Re: Best CI for process

Mark,

Yes, it is possible to set the exposure scale to whatever you want,
within limits, especially if you use the Na2 method of contrast
control. By adjusting the amount of Na2 it is possible to set the ES
from as much as 1.9 to as low as 0.8.

However, what I choose to do is set the exposure scale of straight
palladium very close to the upper limit, which for me is around 1.85.
This can vary a bit of course based on choice of paper. Then I
develop all of my negatives to this range, whether they be in camera
negatives or digital negatives, and I don't have to worry about
adding any Na2.

I usually add just a tiny bit (about 1 ml per liter of developer of a
5% potassium dichromate solution) to the developer for better
clearing. This small amount does not affect ES very much, if at all,
but my papers seem to clear better with it.

Your question does make the point, that we might should be more
specific when discussing these issues. To that end I will mention
that my normal mix is equal parts of a 25% solution of ferric oxalate
and 20% palladium chloride. I develop in potassium oxalate, at room
temperature.

Sandy

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>
>Sandy,
>
>Doesn't it depend on what contrast agent you use, if any? So, you
>can choose whatever you want? Or are you speaking of a contrast mix
>of Palladium designed for an in camera negative of a specific
>Exposure Scale or CI?
>
>Just trying to follow the conversation hehehehe
>
>
>Best Wishes,
>Mark Nelson
>Purchase the eBook & PDN System for Your Own Custom Digital Negative
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>In a message dated 10/2/05 11:22:58 PM, sanking@clemson.edu writes:
>
>>Eric,
>>
>>First and foremost I derived it from my own work.
>>
>>The scale is also very similar to what Dick Arentz reports.
>>
>>What is your exposure scale for pure pallaidum?
>>
>>Sandy
Received on Mon Oct 3 07:39:38 2005