thanks - yes we would love have a UI for something like this - it is too permanent as it is now.

You might look for options > expanded daytime settings.

Yes we thought it was interesting (especially in the winter), that sleep timing dictates how much time you can spend outside when the sun is up. For some people it gets very small in the winter, so we put it in there.

The High Sierra bug has been reported to Apple. Mojave has a fix already. There is a f.lux build posted with a temporary workaround.

Late 2018 Macbook 15" here; tried the build 39.9871 and the defaults write ... commands posted above. It largely works, but there are brief periods (< 5 seconds) where black parts of the screen show as bright cyan / bright blue, and then revert back to black. If it helps, I have the Intel UHD Graphics 630 card on this mac.

Thanks! Here are my responses - sorry for the delay.

Dimming definitely helps in my experience. I only relatively recently started using f.lux so I don't know I've 100% optimized it, but I keep it at almost sunset level the whole day and it seems to help. Not sure - I use a Macbook Pro if that helps. Maybe other people can speak to their experiences (I bet you could find some on the Reddit forum if not here) but morning vs. night isn't really the main difference. The big thing is just: have I overdone it earlier in the day (or even the day before)? Earlier on, when things were worse, my day could be shot after a few hours, so that would make it seem like evenings are worse but they'd only be worse because of the opportunity to screw things up in the morning. Overnight, I partially "reset", but not completely. So anytime after the first few hours of the day is on average worse, but mornings are probably more important all else equal.

An analogy that might help (though it's not exact) is having a headache. You don't want bright lights when you have a headache. Also, at least during the first few days you have problems with filtering light out - everything has glare. I first realized I had a problem when I looked at my e-mail in the morning, sitting at the same distance from my computer as usual, and couldn't read it (due to glare). (Similarly, years ago I had Lasik -- initially I had some small amount of halos/starbursts around streetlights at night, but that went away in a few days as my brain learned to tune it out. After my concussion, I got those halos/starbursts back with a vengeance, as if my brain forgot how to process that. I suspect people also have adapted to using computers over time -- if you went from 0 computer usage ever to 10 hours a day, you might also have a problem until adjusting.)

Thanks again for your good work, and for the questions!

I am hearing this is fixed in Mojave beta 5, but there is a post here that can help if you are on an older version:

https://forum.justgetflux.com/topic/6514/true-tone-mac-introduces-artefacts-when-flux-enabled-fixed-in-beta-5/10

The time of sunset is defined in astronomy as the moment when the upper limb of the Sun disappears below the horizon. Near the horizon, atmospheric refraction causes sunlight rays to be distorted to such an extent that geometrically the solar disk is already about one diameter below the horizon when a sunset is observed.

tried uninstalling manually and it still behaves in this way. any advice or things to try would be appreciated.

I also had flux disabled for fullscreen apps. It's ok now though.

For everyone reading, the profile is a 10-bit calibration table from a Datacolor Spyder.

We are going to add support to our reader for this, but f.lux is ignoring it in the current build.

I usually refresh the wallpaper here.