So... is a slight brightness gradient normal?

Discussion in 'iMac' started by rpeters83, Nov 25, 2007.

  1. rpeters83 macrumors regular

    Joined:
    Oct 31, 2007
    #1
    I picked up a 24" imac last week and after one exchange for a bad pixel, I was happy. Until I noticed a little bit of brightness gradient. From searching the web and this forum, it seemed like some had it, and some didn't (or at least didnt think they had it).

    Mine is actually quite minimal compared to the pictures, but is this affect considered normal for LCD's? I understand LCD's are an imperfect technology, but does a perfect display actually exist for these 24" imacs? Is a little brightness difference normal from left to right?

    I also have very minor backlight bleed near the top left and bottom left corners, but is only noticeable on full brightness and an all black screen in the dark.

    I just don't feel like going through exchanges; I did that with my macbook and it still isn't a perfect screen.

    Thanks.
     
  2. Techguy172 macrumors 68000

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  3. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #3
    Just took a few pics with my DSLR. Actually, based off the pics, mine doesnt seem too bad compared to other's I've seen.
     

    Attached Files:

  4. Leon Kowalski macrumors 6502a

    Leon Kowalski

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    #4
    That's easily the best 24" ALU iMac screen photo I've seen so far.
    A rough measurement with DigitalColorMeter.app showa a very
    acceptable max:min brightness difference of only 20% or so --
    that would be well within spec for an Apple Cinema Display or
    any other TCO'03-certified monitor.

    If the backlight bleed you mentioned isn't too bad, it's a keeper.

    ...just curious, what's the build date?

    LK
     
  5. JayLenochiniMac macrumors G5

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    #5
    It's normal as far as the technology is concerned, consider yourself lucky you didn't get the very obvious gradient issue that some have had.
     
  6. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #6
    Build date is week 39.

    BTW. here are some more. Might look worse in these due to the light; not sure why the first was brighter. The above one is how it looks in real life though:

    [​IMG]
    [​IMG]

    Left side looks a little cool, a lot like the others I've seen. May be a little less than others though, but doesn't bother me.
     
  7. Leon Kowalski macrumors 6502a

    Leon Kowalski

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    #7
    Yes, I can see some color shift -- but I don't have the tools/expertise
    to measure it or compare it to others. The problem with my ALU 24"
    was mainly the huge brightness gradient rather than any noticeable
    color shift -- and yours is at least 5x better than mine in brightness
    uniformity. (BTW, mine was built in week 34.)

    Overall, I've seen none better.

    LK
     
  8. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #8
    Yeah, I can agree. However, I don't even see the color shift in normal use. The first image above is pretty much exactly what I see during normal brightness and usage.

    Is this color shift caused by the backlight or the panel itself? Thanks.
     
  9. Leon Kowalski macrumors 6502a

    Leon Kowalski

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    #9
    Don't know for certain, but I'd guess it's the backlight -- pixels don't know
    which part of the screen they live on.

    LK
     
  10. ceres macrumors regular

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    #10

    Far too much nicotine yellow tint on most of the screen. Apart from the left 1/3 of the screen I would imagine white color to look like old paper.
    I would not keep this screen. I am waiting for my replacement unit to arrive. If I was to receive something like this it would be sent back for a full refund, a penryn pc workstation and the next 24 ACD.
     
  11. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #11
    Well, as I mentioned, those two pics don't really reflect how the screen looks in real life. These two are really exaggerating the color shift, but cannot be seen easily in real life - which is more like the first image.

    And let me know if you get one that does not exhibit this (I'm still within my 14 day return period). Thanks.
     
  12. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #12
    So, given what you see of my screen in these photos. Do you think I should keep this imac? I'm honestly not sure whether it's worth it to try and get a replacement since it seems like they ALL exhibit this minor issue. Thanks.
     
  13. imacan macrumors regular

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    Montreal, Canada
    #13
    Yours is like mine, cooler on the left and yellowish in the middle. From all those seen in person, you are like the average and changing it right now would probably get you a similar one. I am waiting to see this corrected and ask for a panel replacement via AppleCare if/when it comes. Trying to convince yourself it's not there won't work (it didn't for me) but I can live with it for now.
     
  14. wakerider017 macrumors 68000

    wakerider017

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    #14
    My original week 37 was very bad...

    White on the left, yellow on the right... Terrible!


    My week 46... PERFECT!


    This coming from someone who has seen what a bad screen looked like...
     
  15. rpeters83 thread starter macrumors regular

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    #15
    would you mind posting a photo of your screen on a white background? I'd like to see how perfect it is.
     
  16. imacan macrumors regular

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    Montreal, Canada
  17. SaSaSushi macrumors 68040

    SaSaSushi

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    #17
    Geez, that sounds almost accusatory. I trust him.

    Speaking from personal experience it can be difficult to capture an LCD screen with digital photography. The pictures people posted to the countless "gradient" threads on this forum of solid white walls with gradients are evidence of that.

    As I keep repeating let your own eyes be the judge. The power of suggestion can be a dangerous thing. There is no better tool for aesthetically measuring a gradient than your own two eyes and attached cerebrum.
     
  18. rpeters83 thread starter macrumors regular

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    Oct 31, 2007
    #18
    I agree, what i said does seem accusatory...sorry. I'm mainly just trying to make sure mine is at least better than what's considered "too much gradient" by the boards. If mine is below average, I still have a little over a week to exchange it.

    As I mentioned, the top pic (the whiter one) really represents the screen well. The bottom two really tend to exaggerate the gradient issue.

    As long as I know that mine is at least above average of the bunch, I'll be a happy camper.
     
  19. Leon Kowalski macrumors 6502a

    Leon Kowalski

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    #19
    I can't possibly answer that based on a few photos. I had to live with my 24" ALU
    for several weeks before deciding that I couldn't tolerate the brightness gradient.

    From what I've seen -- in photos and in person -- I believe your chances of getting a
    replacement 24" ALU iMac with better (or even equal) display quality are slim to none.

    After returning two ALU iMacs with duff displays (one 20", one 24"), I gave up on
    finding a decent one and bought a white 20" 2.16 GHz C2D. I'm delighted with the
    display quality, and find the performance quite acceptable. OTOH, I believe both of
    my ex-iMacs were far worse than yours (judging only by a few photos). Here are
    some photos of mine, see if you agree: http://picasaweb.google.com/TheLooby

    good luck,

    LK
     
  20. SaSaSushi macrumors 68040

    SaSaSushi

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    #20
    Hey, no problem. I hope you get exactly what you are expecting. It's an expensive machine and you certainly shouldn't "settle" for anything.

    Your screen looks excellent. I understand your feeling but what if you trade this one in and then get one with dead pixels or some other defect (god forbid a REAL gradient)?

    Once again restating my caveat about photographs of screens as an evaluator I would say yours looks excellent. "I" wouldn't trade it in even if they'd take it back and I don't know that they would.

    Ultimately, its your decision and only your opinion that counts.
     

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