Add option to use Night Light all day

[ryonakano]

It seems that there is no way to use Night Light all day. If I set manually "from 0:00 to 23:59" at System Setting→Display→Night Light→Schedule, the setting changed "from 0:00 to 23:00" forcibly, and it was disabled from 23:00 to 0:00.

[syvanpera]

I took a look at this. I suppose this needs to be implemented int 'switchboard-plug-display'. I already made a quick POC and it seems simple enough to add this option as a third option to the Schedule selector. Unfortunately the schedule is currently stored as a boolean value so it would need to be changed and that would make it incompatible with current implementation. Or am I way off base here? First time looking for a place where I could contribute

[janxkoci]

One question - why? There is no medical benefit from having night light applied during the daylight.

Edit: If you live beyond the polar circle, there should be a better way to do this.

[ryonakano]

@janxkoci Oh, I didn't know that here is no medical benefit from having night light applied during the daylight. I believed it would prevent my eyesight from getting worse by setting night light whenever I use my computer… 😅

BTW I live in Japan, which is not beyond the polar circle.

[ryonakano]

So should I close this issue because there would be no enough reason to allow users to set Night Light all the day?

Edit: It seems other OSes like macOS, iOS, or Windows 10 also does not have this option.

[janxkoci]

The purpose of Night light and similar technologies is to help with eye strain during the evening and night hours (when both natural and artificial light are more redshifted compared to daylight) and to reduce negative effects of computer use on your sleep cycle. This is generally done by filtering out blue light by redshifting your screen colour output, as blue light (typical for daylight) affects the production of hormone melatonin in your pineal gland, which is responsible for your sleep cycles.

There are some studies on other effects of blue light on the eyes' health, but AFAIK the research is not conclusive - for now we know Night light helps with eye strain during evening and night hours and with sleep cycles. Other benefits are debatable.

[alexbainter]

Workaround:
Night Light will "wrap around" days, meaning you can set a "From" time that's after "To." The only catch is that for some reason there must be more than an hour between "To" and "From" -- otherwise Night Light won't turn on. This means you can have Night Light on for 23 hours per day.

For example, I have my Night Light scheduled from 4:31 AM to 3:30 AM, so it's only off from 3:30 AM to 4:31 AM (when I'm almost certainly not on my computer).

Side note: this is the same trick I use with macOS's "Night Shift," except that only requires a 1-minute gap.

[jeremypw]

There should be a separate "base level" setting for color temperature of the display that applies all the time. The night-light scale should then range between the base level and max warmth.

[panicsteve]

Just adding a little +1 to this request. I'm not looking for any particular "medical benefit", it's just that my laptop's panel can be pretty harsh even during the daytime and changing the color temperature a bit makes staring at it more pleasant.

I guess what I actually want is a color temperature control for the display, rather than "all-day Night Light" per se, but it was the closest setting I could find. :)

[jeremypw]

A quick look indicates there is no simple way of setting the base color temperature of the display (except using any hardware controls the display has). There is only a setting for the nightlight temperature in the dconf schemas. :-( I tried RedShift but it did not run on Elementary Hera

[jeremypw]

I tried using the terminal app scm (in AppCenter) and this worked for a few seconds but then the color reverted even if I killed the gnome daemons dealing with color and turned off the nightlight so something else is controlling the screen color-temperature - not sure what.

[janxkoci]

My two cents:

1. Have you tried calibrating your display, @panicsteve? I've never done it but sounds like this would be its use case. Else you could try an app like Redshift.
2. Redshift works fine from the terminal @jeremypw, it's just the indicator is gone. I had some interference in Gnome and had to switch the nightlight off there, maybe good idea in elementary too.