Yellow tinge from bottom to top of the screen, 27" iMac

Got my 27 inch iMac yesterday and yes it has the yellow tinge and some drips of something behind the glass. Looks like someone sprinkled about ten drops of syrup on the glass. Called Apple Care and they scheduled me with my store for replacing the display, not the entire machine, which makes me hopeful that they have replacement displays that work. Otherwise the machine is amazing and I can't wait to use it.

For you that are interested in learning about LCD screens look at this video course by 3M:

http://solutions.3m.com/wps/portal/3M/en_US/Vikuiti1/BrandProducts/secondary/opt ics101/

It explains IPS and the LED backlight in very clear terms

As you can see by my equipment I need an upgrade but have been waiting and following the outcomes talked about here.

oldfred76 wrote:
For you that are interested in learning about LCD screens look at this video course by 3M:

http://solutions.3m.com/wps/portal/3M/en_US/Vikuiti1/BrandProducts/secondary/opt ics101/

It explains IPS and the LED backlight in very clear terms

As you can see by my equipment I need an upgrade but have been waiting and following the outcomes talked about here.

Thank you, the video looks very interesting.
I'll have a look at it this WE.
Cheers!

I have been following this discussion since my first Imac week 48 back in December 09.
And to make a very long story short, picked up a week 10 27" i7 replacement from my apple store today and was so happy to see no yellow tinge. However, I did notice a horizontal band towards the bottom of the screen. This band is slightly visible with white but become more pronounced with a solid color. I've seen a few post of others who are having this issue too.

The bottom line is, it's too bad apple can't get this 100% right after all the problems its customers have been put through. And as thrilled as I am to finally have a uniform white screen without yellow blotches (it can be done), it's amazing to me that I still have to make a compromise with the screen
of an otherwise incredible machine.

I have the same issue but it doesn't bothers me it shows only when there is a full screen color like the apple logo startup, but thats about it, and its like some sort of in burn screen but that came from factory most LCD monitors have this problem people just don't notice it at first I notice it at first, but I am fine with it.

Tom Alexander wrote:
it's amazing to me that I still have to make a compromise with the screen
of an otherwise incredible machine.

Switch900 wrote:
I have the same issue but it doesn't bothers me it shows only when there is a full screen ...

Hi Tom and Switch900,

My state of mind today :
As you can see I registered on Apple Discussions Dec 3, 2009 regarding the flickering issue. It helped a lot and it is solved now.
Then I landed in this 'Yellow tinge' thread and began testing and examining my screen. Badly It wasn't perfect, though I didn't notice it before. 🙂
As I am an engineer, I dug the question (the so-called state of the art). Now I know *my screen* is probably 97% as good as it can be. Period.
Possibly some have better and some have worst.
I have a 3 year warranty .... I'm now going to enjoy my new computer and as you both know : it's a computing beast!

The beat option you have done is to enjoy your machine because if you just worry all the time that your machine is not perfect, then you would not enjoy the technology you have and order for your enjoyment.

It looks like things are really slowing down here. I suspect below the yellow tinge issue has either exhausted us all or it has diminished in importance. After many months of waiting I am about to place an order online for a 27" iMac. Wish me luck!

Unfortunately, this horizontal shadow at the bottom of the screen continues to be an issue. I have seen it on all 3 displays that I've had on my desk. The third i7 27" iMac I currently have on my desk is the worst. I do not think Apple is willing, or perhaps able to remedy this flaw. It really bugs me having spent nearly $4,000 for a flawed product, but I am resigned to the fact that it will not live up to the moniker "ultimate display". No matter how many times they replace it, there will likely be a flaw inherent in the design. There are no perfect displays. I have seen the horizontal shadow on every machine in the local Apple Store.

There is still non-uniform white balance across the screen as well. After viewing the video link to the 3M LCD monitor presentation posted by another poster on this forum, I am convinced that this is a performance limitation of the technology. I'm afraid we are going to have to accept this fact and accept our imperfect displays as they are.

Presentation was interesting and I learned a lot from it. It seems the yellow tint is a phenomenon related to viewing angle and the type of film applied to help improve the viewing angle. Although the presentation did not specifically discuss the phenomenon as it relates to in-plane switching, but I suspect it is not eliminated with that technology.

Jacques LAPORTE wrote:
Panels using this LEDs technology are particularly difficult to build with color uniformity due to operating temperature gradient on the array of LEDs (variation in temperature can be responsible for shifts in the emission spectrum). This is the thermal management issue pointed by Apple in its Patent. This is IMHO the current state of the art *in this grade of displays* ... (the problem name is 'backlighting' not LG, Samsung or whatever).

This is my conclusion too.

But another added issue is that the emission equilibrium of the LEDs has a relatively long stabilization phase, making the measurement in the production environment a challenge.

Jacques,
do you think there could be a relation with 'burn in' of LCDs? See the third post in this thread:

http://forums.macrumors.com/showthread.php?t=881489

do you think there could be a relation with 'burn in' of LCDs?

I don't believe this is the case with regard to the gray band across the bottom that people are seeing and that has been present with my original iMac, my replacement LCD, and my second iMac.

When I first saw it I thought it looked like image persistence, so I wrote a program (ScreenClean - http://www.designeq.com/software/) which flashes a black, gray, and white screen at 2 second intervals. Doing something like this will usually fix image persistence in an LCD after a while. I let it run for 48 hours with no noticeable effect, so my conclusion was that the gray bar at the bottom was a manufacturing problem, not image persistence.

I finally decided to get a full refund for my iMac 27" i7 Quad Core after two replacement machines and two LCD replacements. The yellow-tinge was present in all cases at varying degrees. Rumors are that a 27" LED Cinema Display is coming out...I'm wondering if they will have the yellow tinge problem fixed by then.

Message was edited by: Mutley2008

Howard Bornstein wrote:

I don't believe this is the case with regard to the gray band across the bottom that people are seeing and that has been present with my original iMac, my replacement LCD, and my second iMac.

When I first saw it I thought it looked like image persistence, so I wrote a program (ScreenClean - http://www.designeq.com/software/) which flashes a black, gray, and white screen at 2 second intervals. Doing something like this will usually fix image persistence in an LCD after a while. I let it run for 48 hours with no noticeable effect, so my conclusion was that the gray bar at the bottom was a manufacturing problem, not image persistence.

Thanks for your reply. Did you also try this for the yellow tinge?

Hi guys,
I've just received my first iMac 27'' replacement.
The first one had yellow tint on the first 1/3 lower part of the display.
This one is better as far as yellow is concerned but it has a grey band in the bottom part of the screen from left to right.
What do you think about it ?
Please have a look at it:

http://i43.tinypic.com/inuxj5.jpg
http://i43.tinypic.com/2kpvsl.jpg
http://i44.tinypic.com/20qygyv.jpg
http://i41.tinypic.com/abp4qg.jpg
http://i40.tinypic.com/30vycmt.jpg

Many thanks.