NZE,
Right now our most interesting tests involve using sodium tungstate as
an additive to the basic Ziatype formula, (warms the color and lowers
contrast) and using different (from ammonium) ferric salts in the ferric
oxalate sensitizer solutions. Those are still being tested. We'll have
an enormous Ziatype section in our book on platinum printing, which we
hope to have out in a few months. Testing furiously at this
point--formulas and all data will be published once we've tested
sufficiently.---Carl