RMBP 13", relationship between heat exit and screen colour unevenness ?

Discussion in 'MacBook Pro' started by MayaTlab, Dec 16, 2014.

  1. MayaTlab, Dec 16, 2014
    Last edited: Dec 16, 2014

    MayaTlab macrumors member

    Joined:
    Dec 12, 2007
    #1
    Hi,

    I've recently tried to buy a MacBook Pro Retina 13" and after exchanging the device four times I finally got a fifth copy which screen I would begrudgingly consider "not too rubbish" in terms of luminance and colour homogeneity, with a moderate amount of bleeding (and that's only relative to Apple's own TFT non-retina laptop screens, which aren't exactly brilliant either, not relative to a pro monitor). I find Apple's manufacturing tolerances with those retina displays to be absolutely abysmally dreadful (only 2 out of five has decent colour uniformity, only 2 had decent luminance uniformity, and only 1 had decent control over bleeding, unfortunately not one had them all at the same time, and by "decent", I mean "like my 2011 MacBook Air with its cheap and cheerful TFT screen"), and it actually prevented from buying an iPhone 6 as well.

    But I've also discovered something that's news to me : whenever I have some load on the mac, near the heat exit (at the right of the screen hinge), the backlighting changes luminance slightly and colour balance a lot : it gets noticeably colder than the rest of the screen. I suppose this is related to LEDs' behaviour with temperature change. Have you noticed the same behaviour ?

    EDIT : pictures in post n°6.
     
  2. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #2
    No

    I've been perfectly happy with all aspects of ny rMBP since I bought it in january.
     
  3. nightlong macrumors 6502a

    nightlong

    Joined:
    Jun 16, 2012
    Location:
    Australia
  4. thundersteele macrumors 68030

    Joined:
    Oct 19, 2011
    Location:
    Switzerland
    #4
    I have the impression that this happens on my 15'' non-retina MBP (high-res antiglare display). The display has severe backlight bleeding on the bottom, and it becomes more intense when the machine is under load.

    My 13'' rMBP has none of these issues. But my eyes are probably not as sensitive as the OPs to colour and brightness fluctuations.
     
  5. MayaTlab thread starter macrumors member

    Joined:
    Dec 12, 2007
    #5
    I'll try to take pictures later this day, but I'm not sure I will succeed.

    I currently believe it's related to the "Air flow proximity" temperature sensor, but I'm not too sure about that - anyway, so far I just have to put my finger on the right side of the hinge, and if it's hotter than on the rest of the hinger, then, voilà, colour heterogeneity galore. Maybe I should start using it with ice cubes taped to the rear of the display ?

    I'm strongly hesitating now to exchange it as it's the first that combines two decent points out of three (colour and with point luminance uniformity), at least when the hinge isn't heating up.

    The alternative would be to abandon altogether the ambition to do a modicum of photo editing with a laptop and go back to my previous ways (a MacBook Air), but it's quite sad given what these displays could do, in theory (not in practice).
     
  6. MayaTlab, Dec 16, 2014
    Last edited: Dec 16, 2014

    MayaTlab thread starter macrumors member

    Joined:
    Dec 12, 2007
    #6
    Here are some pictures. The test protocol was rather simple : camera on a tripod, RMBP roughly in the same place in between shots, same white balance. No additional saturation. A first shot was taken while the laptop was resting, a second one after running two "yes" commands - which aren't even the most taxing things I can think of.

    The first full picture is with no load, the second one with the "yes" commands running.
    The next four pictures are comparative juxtapositions of all four corners. As you can see there is only very minimal differences between the three corners that aren't affected by heat (most likely due to the testing setup rather than anything else), but there is a substantial difference above the volume control keys on the bottom right corner under load (the last comparative picture), and that's not even maxing out the computer processors.

    My apologies for watching bad television.

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