I've given up on the Pigma pens because they dry out so quickly, in my hands. Nothing but graphite seems to be acceptable on MK papers. So I've gone the inkjet route, meaning my signature - and sometimes my handwritten captions - are printed along with the image, at inkjet time. PNG files, created with a Wacom tablet in PS, are the source of the handwritten content. LR assembles the composite in the Print module. This is fine for my purposes, and I don't mean to suggest this method to all artists.