THIS IS A LINK TO SIGNATURE
THIS IS A LINK FOR CLOSE UP
THIS IS A LINK TO SLATE BACK


I bought this at an estate sale (I was lucky (I think), two ladies pooling their money were only able to buy one of the two. I paid $175 for it.
I've been told that the signature looks real (has '99 with it) and that Mucha used all kinds of materials - he didn't just do prints & paint.
This is on some kind of slate and I want to know if it's real - I've only known Mucha for his Art Deco prints and the cover on JOB rolling papers (from a youth a long time ago).
Any help would be greatly & sincerely appreciated.
Thanks. editor@itsallinthejourney.com