Factorio Forums

The patch-notes for 0.16.0 listed this:
Added support to change daytime length and brightness on a per-surface basis.
The LUA API does not list any way of achieving this. However, this can be somewhat simulated by setting surface.dusk to values above 1.0 and surface.dawn to values below 0.0. This feels like a hack that shouldn't be used, even if it works. The following values will create the brightest 'eternal night' without freezing time, and allowing the solar-panels to generate power while the lights never go off:

/c game.player.surface.dusk = -1.1667
/c game.player.surface.evening = 0.5
/c game.player.surface.morning = 0.5001
/c game.player.surface.dawn = 2.1667

http://lua-api.factorio.com/0.16.20/Classes.html Contains all other settings related to the day-night cycle, except setting the brighness/darkness of the day/night.

Thanks for the report. Brightness is calculated based off the dusk, dawn, evening and morning properties. There is no direct property to set.

Then what does the line in the patchnotes mean?
Added support to change daytime [...] brightness on a per-surface basis.

I removed it from the changelog for 0.16.21