Reposting this from here from 2023, after I stumbled across it tonight and it hits hard.
The text in the image:
I love my smart TV. I love the way it takes a long time to boot up because it’s trying to refresh the advertisements on the home screen. I delight in the way it randomly restarts because it’s downloaded an update without asking me, each of which makes the TV slower and slower with every subsequent install. I adore the way it buries the apps that I want to use, and that I use without fail every single time, below the apps that it’s being paid to promote and which I have never touched in my life and would never use without the cold metal of a glock pressed hard against my sweating temple. I am infinitely thrilled by the way the interface lags constantly, due to the need to have one thousand unnecessary animations rendered on hardware ripped wholesale from a ten year old phone. I feel myself borne aloft on wings of pure joy when I am notified that my data will be collected and analysed to determine my usage patterns. Even now I am writing this from a field of beautiful flowers and soft luscious grass as I lie and look up happily at the bright blue sky, smiling happily to know that this is the future of technology
Maybe the best way to think about it is not dark, but the absence of more light.
On a DMD projector, we use tiny micromirrors for each pixel which flash thousands of times per frame of video.
The flash/no-flash ratio decides how much light makes it out of the projector. This gives us over a thousand light levels per colour channel, from near dark, to full light.
When the mirrors are not in position, the light output is very low. (1/1000th of the full output, on a projector with a static 1000:1 contrast ratio)
The screen is designed to reflect light well, which means in a non-perfect room, it will have a light floor of the reflected ambient light, plus whatever still makes it through the projector (as Cygnus mentioned, room treatment).
If you do treat a room well enough that the small amount of light that makes it through the projector at all-off is a problem, you can do things like fitting an ND filter to the lens (reducing the full light output, while also reducing the minimum).
Or you can use the dynamic iris fitted to some projectors (which reduces the amount of light being put out based on the overall scene illumination, similar to the way LCD TVs lower the backlight level to "reach" contrast ratios of 100000:1).