What a maroon screen is used for
- Very low ambient light that preserves night vision better than white
- Deep, rich backgrounds for photography
- Checking red channel behaviour at mid output rather than maximum
Maroon screen online: #800000 at full screen
Maroon is #800000 — red at half, green and blue at zero. Because it is both red and dark, it is the gentlest way to have a screen visibly on in a dark room without wrecking dark adaptation. Astronomers and darkroom workers reach for red for exactly this reason, and maroon is red with the brightness already taken out.
It is also a more useful red-channel test than full red for one specific thing: mid-tone banding. Full red saturates; half red sits where an 8-bit panel with a poor gamma curve will show stepping if it is going to show it anywhere.
With green and blue at zero, any non-red content in this field is a subpixel fault.
How to get a full screen maroon background
Press the fullscreen button on the player above, or the F key. Escape returns you to the page. On a desktop browser F11 does the same job and hides the browser's own toolbars as well.
The colour box is a control, not a picture: use the hex field to enter any value, pick another shade from the palette, or download the current colour as a PNG at your screen's resolution. Whatever you set is written into the address bar, so the link you copy reproduces exactly what you are looking at.