Screen Color Test Guide
This screen color test guide uses the same basic idea every time: fill the screen with one solid color and look closely. What's simple gets more useful once you know what each color is actually good at revealing, and in what order to check them.
What each color reveals
| Color | Best for spotting |
|---|---|
| White | Dark spots (dead pixels), dust, smudges, general brightness evenness |
| Black | Backlight bleed, IPS glow, stuck (colored) pixels, OLED uniformity |
| Red | Red sub-pixel stuck/dead status, color banding |
| Green | Green sub-pixel stuck/dead status. Often the easiest color to spot defects in, since the eye is most sensitive to green |
| Blue | Blue sub-pixel stuck/dead status, subtle backlight tinting |
The right order to test in
- Start with white for an overall first pass and to catch dead pixels.
- Switch to black to check for stuck pixels and backlight uniformity.
- Cycle through red, green, and blue. The Dead Pixel Test tool's auto-cycle feature does this for you automatically.
- Finish with the Touch Screen Test. A display can look perfect and still have a dead touch zone, which only shows up under direct interaction, not a color scan.
- If you find anything, note its position and re-check it against at least two different colors to confirm it's a genuine, consistent defect and not a trick of the light.
Conditions that make testing more reliable
- Darken the room, since most defects are far easier to see with less ambient light competing with the screen.
- Use your screen's native resolution and turn off any adaptive brightness, HDR, or dynamic contrast modes.
- Sit at a normal, comfortable viewing distance rather than pressing close to the panel.
- Clean the screen first, since a smudge or speck of dust is easy to mistake for a pixel defect.
Where to go from here
If you're testing a brand-new display, our new monitor defect checklist walks through what to do with whatever you find. If you spot brightening on a black screen specifically, the screen uniformity guide covers how to tell a normal panel characteristic from an actual defect.
Frequently asked questions
Do I need special equipment to test my screen?
How often should I test my screen?
Open the Dead Pixel Test tool →
Sources & further reading
Cedrick Reese wrote this guide. The color-by-color notes follow how screens build every color from red, green, and blue subpixels, and the point about green being easiest for spotting defects rests on the eye's peak sensitivity to green light, cited under Sources. Each color links to the tool on this site that displays it. Sources were checked in September 2026.
About the author
WhitestScreen.com was founded by Cedrick Reese, a retired veteran and web developer who enjoys building free, user-friendly online tools that simplify everyday tasks. More about Cedrick Reese →