my prints were mounted and matted to 16x20. I was told that it does not matter if they were mounted and matted and that the images are the important things. Richard Newman from Calumet was the source of the information. I went to a DYI store and bought some Masonite hardboard that is about 1/8 of an inch thick and was about 2 foot x 4 foot. Cheap less than 2 dollars. I cut the board to 20x24 and sandwiched the prints between the two boards and taped the 4 sides with everthing inside with black gaffers tape. My feeling was that the Masonite is about as light as anything and tough enough to survive the US Postal Service handling. It cost approx. $12 to ship from Tx to Ca. YMMV
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