Testing 18k palladium white gold

Hi everybody. I would like to know if the 18k testing acid is
suitable for testing 18k palladium white gold? What kind of reaction
should I expect from applying the acid on the touchstone? I’ve tried
to test some palladium white gold samples with 18k testing acid, but
I find it is very hard to see a noticeable reaction since the white
gold streak color is not so evident as yellow gold.

Thanks. Alfredo B. Gattai.