Update docs/assignments/week04.md

docs/assignments/week04.md

@@ -232,8 +232,10 @@ Fabrics names (fr/eng:)
 Piece of fabric
 
 ## Inks 
+
 And with Diane we made some inks, was a lot of fun.
-Using red cabbage, iron liquid.
+Using red cabbage as a base and changing its color with iron, alum and sodium bicarbonate. 
+To make the base red cabbage ink, we boil it for some time, filter it and its ready. Would be nice to make a full aquarelle pack this way. 
 
 ![](../images/week4/ink.jpg)