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"Unless you’re using an OLED or AMOLED screen and your dark mode is truly black – not dark grey, not dark blue, BLACK. There is no difference in power consumpti

"Unless you’re using an OLED or AMOLED screen and your dark mode is truly black – not dark grey, not dark blue, BLACK. There is no difference in power consumption." I thought this was a myth. I looked into it last year and found that power consumption was (roughly) proportional to brightness. At a meta-level, I'm surprised that something with so factual (and testable) an answer can still not be settled.

sadfklsjlkjwt 6y ago
Colour is orthogonal to brightness for LCD screens.
tqi 6y ago
https://www.xda-developers.com/amoled-black-vs-gray-dark-mode/ https://www.xda-developers.com/amoled-black-vs-gray-dark-mod... According to this article there is a difference (between grey and black), but it is very small?
justinpombrio 6y ago
LCD screens are really cool! My dad had a half-broken one at some point, and we peeled the outer layer partly off. It was pure white underneath. Just constant white light, no matter what was being displayed. But if you looked at the pure white with polarized sunglasses, you could see the image! The pixels don't turn on and off, they just change polarization. And there's a thin layer that blocks light of one polarization, but not the other. EDIT: Wikipedia has a picture. https://en.wikipedia.org/wiki/Liquid-crystal_display#/media/File:LCDneg.jpg https://en.wikipedia.org/wiki/Liquid-crystal_display#/media/...
Izkata 6y ago
Things have flip-flopped over the years: CRT - Black didn't light up the pixels (I don't remember the details as to how), so it did reduce power usage some. LCD - Had a constant backlight (see sibling comment for details), so there was little to no difference between black and anything else. OLED/AMOLED - Black LEDs are actually turned off, instead of displaying a dark color, so we're back to it saving power - more even than CRTs did.
- jeffbee 6y ago
  > no difference between black and anything else. Just a detail that isn't quite right in the article: black is actually the highest power state for LCDs. The backlight draws the same power all the time (for a given brightness setting) but the pixels draw more power when they are black.
  - jpambrun 6y ago
    Many monitors now have local array dimming to increase contrast. It's probably fair to assume that dimmed backleds lead to decrease power consumption.
mdwrigh2 6y ago
> At a meta-level, I'm surprised that something with so factual (and testable) an answer can still not be settled. It is absolutely settled, and has been tested over and over again. Power is roughly proportional to the amount of light emitted[1], so having dark grey is absolutely a power savings over pure white. Google slides: https://www.theverge.com/2018/11/8/18076502/google-dark-mode-android-battery-life https://www.theverge.com/2018/11/8/18076502/google-dark-mode... Display energy modeling: https://onlinelibrary.wiley.com/doi/am-pdf/10.1002/stvr.1635 https://onlinelibrary.wiley.com/doi/am-pdf/10.1002/stvr.1635 [1]: This isn't totally true mostly because the display is broken into RGB elements emitting light of differing efficiencies and human perception of the brightness of those elements is not identical.

sadfklsjlkjwt 6y ago

Colour is orthogonal to brightness for LCD screens.

tqi 6y ago

https://www.xda-developers.com/amoled-black-vs-gray-dark-mode/ https://www.xda-developers.com/amoled-black-vs-gray-dark-mod... According to this article there is a difference (between grey and black), but it is very small?

justinpombrio 6y ago

LCD screens are really cool! My dad had a half-broken one at some point, and we peeled the outer layer partly off. It was pure white underneath. Just constant white light, no matter what was being displayed. But if you looked at the pure white with polarized sunglasses, you could see the image! The pixels don't turn on and off, they just change polarization. And there's a thin layer that blocks light of one polarization, but not the other. EDIT: Wikipedia has a picture. https://en.wikipedia.org/wiki/Liquid-crystal_display#/media/File:LCDneg.jpg https://en.wikipedia.org/wiki/Liquid-crystal_display#/media/...

Izkata 6y ago

Things have flip-flopped over the years: CRT - Black didn't light up the pixels (I don't remember the details as to how), so it did reduce power usage some. LCD - Had a constant backlight (see sibling comment for details), so there was little to no difference between black and anything else. OLED/AMOLED - Black LEDs are actually turned off, instead of displaying a dark color, so we're back to it saving power - more even than CRTs did.

jeffbee 6y ago
> no difference between black and anything else. Just a detail that isn't quite right in the article: black is actually the highest power state for LCDs. The backlight draws the same power all the time (for a given brightness setting) but the pixels draw more power when they are black.
- jpambrun 6y ago
  Many monitors now have local array dimming to increase contrast. It's probably fair to assume that dimmed backleds lead to decrease power consumption.

mdwrigh2 6y ago

> At a meta-level, I'm surprised that something with so factual (and testable) an answer can still not be settled. It is absolutely settled, and has been tested over and over again. Power is roughly proportional to the amount of light emitted[1], so having dark grey is absolutely a power savings over pure white. Google slides: https://www.theverge.com/2018/11/8/18076502/google-dark-mode-android-battery-life https://www.theverge.com/2018/11/8/18076502/google-dark-mode... Display energy modeling: https://onlinelibrary.wiley.com/doi/am-pdf/10.1002/stvr.1635 https://onlinelibrary.wiley.com/doi/am-pdf/10.1002/stvr.1635 [1]: This isn't totally true mostly because the display is broken into RGB elements emitting light of differing efficiencies and human perception of the brightness of those elements is not identical.