I'm experimenting with using some of the NP pigments for etching inks. Some are mixing up quite nicely and I'm anxious to try them on my plates/prints.
Some I've found are extremely sticky, maybe more so than I want, making them very hard to wipe on the plate. Two that I found this with so far are the Vincenza White and Green Raw Umber.
I'm wondering why the viscosity of these is so different than many of the other pigments? My uneducated guess is that maybe they contain more clay-like material which accounts for their stickiness? Again, that's just a guess.
Any thoughts on why this might be are welcome? Or what I might do to address this?