It was mentioned in this thread, "Traditional sap green and alizarin pigments have reportedly done extremely poorly, some accounts indicating substantial fading in only 2 to 4 years."
A couple of years ago I did a test of alizarin crimson by painting three squares of 1) pure alizarin, 2) one middle value (mixed with white), and 3) one light value, on two separate strips of canvas. I put one in a drawer and one on a window sill with north light. There was no direct sunlight. After only six months the one on the window sill was two to three values lighter, the pure one being the least changed. The one in the drawer was unchanged.
I would expect the same results with sap green.
Steve Moppert
|