Every single screen I have seen here has the issue, save for one questionable photo at High ISO which most likely was masking the issue.
Your assertions in the above post are utter crap. Fringes? Really? I have never seen chromatic aberration or blue/yellow or cyan/red fringing mistaken for screen yellowing in this thread. Can you please point us to where this might be?
And since you clearly don't know what fringe entails, in most photos it accounts for only a few pixels near the edges of high contrast areas. Like a tree against an overcast sky. It has absolutely NOTHING to do with a large area of yellow across one corner of an iMac screen, and if you think so then I can't help you. And also, just because you put words in Btom's mouth and call it "fringing" doesn't mean it is the same fringing present from optical distortion. Fringe can mean "happens at the edges" and that's usually where the yellowing/bluing occurs, no?
Btom's analyses, wherein he states X% deficiency, etc. are informative assuming he has white/grey balanced the photo. STILL, depending on his methodologies, the white/grey balance doesn't even matter if he is comparing one corner to another, and noting which has more yellow or more cyan. And, despite the exact numbers of his analyses, I've never seen an actual screen on here that I think is worth keeping, just based on viewing it with my eyes, and disregarding numbers entirely.
I also enjoy how you completely make up things which I've never said. "Electronics are perfect"?? I think not. Is nearly every single consumer-level camera capable of displaying the yellowing issue without any doubt? YES. If you see the yellowing, it's NOT going to be the camera's fault, or "bad optics" fault, whatever the hell you think that means. "Bad optics" certainly aren't going to overlay a yellow tinge on the iMac screen, but not the surroundings, or any of the other pictures the person takes with their camera. As for "bad angles", I think taking the photo dead-on is a pretty good angle, and most people include several different angles. Which, BY THE WAY, the yellowing is apparent at any angle, so I don't know why you think the angle actually matters.
So let ME say it again... The only issue we have on here is that the images often do not show the problem ENOUGH, as described by many people who can see the issue with their own eyes, and who tell us it looks worse in person.
I also enjoy that you attempt to strengthen your (complete lack of an) argument by calling me "some random guy on the internet", which is funny because
so are you! What makes my argument actually valid and yours invalid is that you have absolutely no idea what you are talking about and it is very apparent to me, who has a large amount of knowledge on the subject, and can tell just by the way you speak that you are not very knowledgeable on the subject. And holding your sister's camera does not make you knowledgeable, but I'm glad that it's more expensive than mine since you think that strengthens your argument.
In addition to my years of knowledge on the subject, I have also read nearly every single camera review that dpreview.com has ever posted, which go into detail about distortion, aberration, fringing, high ISO performance, chroma noise, luminance noise, etc. for every single camera, and never have I seen a uniformity problem in a camera sensor that could mimic screen yellowing.
Vignetting? Take the picture from far enough away. Most do. Does it affect color cast? NO.
Fringe? Does it affect screen color cast? NO.
Aberration? NO
Barrel/Pincushion distortion? NO
Viewing angle? Yellowing is present at all angles.
Ambient Light? Makes no difference.
And I could go on and on and on.
Seriously, all you have to do is make sure some part of the screen is white/grey balanced,
and the color uniformity issues will become apparent.
Probably the only valid point you've had thus far is that if the person can't see it, they should be happy with their iMac. Frankly, I think these people must be blind with some of the uploads I have seen accompanied with "I don't see the issue", but that's great for them then. That doesn't mean they shouldn't come on here and ask if their iMac has it. What about resale value? They may not successfully resell an iMac with a crappy screen. What if they take up design or some such hobby, and it affects their work because they unknowingly compensate for the yellow cast in some areas?
I think what Btom does here is a good service, and if you have a problem with it you should stop posting in this thread. "Fatally flawed"... Sheesh. You could at least be less dramatic about it.
), using a longer focal length and being well centered above middle of the screen. You may want to play with settings a little bit to avoid visible moire pattern and maybe screen refresh effects. 
