What uses more energy, a black pixel or a white one?

Discussion in 'iPod touch' started by hierobryan, Jan 8, 2008.

  1. hierobryan macrumors 6502a

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    #1
    Place answer here ->

    Just curious....I'm at work reading the Bible on my Touch.

    by the way, I'm talking about an LCD screen.
     
  2. quicklook2 macrumors 6502

    quicklook2

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    #2

    isn't that a sin?

    you are actually stealing time from your employer.

    i think a white pixel.
     
  3. hierobryan thread starter macrumors 6502a

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    #3
    NO! my employer is stealing time from me and my relationship with GOD!;)
     
  4. quicklook2 macrumors 6502

    quicklook2

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  5. uaaerospace macrumors 6502

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    #5
    I think a black pixel requires more energy on a LCD since the backlight remains on and the pixel is completely blocked requiring maximum energy. The white pixel only has the backlight with no energy required to block the light put out by the backlight.

    For a CRT, it would be reversed since no light at all is sent to a black pixel.
     
  6. TuffLuffJimmy macrumors G3

    TuffLuffJimmy

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    #6
    I thought that it was only CRT's that had a difference in power consumption and that LCD had no difference in how much energy is used on all different colors...

    and no, you're stealing from your employer. He isn't paying you to steal from you.
     
  7. iLoveiPod macrumors regular

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  8. OrangeCuse44 macrumors 65816

    OrangeCuse44

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    #8
    Haha, everyday i stumble upon something and wonder how people ever found out about it. Nice work.
     
  9. ChrisBrightwell macrumors 68020

    ChrisBrightwell

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    #9
    I'm pretty sure that, once a pixel on an LCD is set to a certain color, no more energy is needed to maintain that pixel until its color needs to be changed. That is, a black pixel requires just as much energy as a white pixel, but that the energy is consumed in changing each pixel to a new color and is only consumed during that update.

    The real drain is the backlight, which is always shining and always blasting its way through every single pixel on the screen. That's why black isn't really "black" so much as it's "really really really dark grey".
     
  10. goosnarrggh macrumors 68000

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    May 16, 2006
    #10
    What you're describing is true of power budgeting for E-Ink displays. LCD's, however, always require some amount of power even just to preserve their image. It may well be that they use less power to display a static image than to display a changing one, though; but I don't know.

    Remember, though, that there is no such thing as a "white pixel". There are groups of 3 pixels packed in really close to each other - one each for red, green, and blue. As you vary the relative intensities of each of these three sub-pixels, your brain mixes them together to create the perception of different intermediate colours.

    Yep.
     
  11. uaaerospace macrumors 6502

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    #11
    I wonder how much MORE energy is wasted performing the power saved calculations. Not to mention the energy required to run the additional servers. I understand the good intentions of using the site, but don't blindly accept something as being true because someone says it is. You might end up hurting the cause you're trying to help.
     
  12. iLoveiPod macrumors regular

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    Oct 7, 2007
    #12
    Hmm..Where to start. Well, first off, these calculations can probably be done on a solar calculator...so lets not be so dramatic here. Second, i dont use the site at all, its just something i stumbled across. Third, its just a website! No need for all your philosophical babble about blindly accepting things and hurting the world. Thats all.
     
  13. uaaerospace macrumors 6502

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    #13
    haha, my "babble" wasn't aimed at you or anyone in particular. Just a week prior to stumbling across this thread, a friend of mine showed me the site and was all excited because he was saving energy. He knew he was saving energy simply because it was written on the page.
     

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