Lots of dialogue regarding the use of "B" solution in p/p printing. Terry
who
claims it severly degrades the image and others who say small amount
will work well.
My experience, which has been originally to use the B solution for contrast
boost,
tried the platinum metal contrast method, and am now back to using the
Chlorate.
About eight months to a year ago, this discussion came around. At that
time
I decided to switch to Terrys method, which is to use Platinum as the
contrast
boost. Increasing platinum proportion to palladium will give about a one
level
change in contrast. By one level, I mean if 12 A =
3Platinum/9palladium
11A + 1B
= 3platinum/9palladium
10A + 2B
=3platinum/9palladium
There are three levels here. By shifting to 9 platinum and 3 palladium I
gained
one level in contrast. If the negative is not in the 10 + 2 region,
going to this
method will not be enough contrast additive. Going more platinum than that
ratio brought on additional coating problems relating to platinum's more
tempermental qualities.
I am now back to using the chlorate material.My negatives are usually in
the
12A to 11 + 1 range. Using Cranes platinotype paper, I can one coat
the paper using a glass rod, and get very good dmax. No sizing.I do not
see any
degradation of image using a small amount of Chlorate on the images.
Different
papers exhibit different reactions. Keith Schrieber of the Center for
Creative
Photography here in Tucson could comment on different paper reactions.
The cost of Platinum compared to Palladium is significant enough that when
printing many prints, the chlorate method of contrast control for me
works best.
The ease of working with a palladium based mixture of p/p keeps me
at a 3:1 palladium to platinum mixture.
Appreciate additional dialogue on this.
Gary
Gary Auerbach Platinum Photography
http://www.azstarnet.com/platinum
cycloid fathom gallery show
http://www.cycloid-fathom.com/gallery/html/auer.gst/auer.htm