Oh boy, having never framed a pastel before and now reading through some posts about it I feel like this may be a tough one! I make custom frames and have been asked to make one for a pastel artist. Basically it's similar to a floater style frame with glass. The pastel (7" x 9") needs to be mounted on a raised box, there will be 4" of space all around it so it's inside of what could be called a shadow box which will have glass over it. My concern/question is how to I attach the pastel to that raised box? The artist wants the artwork to basically appear to be floating inside of the shadow box. Would making some sort of hinge like is done with water colors be the solution? I'm afraid that eventually there would be some gaping but if the perimeter of the art work was taped to the panel that wouldn't allow for any expansion -- any thoughts?