I spent the Weekend at my parents to check up with my hibernating plants (a lot of which seem to have died), meet up with a bunch of friends (all alive and healthy) and pick up a bag of apple-tree-bark from an apple-tree-branch my father saw of a couple of weeks ago.
The book says there is a yellow colour hidden in somewere therein.
And I intend to go looking for it!
The next step is to cook the bark with an alum-solution.
Wish me luck.