This may or may not be of value, depending if it has any affect with other people's iMacs. But I was VERY startled by it... A neighbor has a new iMac, 27". She wanted some help tonight with basic things like setting up preferences and stuff. Anyway... I couldn't help but notice yellow tinge. And more strong than the previously-replaced model of my own. I didn't mention it to her for fear of spoiling her excitement. What proved interesting however was this... We went through the desktop images to see which she liked and we came to the Apple BLACK AND WHITE images (seascapes etc) and then SPECIFICALLY the one with the jetty receding into the water. Please select THAT image on your own desktop for a few moments.. ANY WHITE WINDOW OPENED ON THAT DESKTOP BACKGROUND (either totally white window or with color images within it) WAS TOTALLY FREE OF EVEN MINIMAL YELLOWING. The gray bars on the windows show absolutely NO WARMING or change of tone as they are moved down or across the screen. Totally even and without variation. I was quite amazed actually. The difference was DRAMATIC. Changing back to any color desktop image showed yellowing again, in any window as it was moved up and down or side to side on the screen. I'd be interested to know if this is happening with other people's iMacs. If it is, it would be very worthwhile taking a look. I don't see why it should be limited to the neighbor's computer I was looking at. Strangely, the same didn't happen when using a FLAT gray color desktop – just the photographic one. Comments?