I can't speak for the bulk of CIS resellers but if I remember correctly the photo black and Magenta inks were different between the two types of cartridge but in truth you don't want to be purchasing a CIS without the correct ink.paragon said:I'm finding that some of the bulk ink sellers aren't carrying ink for the MP 500 CLI 5 & 8. Is it that much different that the in for the BCI 3e and 6 carts? I just don't want to damage any jets, etc.