"The controversy with Study by Candlelight is whether it’s a real painting by Vincent Van Gogh or a forgery, as claimed by his nephew. It looks like a self-portrait of Van Gogh, but the lower third of the painting is unfinished and contains a strange Japanese kabuki character. The character was added in ink, not paint. There’s also a question of why French accent marks don’t appear on the inscription “Etude..." http://listverse.com/2015/03/28/10-unsolved-mysteries-that-confound-the-art-world/