N_Cook wrote:

More out of interest what went wrong than necessity as only used for poster
use. Epson Stylus 915, if relevant.
Lack of Red and excess of Yellow
A perfectly adequate get-around is +30 percent of Red and 30 percent less
each of Green and Blue in the graphics package. It all started with a postal
packing foam "doughnut" dropping unnoticed into
the paper entry slot and numerous paper jams before finding the culprit. The
ink-jet cartridges are re-set , re-used/ redilled multiple times and
refilled and reset since this foam business. Built-in "cleaning" and the
other maintainence routine has made no difference. The colour imbalance is
stable and invariant over perhaps 30 sheets and 4 separated sessions.

At a guess, there's some crud on top of a colour-calibration photodiode
somewhere inside.

Cheers

Phil Hobbs