>
> Thanks for your quick response (below).
>
> Looks like you are using a serial dilution method, which makes
> sense if Na2 concentrations need to be that precise.
> Unfortunately, I don't have a pipette, just an eyedropper. In your
> experience, will it be sufficien t for me to serial dilute as you
> suggest but use an eyedropper if I'm using enough Na2 that equates
> to a concentration in the middle of Dick Arentz's chart?
>
> Also, if I humidify my paper prior to exposure, will I drive this
> (film speed of the paper) towards repeatability? Or, will I just
> introduce another variable? Specifically, the relative humidity is
> around 10-15%. Does this variability cause a change in paper speed
> - and, does humidifying the paper to anything above 50% keep the
> paper speed constant?
>
> I hope I'm making my question clear.
>
> Sincerely,
> Mike
> www.ExposeTheShadows.com
>
>
>
> Ender100@aol.com wrote:
> Mike,
>
> Na2 is very sensitive.... I am not sure how you are measuring, but
> it is
> possible that your problem could relate to that. Have you seen
> Dick Arentz's
> chart for Na2? It is availab le on his website.
>
> I dilute the Na2 by cutting it with equal parts of distilled
> water... then I
> repeat to get 20%, 10%, 5%, 2.5% & 1.25%. I do this with a pipette.
>
> Also, humidity can vary speed... make sure your humidity and drying
> times are
> constant.
>
> Best Wishes,
> Mark Nelson
>
>
>
>
> In a message dated 11/29/05 1:07:37 AM, ravenweiss@yahoo.com writes:
>
>
> > Hello Folks,
> >
> > I've used the PDN system with success late last year to produce
> Pd-toned
> > Kallitypes.
> >
> > Now, I've been trying to create an adjustment curve for
> Palladium using
> > Na2 contrast agent. Finding the correct exposure time was easy.
> However,
> > getting the correct color density choice (choosing the first
> "paper white"
> > square) has been very difficult. I'm getting everything between
> B=30 and B=70
> > (with R=0, G=255) with th e same (I think) level of Na2.
> >
> > Specifically, I'm using 1.7mL of FO and 1.5mL of Pd sol'n#3 and
> 3 drops of
> > 20% Na2. All chemicals are relatively new & clean - from Bostick &
> > Sullivan.
> >
> > The drift in color density choice is causing wide variations in
> the
> > 101-step tonal palette, as you can imagine.
> >
> > I'm thinking of diluting the Na2 by 10 fold and using 10X of
> this dilute
> > solution - hoping that the variability will average-out and give me
> > reproduceable results. Any hints on how else to proceed?
> >
> > Sincerely,
> > Mike
> > www.ExposeTheShadows.com
> >
> >
>
>
>
>
>
> Mark Nelson
> Precision Digital Negatives
>
>
> [Non-text portions of this message have been removed]
>
>
>
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Received on Tue Nov 29 17:34:23 2005

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