Comment by lloeki | Hacker News Reader

Comment by lloeki | Hacker News Reader

> Also, Dark Mode helps to reduce exposure to Blue Light

What. No. Most of the harmful blue light comes from LCD backlight (of course it does not apply to OLED as much).

This kind of misunderstanding is why there have been so many dark mode or low contrast themes (like zenburn), which is a failure to recognise that what you have to turn down is screen brightness.

Like loudness wars for music it may be more pleasant to have nice brightness for a couple of seconds, but here’s my take: set brightness to a satisfactory value, then turn it down (a bit, maybe more). Your eyes will adapt. Over the course of a day facing a screen (which is basically a flashlight) it makes a massive difference. As a bonus when unplugged this saves crazy battery life.

> Since not everyone can see well with Dark Mode, some mobile devices provide the option for Blue Light filters

Huh. f.lux & al are not an alternative to dark mode, one should definitely use such settings, even with dark mode.

Final tip: pay attention to ambient and bias lightning.

The dark portions of the screen block the backlight, so the darker it is, the less light gets to your eyes.

In a low luminosity environment, you will get better contrast with less emission if you have most of your screen dark and slightly more backlight than with most of it lit and less backlight. You will want to adjust the light anyway, but the dark mode is theoretically a gain.

But all of that is moot anyway, because the web doesn't work in dark mode. So if you try to go with it you will keep being exposed to high brightness at random, what is much worse than any alternative.

> The dark portions of the screen block the backlight, so the darker it is, the less light gets to your eyes.

On (S/AM)OLED screens the black colour (true dark) is simply zero light.

It seems the "excepting OLED" clause is taken for granted? (shrug)

The web works in dark mode if you have Dark Reader.

Kinda. There have been a lot of improvement since last time I tried it. But images are still a problem, and I don't think that will ever change.

> The dark portions of the screen block the backlight, so the darker it is, the less light gets to your eyes.

If you think it blocks enough backlight you’re deluding yourself. Display a pure black image (with a small white square in the middle to defeat dynamic contrast) and turn off the screen. From TVs to laptops, as long as it’s LCD the difference is obvious.

I've tried lowering brightness multiple times, but the decreased contrast and color vibrance that causes on backlit LCDs always bugs me too much, and then I crank the brightness back up.

On my phone it's a different story, since it's OLED. Especially in lower light reducing brightness has little impact on contrast and vibrance.

Can't wait for OLED or microLED to become the standard in desktop and laptop displays so we no longer have to deal with the drawbacks of backlights.

I see both of these as transitional technologies until SED and its laser variant are up and operational en masse.

These are superior in color, brightness and smoothness much like CRT, without most drawbacks.

I don't understand your counter argument. Dark mode blocks most light, so dark mode does reduce exposure to blue light.

(Not that it is designed for blue light blocking per se).

It doesn't actually block that much light, all told? Especially if you then keep the brightness up, you just have smaller things that are super bright. Probably compounded, as your eyes are adjusted for less light. At least in light themes, your eyes completely adjust to block more light.

Though, again, the point is more that even with dark mode, turn down the brightness. (I think. Not original poster.)

> It doesn't actually block that much light, all told?

It does. I'm using a dark theme for HN with a background of #222 and text of #CCC on my Dell U2412M display with the brightness at 100%. I measured with the ambient light sensor in my old Nexus 5 held up to my head. While lux values from smartphones are uncalibrated, it's the ratios that matter.

Dark theme, backlight 100%: 1 lux

Light theme, backlight 100%: 54 lux

Light theme, backlight 0% (not actually off): 7 lux

What is dark with backlight down? I'll try the lumen sensor when back at a computer. Where do you see the values?

And my hypothesis was more that the bright parts are still bright. It is obviously less overall, but the small things are still hitting your eyes. Potentially worse, as your eyes aren't dilated correctly for the brightness.

It reads zero from eye distance when dark with the backlight down. Here are readings from contact distance:

Dark 100%: 5 lux

Light 100%: 103 lux

Dark 0%: 0 lux

Light 0%: 14 lux

Someone is going to ask for a wavelength soon, so get ready to calibrate for 450–485 nm :)

If anybody wants to buy me a spectrophotometer, I'd be happy to take measurements. Those things are pricey.

For my part, thanks for the measurements! I do intend on trying this when back at a computer. At face value, not seeing anything suspicious on these numbers. Bottom line, do not run a bright screen in the face. Darker colors do look to help, but so does dropping brightness. If worried about your eyes, do both.

In my HDR mode settings, tuned for bright conditions, it is:

0% PQ: 0.12 nit

0% SDR: 0.2 nit

100% SDR: ~120 nit

100% PQ: 570 nit

It works better in dark mode than your low contrast. The screen does not support local dimming.

I missed what pq and sdr stand for. :(

> Dark mode blocks most light, so dark mode does reduce exposure to blue light.

This is completely false and the very raison d’être for developing OLED (plasma had this for TVs but the power consumption was ludicrous). See my sibling comment.

completely false?

I can see how it is marginally false, say with a blue-themed dark mode.

Or maybe marginally false, with a cheap LED screen with a terrible contrast ratio.

Or completely not-false, with a non-blue-themed OLED dark mode.

Or mostly non-false possibly with local dimming.

but calling it completely false is completely psuedodoxical.

:)

The trick I found was to use your phone camera. If the preview pointed at your desk washes out, your monitor is too bright. Mind blowing that I now have my monitor at about the lowest setting. Don't know how I used to deal with it at the brightest.

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