Using pure red light for the night is a good idea, since it doesn't decrease our eye's ability to see in darkness. That's why it is used in submarines too (if the electricity is cut, night vision of the eye is already fully functional).

A bit more detail: the rods in our eyes responsible for night vision need ~45 mins of darkness for full adaptation (though some night vision is achieved after a few minutes already). Light disrupts this adaptation - but not red light! So with only red light on, both the night-vision rods and the red-sensitive cones are active the same time.

Source: https://en.wikipedia.org/wiki/Night_vision#Biological_night_...

Have a look at f.lux, which alters your display's colour temperature as the time of day changes, shifting away from blues into the evening.

Flux and night shift modes only reduce blue light, but they don't eliminate it, unless you have an OLED display. Backlights on LCD have tons of blue light that can't be reduced without a physical filter.

Ubuntu 18.04 has a night mode built into the gnome shell. It works really well, allowing a complete removal of blue.

But neither of these has any point if you have blue light bleeding through from the LED backlight of the LCD screen. The most complete solution is OLED and a screen temperature adjustment like this.

macOS and iOS also have Night Shift these days which is the same feature baked in.

Windows also has had this for a little while. I don't know if it's a default in Android.

Modern android has a "night mode" that you can configure to turn on after a certain time of day that cuts the blue light.

LineageOS has it, do not know about stock.

Windows Night Light

Doesn’t go as far. Colour filters in ios accessibility do more.

I feel like Apple really dropped the ball on that. Neither of the two reverse video modes remove blue. Flux works great on OSX and the people that make it really care about low-light accessibility, I'm typing this on my Dark Mode MacBook that I bought specifically to live at my bedside. Nothing else compares.

iPhone's accessibility page for color filters looks like a clown car show of useless features. If anyone's found the magic configuration that makes that shitshow usable please share it.

What I've found is:

1. You can set "reduce white point" to reduce white light 2. You can set a color tint filter and move the hue far to the left. That's the red/orange area. Set intensity to max. 3. You can set the accessibility shortcut to turn these on. (This one is lacking - it slows app switching on non-X devices)

I don't know how to assess actual colour spectrum output, mind you. Does this seem effective?

I leave night shift and true tone on as well.

I think the problem I had with this one is that any time you're looking at something that would be white, instead it's super bright red. Without something that actually changes the displayed colors, you're stuck reducing the contrast so much everything's barely legible. But I'll give it another shot, thanks.

Yeah I actuslly go for a dark orange. The red wasn’t really useable. Reduce whit epoint is actually my favourite part though.

Could you write a bit more in detail about the products you purchased and why?

I have looked myself, but there is a jungle out there and I find it difficult to choose products.

For personal red illumination I use USB-rechargeable NightRider rear bike lights. I ultimately got two and I take them everywhere with me. They are great night lights, especially when travelling, except for the fact they flash blue when you turn them off to indicate their charge level! Using bike lights makes sense as they are designed to be durable, waterproof, and long lived.

I've used a series of OLED screened phones. Rooting can help to ensure you really can put a full screen temperature adjustment on the phone. I regret not having done this on my current phone, which is a oneplus model.

In the past year or two a huge number of multicolor LED lighting solutions [1] have shown up on amazon. These are usually cheap strips of several hundred multicolor LEDs, and come with an IR remote that lets you set one of a number of colors--- among which are pure rend and oranges that are nice in the evening.

[1] For instance: https://www.amazon.com/TOPMAX-16-4ft-Strips-Lighting-Charger...

What laptop has OLED? I thought burn-in would be too bad.

Here are all of them: https://www.oled-info.com/oled-devices/laptops

I dont know what the Macbook is doing on the list, just its touch bar uses OLED

It's no worse than on a phone. I've never noticed burn in on any OLED phone or my current laptop (although the latter is newer).

I'm using a thinkpad X1 yoga OLED. The biggest danger with this device is using Windows, as the drivers for the display panel have a bug in them that will lead to degradation and destruction of the panel. Using Linux avoids this issue.

How can a driver destroy a screen?

Have you come across Philips ChooseScene / SceneSwitch they’re and LED bulb the switches between 2700K and 4500K when switched off and back on.

I have one next to me and it goes below 2000k (1800k I think) in the third setting. Really cool to use as a night reading light.

Yeah I just saw the current model have three settings, will have to get some.