What uses more juice, default mode or dark mode?

[Luffy]

Hope someone can enlighten me on the matter.

[j.p.s]

Originally Posted by Luffy

Hope someone can enlighten me on the matter.

Should be the same.

[Luffy]

Originally Posted by j.p.s

Should be the same.

Thanks. Others are free to chime in.

[hobnail]

I would guess dark mode would since it has to turn on more pixels, and then only if you're turning pages at a furious rate. On the other hand I have page refresh set for every page so it wouldn't make any difference for me.

[j.p.s]

Originally Posted by hobnail

I would guess dark mode would since it has to turn on more pixels, and then only if you're turning pages at a furious rate. On the other hand I have page refresh set for every page so it wouldn't make any difference for me.

The number of pixels changed is the same for either mode. The "pixels" are a bunch of half-white half-black spheres whose orientations are changed to control the shade of gray.

[Luffy]

Originally Posted by hobnail

I would guess dark mode would since it has to turn on more pixels, and then only if you're turning pages at a furious rate. On the other hand I have page refresh set for every page so it wouldn't make any difference for me.

Well, I hope to get more constructive views before making up my mind.

[hobnail]

Originally Posted by Luffy

Well, I hope to get more constructive views before making up my mind.

The edges of the letters may change depending on the mode. This is certainly true with print and crt, lcd, etc. due to bleed, but I don't know if it's an issue with e-ink. Back in the days of crt monitors my favorite font looked great with white text on a black background but changing it to black on white made it horrible. CRTs no doubt have a lot more edge bleed than LCDs and e-ink.

[j.p.s]

Originally Posted by hobnail

The edges of the letters may change depending on the mode. This is certainly true with print and crt, lcd, etc. due to bleed, but I don't know if it's an issue with e-ink. Back in the days of crt monitors my favorite font looked great with white text on a black background but changing it to black on white made it horrible. CRTs no doubt have a lot more edge bleed than LCDs and e-ink.

Those are appearance issues that have nothing to do with power use for e-ink devices.

[hobnail]

Originally Posted by j.p.s

Those are appearance issues that have nothing to do with power use for e-ink devices.

Agreed; I thought I'd point it out so that there's more to consider in the long run.

[JSWolf]

It takes more power to switch modes. But once switched, it should take the same as it would be the same changes after that. But there is one difference that I've found. I've found that in night (dark) mode that the light needs to be at a higher level then it does iday (normal) mode. That will take more power.

[DuckieTigger]

I would say dark mode uses more power when reading in low or no light, because it needs more front light to create enough contrast. Normal only needs enough light to make the white background visible.

I concur with Jon in last post. Also the front light is always on on Oasis, cannot be turned off in dark mode.

[Luffy]

I've got a PW4. I think I've been dealt a good hand since I never read in an unlit room.

[j.p.s]

Originally Posted by JSWolf

It takes more power to switch modes. But once switched, it should take the same as it would be the same changes after that. But there is one difference that I've found. I've found that in night (dark) mode that the light needs to be at a higher level then it does iday (normal) mode. That will take more power.

Originally Posted by DuckieTigger

I would say dark mode uses more power when reading in low or no light, because it needs more front light to create enough contrast. Normal only needs enough light to make the white background visible.

I concur with Jon in last post. Also the front light is always on on Oasis, cannot be turned off in dark mode.

Switching modes uses more power, but that has nothing to do with power use in a mode.

For some people, light setting #1 is too bright for reading in a dark room. For them, dark mode would not use more power unless Setting #1 is too dim in dark mode.

I agree that the screen is darker in dark mode and might require setting the light higher.

I measured Voyage battery drain versus light level a couple of years ago and it was pretty much impossible to tell any difference between levels 1 - 6. I'm sure the drain from the light is more than 6 times greater for level 6 than for level 1, but all the other things draining the battery on the Voyage just swamp them out.

https://www.mobileread.com/forums/sh...d.php?t=293683

The KOA2 light draws more power than the Voyage light, but I bet the difference in the first 4 levels is tiny compared to all the other drains.

Almost three years ago, I compared Voyage and KOA2 brightness at many light settings in a dark room, with the KOA2 in both mormal and dark modes.

https://www.mobileread.com/forums/sh...d.php?t=292336

[tomsem]

It seems we agree that only the front light intensity matters when it comes to power consumption.

On the Paperwhite (and I assume Oasis) it is worth noting that Dark and Light modes have independent front light settings.

In my case, Dark is set to a lower setting, so I’m ‘saving power’ when I use it. It’s higher for Light mode because in average light, I like the background to appear whiter, and when in Dark mode, I like the background to appear darker.

That said, I pay almost no attention to power consumption rate.

[hobnail]

Originally Posted by tomsem

That said, I pay almost no attention to power consumption rate.

Maybe it matters if you're going backpacking on a long trek. In that case I'd look into a solar panel charger.