Canon i9950 prints green on photo paper
I had the same problem. Having checked other websites I came across the following which narrowed down the problem to the Photo Cyan / Photo Magenta ink tanks, and replacing the Photo Magenta one (although it was not empty) has successfully resolved the problem. Eveidently ink from the original one was not flowing and so caused the syan cast. (I experimented by subsequently removing the Cyan one which produced prints with Magenta cast)
TEXT OF POST I FOUND:-
That post is labeled "Cannon (sic) S9000 Print Head" and concerns a greenish hue error in all print quality levels OTHER THAN plain paper. In other words, all output designated as Photo Paper Pro, Glossy, High Resolution Paper, etc., results in output with enormous and unacceptable levels of green hue. All output designated as "Plain Paper" whether the output actually is on plain paper or photo paper pro, turns out well.
This problem is not unique to the S9000, as I experienced it identically with the S820 and predictably can occur in any printer with the six cartridge print head.
It is a frustrating problem because you know that the printer is physically capable of printing WITHOUT the hue (as it proves to you each time you choose a "plain paper" paper setting.)
Troubleshooting by reinstalling and updating the printer drivers, and uninstalling/reinstalling the ZoomBrowser EX, replacing the ink cartridges, and deep cleaning are all blind alleys.
A call to Canon support solved the problem for me with this simple and important revelation:
The Plain Paper setting is unique in its use of only 4 of the 6 cartridges. In the Plain Paper setting, only the black, cyan, magenta and yellow cartridges are utilized. The Photo Magenta and Photo Cyan are not utilized. In all higher resolution settings, i.e., in all other settings, all 6 cartridges are utilized.
It follows that if one's problem disappears when not using these two Photo cartridges (i.e., when printing at the Plain Paper setting), then the problem lies with these cartridges.
(In my case, I'd loaded a plain "Cyan" cartridge in the "Photo Cyan" slot during earlier trouble shooting and had forgotten to replace it with the proper Photo Cyan cartridge.)
Problems with magenta hues would admit of the same solution.
Hope that helps anyone else out there tearing out their hair trying to troubleshoot this. "