> Color pixels drain more energy than grayscale ones. Personally found my phone lasting twice as long as before. Over time, a considerable extension of your phone’s lifespan.
What? Why? Why would you even entertain that as a hypothesis?
They said they found themselves using their phone far less due to the grayscale, which would be the real thing extending battery life here. Or at least, this was what I assumed on reading.
That is likely. Another factor that came into my mind is the gpu using less power due to simpler computations. You can store less data for grayscale, so you need to go over less pixel data to do effects etc. Whether accessibility controls achieve this or not would be implementation dependent I guess.
I questioned the same thing over a decade ago with my then-shiny Samsung Galaxy S5: At the lowest of its low-power battery-saving modes, it drained the color from the screen and made it greyscale.
Perhaps it can make sense for LCDs: After all, LCDs operate by blocking backlight.
Blocking less backlight (by area) by using greyscale might make sense: It seems obvious that a higher perceived brightness can be achieved for any given pixel if using greyscale instead of using colors, just because less of the backlight's area is occluded.
And then: Usability can be maintained while also reducing backlight intensity.
Reduced backlight intensity definitely does have a big effect on battery life.
So -- for LCDs -- it might make sense.
(But even if it makes sense for LCD, the S5 happened to use one OLED variation or another, not LCD. Perhaps there's a non-linear relationship between subpixel brightness and power consumption, and keeping 3 subpixels (RGB) barely-illuminated is more efficient than keeping 1 subpixel (G, say) more-illuminated is?
Or, what I determined to be most-likely at that time: Samsung was simply an uncoordinated wreck that was full of shit.)
> It seems obvious that a higher perceived brightness can be achieved for any given pixel if using greyscale instead of using colors, just because less of the backlight's area is occluded.
When converting to grayscale, you typically calculate the value of the pixel and then set all color components to that value. The point of this is to keep the luminance the same as it was in the original color pixel. If you’re doing this correctly, the perceived brightness stays the same.
And just as a smell test: have you ever converted an image to grayscale and flinched away because it seemed twice as bright? Of course not; it just loses its color.
The only way you would get more perceived brightness at lower backlight intensity would be if you physically removed the color gels that overlay the LCD matrix. Which is obviously not what they’ve done here.
I’m pretty sure the increase in battery life they observed is simply because they’re using their phone less, which is very much the main upshot of the other benefits they listed. The idea that color pixels drain more energy is just obviously nonsense.
D-Machine|2 months ago
musebox35|2 months ago
mistercow|2 months ago
ssl-3|2 months ago
Perhaps it can make sense for LCDs: After all, LCDs operate by blocking backlight.
Blocking less backlight (by area) by using greyscale might make sense: It seems obvious that a higher perceived brightness can be achieved for any given pixel if using greyscale instead of using colors, just because less of the backlight's area is occluded.
And then: Usability can be maintained while also reducing backlight intensity.
Reduced backlight intensity definitely does have a big effect on battery life.
So -- for LCDs -- it might make sense.
(But even if it makes sense for LCD, the S5 happened to use one OLED variation or another, not LCD. Perhaps there's a non-linear relationship between subpixel brightness and power consumption, and keeping 3 subpixels (RGB) barely-illuminated is more efficient than keeping 1 subpixel (G, say) more-illuminated is?
Or, what I determined to be most-likely at that time: Samsung was simply an uncoordinated wreck that was full of shit.)
mistercow|2 months ago
When converting to grayscale, you typically calculate the value of the pixel and then set all color components to that value. The point of this is to keep the luminance the same as it was in the original color pixel. If you’re doing this correctly, the perceived brightness stays the same.
And just as a smell test: have you ever converted an image to grayscale and flinched away because it seemed twice as bright? Of course not; it just loses its color.
The only way you would get more perceived brightness at lower backlight intensity would be if you physically removed the color gels that overlay the LCD matrix. Which is obviously not what they’ve done here.
I’m pretty sure the increase in battery life they observed is simply because they’re using their phone less, which is very much the main upshot of the other benefits they listed. The idea that color pixels drain more energy is just obviously nonsense.