Brown Ink Hue Used by Old Masters for Sketching

This page is the CodyCross answer for the clue below from Professions, Group 1530, Puzzle 5 (Acupuncturist).

Question is: Brown Ink Hue Used by Old Masters for Sketching

and the answer is: BISTRE

Word Meaning:

BISTRE — A brown pigment made from soot, especially from beech wood.

Definitions from Wiktionary.