Tool
Screen Test
Test dead pixels, bleed, and gradients — or dim the room with a black screen.
Full-screen solids find dead pixels. Black also works as a night cover. Grids, contrast ramps, and gradients check bleed, stability, and banding.
Preview — click to open full screen
Dead-pixel colors
Interference
Focus & geometry
Contrast & color
Full-screen shortcuts: ← previous, → next, Esc exit, H or Space toggle the bar, 1–8 pick a solid. Click the sides or use the wheel to change tests. Click the center for the full bar. Set zoom to 100%.
How to use
Pick a solid color or a test pattern, then open it full screen. For dead pixels, inspect black, white, red, green, and blue. Black also shows backlight bleed; white shows brightness uniformity. Line and dot fields check stability, grids check geometry, contrast patches and gradients check banding. Click the left or right edge to change tests without covering the panel. Click the center for the full bar. Set browser zoom to 100%.
Keyboard shortcuts in full screen: Left Arrow previous test, Right Arrow next test, Esc exit, H or Space toggle the control bar, 1–8 pick a solid color. The scroll wheel also changes tests.
FAQ
- How do I find dead pixels?
- Open a solid color full screen and check each primary. A dead pixel stays black on bright colors. A stuck pixel stays red, green, or blue on a black or opposite-color field.
- What are the extra patterns for?
- 1px/2px lines and dots show interference. Focus marks and grids show sharpness and geometry. Near-white and near-black patches test contrast. Gradients and the saturation grid show banding and hue separation.
- Can this make the screen darker than the system brightness?
- No. It cannot change backlight or OLED system brightness. A black full screen is still the darkest image the page can show, which helps at night especially on OLED.
- What are the keyboard shortcuts?
- In full screen: Left Arrow previous test, Right Arrow next test, Esc exit, H or Space toggle the control bar, 1–8 pick a solid color. You can also click the left or right edge, or use the scroll wheel, to change tests. Click the center for the full bar.
- How do I leave full screen?
- Press Esc, or show the controls and click Exit. Click the left or right edge to change tests. Click the center, or press H / Space, for the full bar.