27", 21.5" iMac Owners, test your screen for yellow tint issue here

Discussion in 'iMac' started by tapplox, Nov 22, 2009.


Is your display having the problem described?

  1. iMac 21.5" both grey bars look identical in color

    102 vote(s)
  2. iMac 21.5" the bottom bar looks more yellow

    199 vote(s)
  3. iMac 27" both grey bars look identical in color

    311 vote(s)
  4. iMac 27" the bottom bar looks more yellow

    531 vote(s)
  1. macrumors member

    Oct 17, 2009
    February 8th. Apple has initiated steps to rectify the Yellow Screens with a one-time only screen replacement service. The repair/replacement service are quoted to take 3-5 days.

    Theory on the cause, and an Apple memo via Gizmodo.
    Macworld article

    Test Instructions:
    Go to the link below with the height and width of your window maximized,


    1. While focussing your eyes on the grey bars at the bottom
    2. Resize the height of your browser window so that the grey boxes are almost touching
    3. Resize the browser back to full size
    4. Repeat steps 1-3 several times. Do the test while you are looking directly at the screen, do not tilt your screen up or down. Align your eyes perpendicular to the screen.

    Note: Your screen may have the yellow tinge on a corner as opposed to the entire bottom.
    The following links might be useful to help you look for them.
    Top vs Bottom grey bars (single color)
    Left vs Right grey bars

    Confirm whether or not the two bars look indistinguishable in color during the entire test. There maybe slight variability in LCDs, but there should not be a significant color shift. Most of the displays with the issue have a noticeable much warmer (yellowing) tone towards 1/3 bottom of the screen, as illustrated in the photos below:

    P1020039.JPG.jpeg P1020040.JPG.jpeg

    Tip: The grey bars will look identical in color when they are close together (near the top of the screen). The yellowing issue starts from the middle towards the bottom of the screen.

    Tip: The issue will appear to be more severe and more apparent in dark room conditions (preferably with all lights off). It will also be much more apparent if you lower the brightness. Try doing both if you are not sure whether your display has the problem. Do try to play with ambient lighting conditions, sometimes in a very bright environment the yellow tinge is much more subtle.

    Warning: Do Not Tilt the Angle. If you do tilt the screen upwards, the yellow will fade — BUT as this happens, the top of the screen turns Purple, which will be more difficult to notice in grey. Anyway, nobody should be using their iMac in such a way. If you are doing the test, try to align your eyes normally.

    Note: Other forms of color uniformity issues maybe present. There are reports of honeycomb yellowing patterns, yellow band that run horizontally, yellow band that run vertically, and or significant splotches of yellowing towards the lower left or right corner. These maybe developed from the same problem documented here.

    Carefully observe the differences. While there are slight variability for LCDs, there should not be a significant color shift/cast. The color uniformity for LED IPS panels should be very acceptable.

    After you have done the test, please vote in the poll.
    Please keep in mind that this test was designed to make the "yellow tint" easier to spot. Making an unacceptable display easily identifiable. If you can't really tell after the test, chances are it is probably an acceptable display. If the display appears to be highly acceptable to you (in regards to color uniformity), though it might have a very mild color shift, there really isn't much to worry about so long as it does not affect your day to day usage. But do keep in mind that while your display might look acceptable in your eyes, it might not be the same for some others.

    This poll applies to new iMacs only. Do not vote otherwise.

    If your display shows identical colors after doing the test several times, it means that your display has no such issue. If you could list your week number for your iMac here it will help Apple track down units. If your display has other related issues, you can describe it below.

    Alternative Tests

    1. Open a finder window and expand it to the full screen. Use the detail view with 'White & Blue' separators. If you have the yellow tinge it should be very easy to see the uneven color uniformity.

    2. You can try using an app window's grey color (Finder, Safari, Mail, etc). Simply observe the color of the window while it is to near the top and then dragging it down towards the bottom. If your display is affected you'll see the grey shift to a warmer (yellow) tone.

    3. Alternatively you can set the background as a white or grey wallpaper. Personally I can spot the yellow with the default purple Snow Leopard Wallpaper, but not everyone's eyes are trained to spot the difference. Due to the varying degrees of severity of the issue, it might be more or less difficult to tell.

    Helpful and Diagnostic Information:

    1. Yellow Tinge is a color uniformity issue for both 21.5" and 27" iMacs
    2. Not everyone have the issue, but it is extremely common.
    3. There's a difference in severity of yellowing. Some reports cite that yellowing worsens over time while there are some that said it had remained the same.
    4. The issue is NOT a backlight leak nor backlight inconsistency. This is a color inconsistency issue. If you desaturate photos taken of the yellow tinged display, you will see even backlighting.
    5. It is not GPU specific. Reported issue seen on Nvidia 9400M, ATI HD4670, ATI HD4850.
    6. It is not CPU specific. Seen on Core 2 Duo, Core i5, Core i7.
    7. It does not affect External Displays, only present on the iMac 21.5/27 display.
    8. Also occurs in Windows running in Bootcamp, so it is very likely a hardware defect.
    9. PRAM reset does not help. Reinstallation does not help.
    10. Issue remains regardless of brightness level.
    11. Issue remains regardless if display is near speakers / magnets.
    12. Issue remains regardless of viewing angle. Looking directly, up or down or from the side. Watch for it carefully.
    13. Some displays may have more yellowing on the left, center or the right side of the affected area (from mid towards the bottom).
    14. Some of Apple's 24" LED Cinema Display also exhibit this issue.
    15. First batch of refurbished 21.5" iMacs also exhibit the issue.
    16. This is not a discoloration of the glass itself.
    17. The firmware update from December 21st 2009 does not fix the issue.
    18. Previous generation 24" iMac's yellow tint issue, link, is similar but goes horizontally across the screen.
    19. This may not be a LED problem.
    20. The firmware update from February 2010 does not fix the issue.

    Breakdown of reports for Week/Batches
    To find out about your unit's Week/Batch number, look at your serial number.
    W8947XXXX — translates to Week 47

    Week 39: One 27" with extremely subtle yellow towards the very bottom. And one 21.5" that is yellow-free.
    Week 40: Not all are yellow-free.
    Week 41: Not all are yellow-free, but are mostly good.
    Week 42: Normal display reported.
    Week 43: Unknown.
    Week 44: Yellow Tinge and Non Yellow Tinge cases reported.
    Week 45, 46, 47: A lot of these exhibit this issue. They are the more pronounced than other weeks.
    Week 48: There have been a few real Yellow free screens. But still many with the issue.
    Week 49-51: Many reports of Yellow Tinge, some more subtle than previous weeks, some worst (especially week 51). More recent week 51 units reported without the issue (but not confirmed by tests).
    Week 52-53: Still many reports of yellow tinge..
    Week 02-03: Might have been less reports of the problem, but still many.

    Refurbs: First batch of 21.5" iMacs have the issue. No data on newer batches.

    Some reports cite that they worsen overtime. Some more severe than others—especially after a full day of use. Except for exceptional cases of a perfect display, like some of the week 41 batch.

    Evidence of week 40/41 yellow free displays.

    Possible Cause

    Apple is out of 27" Display (parts) as of February 3rd, 2010

    Apple's Memo

    Latest Apple's Official Response(s)

    Links to other related discussions

    Yellow Tinge Photos

    Yellow (left) vs Yellow-free (right) 27" iMacs. Photo courtesy of Mitch Aunger

    Greybars 100% brightness.
    Yellow tinge bottom right (left), Yellow vertical stripe center (right). Photo courtesy of knewsom

    Finder (details view) test at 50% brightness.
    Yellow tinge bottom right(left), Yellow vertical stripe center (right). Photo courtesy of knewsom

    Finder (details view) test at 100% brightness.
    Yellow tinge bottom right (left), Yellow vertical stripe center (right).
    Note carefully that, when compared to 50% brightness in the photo above, higher brightness levels tend to hide the yellowing slightly. Photo courtesy of knewsom

    Non-Yellow uniform screen. Courtesy of robotkiller.

    Yellow 1/3 Bottomon with White. Courtesy of Big iMac.
  2. macrumors 6502

    Oct 15, 2008
    My symptom is not covered. The bottom bar is not really "yellow" but the right hand of the bottom bar (from about the middle onwards, it is lighter than the top bar. Using a solid background I can see that's it's pretty much the whole lower right quarter that is affected. It is quite subtle though, and I didn't notice until now...hmm:mad: More noticeable is a dark shadow band that runs along the length of the screen near the bottom. Again, only noticeable on solid backgrounds, and mainly on the left hand side this time...

    How sure are we that it is the LED backlighting that is causing these problems? It seem the backlight should be the easy part :)
  3. thread starter macrumors member

    Oct 17, 2009
    While I was speaking with the Tech Support at Apple, they suggested that the GPU (Graphics Card) could be the issue. I can see how an average user might not notice this, but for a graphic designer who stares at pixels on a minute-to-minute basis, you just cannot use it.

    Those of you who have the display with no problems, could you tell us your GPU? And I guess the same for those of us who are having the issue.
  4. macrumors newbie

    Oct 31, 2009
    I had the problem with my 21.5" with Nvidia 8400. I returned it.

    The two batchs that the premium reseller received were affected by the same problem.

    I am waiting for the third batch.

  5. thread starter macrumors member

    Oct 17, 2009
    385 views and only less than a couple dozen votes...

    From I can gather outside this poll, this seems to be a 50/50 issue. And if this poll is an indicator of anything, we are seeing similar results.

    Sadly for our two Quad iMacs, both running HD4850 are packed up and ready to go back.

    Those of you who get a chance to go to Apple Stores, you can also help out by testing the screens in the stores. Remember these are IPS class panels, meaning no matter which angle you are looking at the screen, provided you are close enough, you should not any uneven coloration / temperature.
  6. macrumors member

    Sep 7, 2008
    I also posted this on the Tinge topic:

    "Second iMac 21.5" and also having this issue. It even seems worse tinge than the previous one which I returned.

    The HD on this one(Seagate 1TB) is more quiet though and also no dead pixels or screen-glass gaps. Week 89 model.

    So close for a perfect one, damn :p"
  7. thread starter macrumors member

    Oct 17, 2009
    Hey guys, I have updated the test page with another grey color to make it slightly more easier to see the yellow tinge issue.

    Updated instructions on first post. Don't forget to vote.

    Also remember that there's no point in testing anything if you don't maximize the height of your browser window. So don't forget to do that.
  8. macrumors regular

    Jun 25, 2005
    I have 27" iMac and I notice the bottom being more yellow.
  9. macrumors 6502a


    Jun 25, 2008
  10. macrumors member

    Nov 13, 2009
    Gold Coast, Australia
    I received my i5 last Thursday and I have been trying to ignore the yellow tinge at the bottom. I decided I wasn't going to settle and called Apple tonight. They made me go through all the usual hardware tests which of course didn't make a difference.

    They are going to give me a $50 voucher but to use it for the new iMac I have had to get a refund on this one and will purchase another when the refund has been processed. I am so disappointed and I really hope the new one will be ok. Other than the slight yellow tinge there are no other issues with this one. I hope I am doing the right thing............
  11. macrumors member

    Feb 28, 2008
    I never noticed it before the test so it's no big deal to me, but I can see how it could effect others.
  12. thread starter macrumors member

    Oct 17, 2009
    Those of you who can 100% confirm that you don't have the issue after doing the test several times, if you could please list the week number for your iMac for the rest of us. I know it's not going to be very useful, but it will help Apple to track down certain units (it seems that there are a lot of people already getting replacements due to this problem so they must care).

    This thread below from Apple's discussion board seems to indicate that 100% of users have this issue there, but there isn't enough data.

  13. macrumors 6502a


    Oct 26, 2007
    Here, there and everywhere
    Mine apparently has the problem too, to say I am crestfallen by this is an understatement. The machine is otherwise perfect. No dead pixels, no dust under screen, hd is quiet (not silent but quiet), fan is barely audible.

    The downside is the bottom right, from about midway across the bottom, to the bottom right is yellower than the top of the screen.

    What is interesting are the backlights, look at the bottom right. It is white, where the other 3 have a more yellow look. This was a solid black background, in a dark room, with screen at full brightness

    I'm struggling with this a bit, my wife is telling me to live with it. Nothing is perfect but I find it difficult knowing and seeing a problem. Someone else has advised keeping it till Apple have acknowledged the problem and starting rectifying it.

    After the problems I had with the 24" LED display (bad backlight bleed, dead pixels, dust under the screen) I am not keen to go through the problems again.

    [EDIT to remove linked pic from Twitpic and uploaded as an attachment]

    Attached Files:

  14. thread starter macrumors member

    Oct 17, 2009

    If it makes you feel better, I have just returned my unit as well. Apple did offered to do screen replacements anytime but whether or not the issue will be fixed isn't guaranteed. As someone else has already mentioned it doesn't make sense when you'll have to test your colors on another screen because the iMac display isn't looking as good as your old iMac/Cinema Display/Other screen.

    If this poll is an indication of anything, it seems that there are quite a few of iMacs with no issue so it's likely that it was just a manufacture defect for some of the earlier batches.
  15. macrumors 68020

    Sep 27, 2008

    Great thread and good work on trying to track things down! I like your approach. It may very well help sort some things out.

  16. macrumors 6502a


    Oct 26, 2007
    Here, there and everywhere
    I've just spent the last 41 minutes on the phone with AppleCare and organised an exchange & return for the iMac. They'll get mine once the new one arrives.

    Tried living with it but its annoying & distracting to look at an upper finder window and its one colour and then down at one and see its a different shade.
  17. macrumors newbie

    Nov 16, 2009
    I'm on my second i5 from an apple store.
    I thought the tinge was gone on this second one at first.
    BUT, I was wrong and it is there again.
  18. macrumors newbie

    Nov 27, 2009
    Both screens has no yello tint

    Imac 27" 3.06 c2d, 4gb Ram, 1 TB HD
    Purchased from University Village Store in Seattle 11-17-2009

    Imac 27" Core I7, 4gb Ram, 1 TB HD
    Purchased from Apple Online Store 11-17-09, shipped from China 11-25.2009
    Arrived in seattle 11-27.09
  19. thread starter macrumors member

    Oct 17, 2009

    Markomcm, thanks.

    This kind of information is very helpful and hope reviving. If you can, do keep us posted if the issue ever comes back within a few days. This is starting to look more and more like just a LCD defect.
  20. macrumors 6502a


    Oct 26, 2007
    Here, there and everywhere
    That is great to know, gives mr hope as just tested 4 store models (non apple store, 2x21.5" & 2x27") and they all had it but they've been there a while now.

    What I did also not on a 17" MBP is that it had a slight yellow tinge in the top right corner but was fine in the bottom right.
  21. cxc
    macrumors member

    Nov 30, 2007
    Cologne, Germany
    My recently arrived i5 W46 also suffers from clouding (yellow tinge) in the bottom third of the screen. It´s not nearly as bad as with some of the 24" I have sent back. However, I will go through the motions with Apple and exchange my 27" for a new one. Hopefully, I´ll get lucky next time around. Other than the tinge, baseline screen quality is much better than on the 24" models.

    Good luck to everyone!
  22. macrumors newbie

    Nov 25, 2009

    After testing several different models in several different stores today, only one 27 inch iMac model showed acceptable white levels in the screen.

    I tested 5 x 27" models, 2 x 13" macbooks, 3 x 21.5 inch imacs and 3 x 24 inch displays.

    All had glossy screens and all of them, except the macbooks, exhibited some degree of yellow tinge in the screen.

    I used tapplox's test HERE

    I think you'd have to be very lucky to get a screen with no yellow tinge.
    I honestly don't even know if that's possible to find at the moment.

    I am a graphic and fashion designer and my eyes are trained to spot slight colour differences, so maybe that makes a big difference.

    Here's hoping that Apple find a way to deliver 'clean' displays asap.

  23. macrumors newbie

    Nov 27, 2009
    No problem

    I hope you're replacements are free of any screen issues, so far both machines have been great and I'm keeping my fingers crossed that they stay that way.
  24. macrumors regular

    Oct 21, 2009
    Will they just exchange it, or do I have to have a genius check it out before they will let me do it. I'm worried some geek won't be able to see the yellow...
  25. macrumors member

    Nov 19, 2009
    My machine is otherwise perfect, but I can't seem to make a decision about whether to return or repair my iMac over this yellowing issue...

    I've seen this issue before in the 2008 MBPs... I didn't like the issue then and I don't like it now.

    I'm curious if there is any kind of utility that will allow me to overlay a gradient in the opposite direction, meaning since this screen's color temperature shifts from bluish to yellowish (from top to bottom) I could apply a yellow-to-blue gradient to normalize the color temperature.

    Then I'd be happy about this and not care about the underlying issue. I've dealt with the same problem for years on my Dell 2407WFP, which was infamous for a darkening issue to one side. It was unacceptable for a while, and then it was just a nag, and then I ended up forgetting about it entirely.

    So I'm wondering if this problem will go the same with me, and maybe I should just accept it and forget it.

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