Do you know about the tapestry painting technique called 'succo d'erbe'?

Question

We bought an antique painted tapestry and the woman we bought it from said that the method of painting was called 'succo d'erbe,' or grass juice. Can you help me out?

Answer 1

It is naturally colored. Older tapestries tend to fade and only the blue and some purplish red stays.

That's about all I can remember about it.