Lex Z2420 Conserving ink?

[Marle79]

So i recently chatted with the Lexmark techs and found out (according to them) that there is no way for me to print black and white photos using the black ink cartridge only. They claim no matter what, the printer has to use both cartridges, even though I know of many other printers who only you to mainly use the black ink, if you so chose. Anyways, I am finding that when i select "best quality" and print like a 5x7 photo, I am losing almost 1/4th of my color cartridge. All of that for a measly 5x7 photo? Does anyone have any advice? Am I possibly not setting the appropriate options or did i receive a super crappy printer when it comes to photo printing. I mean I realize it's kind of lower quality, but never had I imagined I'd be running through color ink so quickly. Any suggestions would be helpful. Thanks so much guys!