I use an Epson R2400 and print on both matte and semi-gloss papers, so of course have to switch between the photo black and matte black inks. My method of purging the ink prior to printing on the new paper type is to print a file I have made that is pure black and covers about a quarter of a letter-sized sheet of paper. I work from the assumption that this empties out the print head plenty enough to be ready for a print on the new paper type. Can anyone find fault in this approach? I read about people using Epson 3800 printers spending a fortune purging their blacks for a swap, and I wonder why it is that they aren't using a similar technique. Is it because the tanks are separate from the heads, or that the firmware in the machine won't let them do anything BUT do an all-cartridges purge when they put in the new cartridge. Or am I fooling myself, and my printer is actually doing an all-cartridges purge when I swap tanks, and I'm just not paying close enough attention?