Red — #FF0000
Red screen.
Pure red. One channel wide open, the other two shut. It exists to find the red subpixel that won't quit.
01 — Panel
The panel
Any hex works. Patterns are drawn in CSS, so nothing blurs when the panel goes fullscreen.
Colour
Pattern
02 — Uses
What this colour is for
- Stuck subpixels
- A red field shows a red subpixel doing nothing, and a green or blue one that's stuck on.
- Uniformity
- Red is where cheap panels show blotches first. Photograph the screen flat-on if you need to argue with a warranty desk.
- Channel by channel
- Red, then green, then blue tests every subpixel individually. That's the whole panel accounted for.
- Keeping night vision
- A dim red screen is the old way to see something without losing dark adaptation. Not a safelight, but closer than white.
03 — Step by step
Testing a screen with it
Full brightness
Subpixel faults are easiest to see bright.
Fill the screen
No window chrome, no dock. Just red.
Sweep it slowly
Left to right, then top to bottom. A stuck subpixel is one pixel wide.
04 — FAQ
FAQ
Why red and not white?
White lights all three subpixels at once, so a dead red and a dead blue both look black. Separate channels separate the faults.
Is a red screen bad for your eyes?
No more than any other saturated colour. It is harder to focus on, which is why it feels loud.