Does dark mode improve battery life?

Discussion in 'macOS Mojave (10.14)' started by vannibombonato, Jun 4, 2018.

  1. vannibombonato macrumors 6502

    Joined:
    Jun 14, 2007
    #1
    As per subject: is it reasonable to expect that dark mode will give a big boost in terms of battery life? In theory it is equivalent to turning way down brightness, which is possibly the biggest battery eater during "normal" usage (browsing, email, office, etc.).

    Any beta user?
     
  2. koifish22 macrumors member

    koifish22

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    Sep 2, 2014
    Location:
    Pale Blue Dot
    #2
    No. Macbooks don't have OLED screens that would take advantage of dark pixels.
     
  3. DerfBWH macrumors 6502

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    Aug 11, 2008
    #3
    That's not how the display technology used on any modern Mac works. The displays light up every pixel exactly the same no matter what color is being generated, with blacks having no impact on battery life whatsoever.

    OLED displays however, which Apple uses on iPhone X and Apple Watch, power pixels on an as-needed basis, leaving totally black pixels in an "off" state. If Apple were to release a Mac with one of these OLED displays, then Dark Mode would absolutely result in a battery life.

    We'll be waiting a long time for a Mac with an OLED display, however.
     
  4. redheeler macrumors 604

    redheeler

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    Oct 17, 2014
    #4
    Dark mode would only improve battery life on an OLED Mac, which does not currently exist. LCDs feature an always-on backlight, no matter what is on the screen.
     
  5. vannibombonato thread starter macrumors 6502

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    Jun 14, 2007
    #5
    I trust you guys are right, but i don't scientifically get it:

    i don't understand how the amount of energy needed for a bright white screen, which is capable of lighting up the surroundings in a dark room, can be the same of a black screen which won't be illuminating anything, unless there is some kind of "shielding".

    Edit: there indeed is some kind of shielding. Apparently a white background uses LESS energy.

    https://www.quora.com/Does-a-white-background-use-more-energy-on-an-LCD-than-if-it-was-set-to-black

    Amen, topic closed.
     
  6. Internet Enzyme macrumors 6502a

    Internet Enzyme

    Joined:
    Feb 21, 2016
    #6
    And even if they did, the dark theme is simply a shade of grey, not complete black. So the pixels are still setting their rgb values to a value other than 0,0,0.

    What affects battery life is the luminance the display sets these rgb values at. All rgb combinations require the same amount of battery life to display
     
  7. RumorConsumer macrumors 6502a

    RumorConsumer

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    Jun 16, 2016
    #7
    Yeah backlight is always on, pixel colors is additional work
     
  8. Rev0l2ti0n macrumors newbie

    Rev0l2ti0n

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    Aug 21, 2015
    #8
    As is mentioned above, you'd best benefit from having the lightest possible set up and then reducing brightness.
     
  9. stooovie macrumors 6502a

    Joined:
    Nov 21, 2010
    #9
    No, especially in current beta in which Dark mode behaves almost like the Smart invert on iOS - it almost looks to do some reshading on the fly, making everything lot less smooth. My rMBP 2015 was perfectly smooth on HS, now it's very jerky EVEN with transparency turned off.
     
  10. banach macrumors newbie

    Joined:
    Jul 7, 2018
    #10
    Not a beta user, but I regularly switch to using a custom dark theme to save battery life when I am in the air. At least to my eyes, it is easier to discern white text on a dark background, so I can turn down the brightness very low and still remain productive, compared to using a bight-on-dark theme. I expect this to carry over to the dark mode in Mojave.
     
  11. boast macrumors 65816

    boast

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    Nov 12, 2007
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    Phoenix, USA
    #11


    It's an interesting watch to learn how an LCD works.
     

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