[ROL]

The very safest way to package unmounted artwork is in wrapped in archival paper in an oversized tube mailer with foam rolled up in the centre and stiff card around the outside.

I wouldn't recommend rolling up fiber based prints unmounted or otherwise! And if we're talking fine art prints, fiber is what we're talking about, by my reckoning.

But here is how I do singles, most inexpensively up to 16X20 (24X30 matted). I only ship matted fiber prints. Too bad if they want them unmatted – I sign on the mat (excepting special institutional purchases). I place archival tissue between the matted print and its window mat. Then, 1-ply archival barrier paper over the top of the window mat. I place the entire sandwich in clear polypro bags then cut cardboard oversize of the mat at least 1 inch around in 2 opposing directions of "grain" construction so that 2 layers cover both top and bottom. Then tape it up, paying attention to covering the open sides completely. The whole package sandwich consisting of 4-ply matted print, 8-ply window mat, and 4 cardboard layers is very stiff and unyielding. For multiple prints I use AirFloat StrongBoxes (expensive).