In my last post I said Black Light is working well with Night Shift. It appears that I overlooked something however. With some hardware configurations, the Invert Screen filter of Black Light no longer works except when Night Shift is active. This bug appeared in macOS 10.12.4 so it’s probably linked to some changes that were made in macOS in order to make Night Shift possible. That said, it also affects some models that do not support Night Shift.
If your computer is affected by this and it supports Night Shift, there is a workaround: manually activate Night Shift while Black Light inverts your screen. To minimize the color changes of Night Shift, set it to its lowest color temperature setting in System Preferences. If your Mac does not support Night Shift and you already upgraded to 10.12.4, you are out of luck. Sorry.
I filled a bug report with Apple (31521584) about how some gamma curves are ignored by the system and I’m now waiting a reply. Hopefully this will get fixed in the 10.12.5 update, but this remains uncertain at this time.