I would say, “This is a fake”, and the art gallery owner would say, “Well, yes, of course. I mean you can see it’s a fake, because Modigliani would never have drawn the line of the arm parallel to the line of the dress that way. 
And the background is very badly done, and the signature isn’t right.”

In the next gallery, I would show them this Modigliani in the catalog and say, “That’s a genuine Modigliani.” And they would look at…