Best way to ship a largeish print?

A customer recently ordered a 16 X 20 print. What is the best way to ship it? Rolled in a tube? Or flat, anchored & sandwiched between two sheets of cardboard? Other methods? I've never shipped one this big so need a little help. Thanks.

Rolled in a tube will always work, and it's easy; however, I generally try to ship anything 16x20 or smaller in a flat box or sandwiched between cardboard. The tube is generally cheaper though.

I'm with Bill on this approach. Although, I find anything up to 16 inch total I ship flat, otherwise, all in tubes. I find the tubes much easier and seemingly stronger for protection from most punctures too.

If you go with a tube, try and find one at least 4" in diameter, which isn't always easy, most places sell 3" tubes. I find those a little tight to roll. You can buy 4" tubes online but the problem is minimum order quantity, you usually have to buy several at once. I guess it also depends on paper stock... I can roll some of the softer fine art papers down to 3" but if someone orders the very thick Canon Platinum Pro high gloss paper, that's a bit hard to roll down to 3".

A related question: What do people use to protect the face of the print when rolling it?

I recently shipped a 20x24 metal paper print in a 4" tube and added paper towels on the print side to protect from scratches, ets. The frame shop found the print damaged from shipment. Reprinted and dry mounted and sandwiched print again between several layers of cardboard and all was ok.