All papers require different treatment which may include different amounts
of sensitizer, different approahces to coating and drying, etc. so its no
surprise that your results with Platinotype were different from those with
Bienfang. It will just take some experimentation to figure out what exactly
needs to change.
I had read long ago in Palladio's literature some stuff about Hydrogen
Peroxide's aging properties, etc. Sincer their pre-coated paper comes in
one "grade" the only control one has over changing contrast is through
developers. One technique they use often is to add Hydrogen Peroxide as a
restrainer/contrast control agent. They claimed that after extended use,
the loosely bound molecules of Hydrogen Peroxide would make it turn into
water to which a chemist friend of mine replied "Phoeey" (he actually
wasn't so polite). My friend said that one need not worry about aging and
the oxidation of Hydrogen Peroxide given the weakness of the solution and
even suggested it might become stronger over time, though his explanations
went over the head of me who failed high school chemistry (and it sounds
like english, too). Perhaps someone else on the list can provide a
chemist's explanation in lay terms.
*************************************************************************
WILLIAM LAVEN PHOTOGRAPHY
Offering Platinum/Palladium printing services and workshops and tutorials
in Pt/Pd printing and other areas of photography (Zone System, etc.)
1931 23rd Street, San Francisco, CA, 94107
415-647-9432 (voice) 415-647-9438 (fax)
wmlaven@platinotype.com
www.platinotype.com
*************************************************************************