Quote:
Originally Posted by HarryT
No. The "whiteness" of the screen is determined by hardware. There's no way it could be changed by a firmware update.
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Actually, it might be possible. With LEDs, brightness is almost always controlled using
PWM, varying the ratio of on/off. Frequently, it's implemented at a fixed frequency, where when the on time increases, the off time decreases.
White LED color output can vary somewhat when one compares short "on" times with longer ones. That's because the color changes for different currents, and it takes a finite time to turn the LED on or off. So even though the "full on" current stays the same, the average current for each on cycle varies slightly.
So, if one instead does PWM by keeping the on time constant and only changing the off time (and hence the frequency), a more consistent color can be achieved across all levels of brightness. You just need to ensure that the frequency is kept high enough to avoid perceptible flicker. There are other factors which would still cause a bit of color shift (such as LED temperature), but current is the main influence.
I have no idea if the PW hardware supports that, or if newer software does that, but it's not impossible.