async Finally something that feels like messing with color profiles. Seems somewhat better.
Yep, seems like it generally improves OLED iPhones, mostly because it disables HDR which is usually always-on on OLED iPhones even in the system UI (for example, Control Center volume sliders and the clock on iOS16+ lockscreen both use "brighter than white" shades of white, and double inverting is able to stop this)
Also, it finally lets me fix the super bright HDR white used in the screenshot flash that always feels like it's blinding me if I take a screenshot in a dark room. BTW, "Reduce Transparency" also disables the HDR white in specifically the screenshot flash (but not anywhere else). But with double invert I can keep transparent backgrounds on if I want while still disabling HDR here and in other places too.
It still seems like the one device it had the most noticeable and significant effect on is the 2018 iPad Pro. I was actually super shocked when I first tried it (I discovered the technique while messing around with the settings on that device) because on specifically the 2018 iPad Pro it seems to stop the "false 3D" effect in tons of places. Also, very wide or very long elements in the UI, like the search bar in Google Drive in landscape mode, become a lot easier to see all at once instead of only being able to focus in on a small segment of it. This was on iOS 17.1 I think.
Unfortunately on newer LCD devices like SE 2020 it doesn't have the same effects, SE 2020 has one of the worst "false 3D" effects I've seen on an iPhone even on stuff like the home screen icons against the wallpaper, and double invert doesn't change it. I've been only been able to get as many changes as that on the 2018 iPad Pro.