Hi! Another nubie here! I purchased a 12a1990 cartridge by mistake for use in a Lexmark X73. I was probably selecting the new cartridge from the X63 page. Turns out the X63 uses the same regular black and color cartridge, but also has a photo color cartridge, which is the 12a1990. The X73 however, does not have a photo cartridge listed for it. So, I figured, what the heck, and installed it into my X73. It installed, but on the test page there was blue and red only. Is there any reason (other than an empty tank for the yellow not to work, for example a different configuration for the connections between the photo cartridge and printer socket. Thanks for reading and any help you can supply. Jazzman143