NBk6

It turns out this may just be a fancy name for Asphalt, according to Cameo. How is that for branding? Notorious for cracking and often derided for its faults in painting. We have read that it has abominable drying problems and this may be due to this note from Cameo as well, "…Can slow the drying of Linseed oil…With time, asphaltum in dried oil films can result in the movement or disfigurement of the film as well as alligator cracks." We have not been very interested in researching it as a pigment for our palettes, but we were pleased to find a fascinating discussion of this pigment with linked resources over at Artiscreation.