Help with name of artist of miniature portrait

This is 1 of 4 paintings I bought today at a local thrift store. It is a painting, not a print.
Can anyone make out or recognize the artist's name?
Thank you!

 

These are little decorative paintings. (The backing is one giveaway.) The name of the artist is not of import. Could be a copy of a Tudor-era portrait although looks a bit of a fantasy.

Debora

 

nice painting.......

 

I always thought frames were bone. Meant to mimic ivory.

Debora

 

I opened back - was thinking of putting it in a different frame - and when I saw the medium it was painted on I thought 'celluloid' but you can see the grain (bone grain is straight & ivory grain is like tic tac toe, right?) in 2nd photo below, so it is painted on bone right?.
I don't know if I chipped bottom left corner or it was like that; does it hurt it's value? (it isn't noticeable when back in frame - last 2 photos)
As always I am grateful for your help & information

 

Sheesh - I was looking at komakwa's link when I finally(!) saw it was bone frame not that it was painted on bone! Man I feel like an idiot sometimes!
So if I may ask - is it celluloid or plastic or bone or something else that it's painted on?

 

Can anyone tell me what the portrait was painted on?

 

I'd say a thin layer of bone.....but could it be china???
I can't tell from here !!!

( oh...& not my link....or my name ! )

 

ive had a couple of these types before, i dont think they are 100% hand painted

only the signature and highlighted brush strokes are painted

underneath they were some sort of print on celluloid

it does look that sort of thing as well

 

These aren't terribly old. I'd be surprised if painted on celluloid. I'd think it was just regular ol' 20th century plastic. The portrait really doesn't have any value, chipped or not. Have fun with it.

Debora