Some thoughts:
I yesterday made again a pt/pd print after 3 years abstinence from the process. I used a sensitizer of sodium palladium chloride an a little bit of potassium platinum chloride, ammonium ferric oxalate. Turned out just as expected, colour quite neutral, because I kept the paper quite humid.
I used to print a lot in this way (sodium pl ch with AFO), with or without pt, with or without other ingredients. Keep the humidity a bit less, and you get a printout in beautiful chocolate brown, exposure time goes up.
Anyone tried this? Why using lithium palladium chloride at all?
I also have a question for users of Arches Platine paper: is it currently working properly, or are there bad batches around? I ask because I am thinking of getting some, and as this is, due to my current residence, a major effort for me, I better make sure that it is likely to work.