I'll try to get a couple of pictures by tomorrow. Have to find my digital camera.

The width of each holder is 12 7/8" wide and 16" long (or deep) from the bottom of the holder to the locating notch at the top. Of course the holder extends above that but those are the two major dimensions on mine. The thickness is just shy of an inch on two of them and third is about 1 1/4 inches. On the third and thicker film holder the backing piece is the same distance from the surface of the holder itself if you understand what I mean. I don't remember what the depth to where the film rests is right now. I would measure but all my film holders are presently loaded with film. The only 11x14 film boxes I have right now haven't been opened yet so I have no place to store the film when I pull it out for measuring. I may have an open box of printing paper I can store the film in but I haven't found one yet.

This should give you a start though.