Send your question to
allexperts.com
Once you get into the site, look for Arts and Humanities.
Find the artist who could most likely answer your question.
They have different artist's for different types of art questions
Also send them the photo of the piece of art you have along with your question.
It may take a couple of days before they get back to you , but they will get back to you . I use them allot and they are very good at what they do and best of all they are free