After buying an Epson R1800 about 18 months ago I noticed that a low resolution jpeg off the web looked pretty good when printed without any upressing. I tried an experiment, printing an 8X10 from a full size crop from a 5D file at 72 PPI and comparing against the same crop uprezzed to 240 PPI using bicubic smoother followed by some sharpening. I could see very little difference between the two prints but the print that was sent to printer without uprezzing had the edge where there were any differences to be seen. So, needless to say, I no longer bother to do any uprezzing or down rezzing when printing as the Epson driver does a good job of handling it. Furthermore the old saw, which may have been true at one time, about setting the ppi to some multiple of the printer resolution doesn't seem to hold anymore for the newer Epson printers.