What are the issues related to Platinum versus Palladium? For example, do they have the same archival properties? In the workshop I attended, we used ferric oxalate with with a pt and pd mixture. Are there issues with using only platinum with this sensitizer? Or, is it necessary or advisable to always have some palladium included? What are other compounds that can be used for sensitizers, besides ferric oxalate? Is there something that works best, when using only platinum? For example, are there sensitisers that give a platinum print (no palladium included) a warm tone? I see from another thread that it's more difficult to turn platinum compounds into platinum metal.