Do you recommend TIFF or PNG?
We recommend the customer uses TIFF file format for printing over PNG file format. Both are lossless file formats but TIFF files support more color spaces and will offer a greater color depth over PNG format. This is why the TIFF format is more widely used for printing and PNG for graphics on the web.
We recommend the use of Adobe 1998 RGB color profile as it has the largest usable color gamut but we also accept CMYK profiles as well. Especially if the customer is used to printing with CMYK. For reference and soft proofing, our color Xerox Iridesse printers rip uses CMYK GRACoL2013.
Our complete file guidelines are here.