Screen Contrast TestContrast Test
Choose a pattern and check that you can tell each grey step apart.
Contrast patterns
Tap or press → for the next pattern
How to read it
- Black levels: you should see most squares 1-20.
- White levels: 235-254 should differ from 255.
- Gradient: smooth, without bands.
Tips
- Reset brightness and contrast to defaults.
- Turn off night mode or blue-light filters.
Shortcuts
- Click pattern: fullscreen
- ←→ / click: next pattern
- Esc exit
How to use
- Pick Grey steps, Black levels, White levels or Gradient.
- Tap the pattern or Fullscreen pattern for a bigger view.
- Squares you cannot see, or visible bands, point to contrast or calibration limits.
How to use the screen contrast test
The screen contrast test shows four patterns. Grey steps show 16 even shades from black to white. Black levels show squares from 1 to 20 on pure black; white levels show 254 down to 235 on pure white. Gradients show smooth black-to-white and colour ramps.
Adjusting brightness and contrast
- Raise brightness until the low black-level squares are just visible, without black turning grey.
- Lower contrast if the bright white-level squares merge into white.
- Check gradients for steps or colour tints.
Related checks
Use the backlight bleed test for edge glow and the dead pixel test for faulty pixels.
Frequently asked questions
How many black-level squares should I see?
On a well-set monitor you should be able to tell most squares from 1 to 20 apart from pure black in a dim room. If several low numbers merge into black, raise brightness or check the black level setting.
Why does my gradient show bands?
Banding can come from 6-bit or 8-bit panels, colour profiles, low-quality cables or video settings. Some banding is normal in browsers.
Does the contrast test measure contrast ratio?
No. A web page cannot measure light output. It shows patterns so you can judge shadow and highlight detail by eye.