Though a very inaccurate comparison, these are the "Mile High" equivalents for animation cels. Courvoisier was a gallery in SF which contracted with Disney early on. The backgrounds were often made of wood, and the mats were specially cut for each cel. Interestingly, the cels themselves were often cut to the figure, so there was "restoration" and "trimming" at the point of sale! There is always a WDP logo and most often a handwritten title on the mat. Recently, a company has revived the Courvoisier label and is offering modern reproductions. That company is out of Westlake Village CA.