bistre
/ˈbɪstri/ or /ˈbɪstre/Definitions
1. noun
a dark brown or reddish-brown powder made from the sap of birch trees, used in drawing and painting
“The artist mixed bistre with linseed oil to create a rich, dark paint.”
2. verb
to treat or dye something with bistre
“The painter bistre-finished the wooden furniture to give it a warm, antique color.”