UtilityBaseScreen Tools
Blue Screen
Fill your display with solid blue to test the blue subpixels.
Updated January 6, 2026
How to use the blue screen
- 1Click the color area or the fullscreen button to enter fullscreen.
- 2Move the mouse or tap the screen to show or hide the toolbar.
- 3Use the brightness slider to dim the color if it is too intense.
- 4Press Esc or the exit button to leave fullscreen.
Common uses
- Isolate faulty blue subpixels during pixel testing.
- Spot dust and smudges on glossy displays.
- Complete a full RGB panel inspection with the red and green screens.
Frequently asked questions
How do I make my whole screen blue?
Open the tool and press the fullscreen button (or the F key). The entire display turns blue. Press Esc or F again to exit fullscreen.
Can I adjust the brightness?
Yes. Use the brightness slider in the toolbar to dim the screen without changing your system settings. This is a software dimmer applied on top of the color.
Will my screen turn off while the color is displayed?
The tool requests a screen wake lock in browsers that support it, which prevents the display from sleeping while the tool is active. If your browser doesn't support wake locks, adjust your system sleep settings for long sessions.
Does this work on phones and tablets?
Yes. On mobile, tap the fullscreen button to hide the browser interface where the platform allows it. Tap anywhere on the screen to bring the controls back.
About this tool
The blue screen tool renders pure blue (#0000FF) across the whole display, activating only the blue subpixels. It completes the red–green–blue cycle used to isolate stuck and dead subpixels: a dark dot on the blue field means a dead blue subpixel at that location. Blue fields also make dust and fingerprints easy to see on glossy panels, and some photographers use them to check a monitor's color cast.
Like everything on UtilityBase, the blue screen runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more screen tools here.
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