I would agree that the p/p ratio in combination with developers will
vary the color. Palladium is much smoother in the way it lays down.
Platinum is much rougher in the way it lays down. ( much more platinum
in suspension following development) I think clearing stain of
(platinum in precipate) can occur with higher proportions of platinum.
Platinum is more contrasty. It will deepen your shadows. It will add
a lot of contrast if you are working in straight palladium. it only
takes a few drops. ie 8/4, 9/3, 10/2 palladium to platinum. Less
than two drops doesnt give the fuller platinum impact.
Gary Auerbach
http://www.ibs-net.com/platinum.htm platinum photography
http://www.flash.net/~internut pistachio ranch