The Canon ink has an extra black.....it's like Fulfilling the spot as the mediator of the colors and black cartridges. So your color won't use your black and vise versa. In-fact all Canon genuine 221 ink tanks will always be dye-based which mix well with glossy photo paper. While the 19 mm 220 (Pigment) tank is strictly "text" black. The days of robbed black ink cartridges is over. (Hopefully),
So I was trying to explain it at a customer level, So I simply said the extra black is like you got half & half for your coffee. and started to notice how much Drinking Milk was left for your kix cereal because of that so called "mediator"; If you would?
By the way HP has copied Canon, check out the 564 bundle. they introduce the second black (Photo Black) in premium models only.
I also realize stores like office max and Staples have reward programs where you get money back for cartridges, Simple math tells us if you have more quantity you'll get more reward. We'll ink is also moving away from tricolors. Which means you get away from a 2 cartridge set; you now have individual cartridges. hence more quantity & rewards to discount future ink purchases.
