Search:

Cut the ferric with water,experiment with it,the weaker the solution and exposure time, the lighter the color.

Your not wrong Jim,Never have been:) where the spine sits on the stone,really makes not a hill of beans unless you sell blades on the bay and such,you can pick up an 1/8 the american way,right or...

As I was told by Heribert Wacker himself.The german way to measure a blade is the center of the spine to blade edge.
He said the american way is wrong (top of spine to edge).