[pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax 100
- From: Tony Wingo <akw@xxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 9 May 2007 12:50:48 -0700
At 1:31 PM -0700 5/9/07, Peter De Smidt wrote:
mail1 wrote:
Jim, I am interested as to why you think densitometers are problematic.
I'm not Jim, but I'll give it a go anyway. The trouble with
densitometer and the various film stains is that the densitometer
and photographic paper do not respond to the light transmitted
through the stain in the same way, mainly to differences in spectral
response. I do have some experience with this. In my opinion, the
best way to figure this out is the following. Get a Stouffer 4x5
stepwedge. Read all of the steps with a densitometer. Make a
contact print on your paper. Use and exposure such that you have
pure black steps and white steps on the contact sheet. Now if you
want to get fancy, you can use a reflection densitometer to read the
patches. Anyway, now make a contact exposure with the stepwedge on
your film. Develop in the staining developer. Make a contact print
with the resulting negative. Compare the two contact strips to
evaluate contrast. Read the stained negative with a densitometer,
and based on the differences between the stained negative and the
step wedge, come up with a function that expresses the stain
density's effect on your printing paper. Personally, I'd stop at
the comparing contact sheet stage, but to each their own.
There are several articles up on unblinkingeye that touch on this
issue. In particular this one
<http://unblinkingeye.com/Articles/Densi/densi.html>, though it is
primarily concerned with platinum printing.
--
-tony
San Leandro, CA
http://www.shapesandshadows.com
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