I am unsure what resolution such printers can offer. In the cases of, for example, a "30cm x 40cm" or a "50cm x 70cm" print, what would be the max size (number of pixels) of the graphic file in order to make full use of the Printer's capabilities and that of the paper it is to be printed onto?

Or perhaps, if it is an easier question; what DPI can these printers print at?