Sorry to drift away from the topic.....
Not sure if I understand what you mean correctly, but, is it something like this? (Diamine China Blue with Brause No.361 dip pen)
Yes! That's exactly what I'm talking about. (For everyone else, you can especially see it in the capital T in "Talks" in the upper righthand corner, and in the word "Some" at the bottom left corner of the image; it's more than just shading, because it really is mostly along the edges.
Anyone else out there experience this with inks? Anyone know how to describe it better?
Ruth Morrisson aka inkstainedruth