Nearly all Dye Sub printer use a roll of photo paper to print on. The width of this paper dictates the maximum width of print. Printers that use a 6 inch roll of media are the most popular and are usually able to print from 6×4 up to 6×9 depending on the type of media used.
Typical print speeds for these printers are around 9 seconds for a 6×4 print and under 30 seconds for a 6×8 or 6×9 print.
Some of the newer Mitsubishi photo printers like the Mitsubishi CP-K60DW-S, CP-D80DW and the CP-D90DW have something called rollback technology which means you can print a 6×4 and a 6×8 from the same media roll. This means less wastage and less money as you don’t have to keep buying different media sizes for your printer.