Kakos stromithicarum

Kakos stromithicarum is the primary ingredient in creating pigment. While it's one of the only material components, it's properly infused with Spectre ichor in order to create pigment.

Background information
The name "Kakos stromithicarum" is, of course, a fictional plant. "Kakos" is Greek and means "bad, evil" as in the word "cacophony." "Strom" is Old High German for "stream" (and the second component in "maelstrom").