Monitor Test: Colours, Uniformity and Sharpness
Choose a test pattern, go full screen and inspect your display for backlight bleed, banding, poor black levels and blurry text.
Your display as the browser reports it
A new monitor can arrive with a faint yellow tint on one side, a patch of backlight glowing in a corner, or blacks that are really dark grey. None of that is obvious on a busy desktop full of windows. It becomes obvious the moment you fill the screen with a single color or a carefully designed pattern. This monitor test gives you seventeen of those patterns in one place: solid colors, gradients, black and white level steps, a gamma check, a geometry grid, a fine checkerboard, text sharpness and classic color bars.
Each pattern comes with a short explanation of exactly what to look for, and the whole set can run fullscreen with keyboard navigation. Below the preview, the tool also lists what your browser reports about the display: resolution, scaling, color depth, color gamut and HDR status.
How to use the monitor test
- Choose a pattern from the list, or step through them with the Prev and Next buttons.
- Read the description below the preview so you know what a problem looks like on that pattern.
- Press Fullscreen. The cursor and on-screen label hide automatically after a moment.
- Use the arrow keys, Space or a click to move to the next pattern. Press Escape to exit.
- Check the display information panel to confirm your screen is running at its native resolution and scaling.
For the most accurate results, set your browser zoom to 100 percent, turn off night light or blue light filters, and let the monitor warm up for about fifteen minutes.
What each group of patterns tests
Solid colors
White, black, red, green and blue fill the screen so defective pixels stand out immediately. The mid gray pattern is the best test of uniformity, showing darker corners, blotchy areas or a tint that changes across the panel. The dark gray pattern reveals backlight bleed and IPS glow, which are hard to see on pure black in a lit room. For a dedicated pixel hunt with a repair tool, use the dead pixel test.
Gradients and levels
Gradients should flow smoothly from dark to light. Visible stripes are banding, usually caused by low bit depth or heavy image processing. The gray steps, black level and white level patterns show whether dark and light shades stay distinguishable. If the first few near black blocks merge together, detail in dark game scenes and films is being lost.
Gamma check
Three panels of fine stripes surround solid squares for gamma values of 1.8, 2.2 and 2.4. Step back and squint: the panel where the center blends into the stripes indicates your approximate gamma. Most content is designed for 2.2.
Geometry and sharpness
The grid and circle reveal stretching or distortion from wrong scaling or aspect ratio. The single pixel checkerboard should look like even gray, and shimmering or moire points to scaling problems. The text pattern shows whether small type is crisp. Color bars check that each primary and secondary color is saturated and cleanly separated.
Understanding the display information
| Item | What to check |
|---|---|
| Physical resolution | Should match your monitor’s native resolution |
| Device pixel ratio | Your operating system scaling, such as 100 or 150 percent |
| Color depth | Usually 24 bit, meaning 8 bits per channel |
| Color gamut | sRGB is standard, Display P3 and Rec. 2020 are wide gamut |
| HDR support | Shows whether HDR is currently active in the browser |
If the physical resolution is lower than your monitor’s rated resolution, text and images are being upscaled and will look soft. Set the native resolution in your operating system display settings. Browsers cannot read refresh rate directly, so measure it separately with the refresh rate test.
Common problems and what they mean
- Bright glow in corners on dark gray. Backlight bleed or IPS glow. Some is normal on IPS panels. Strong, patchy bleed visible in normal use is worth a return.
- Stripes in gradients. Check that the graphics driver outputs full 8 bit or 10 bit color, and disable dynamic contrast.
- Merged near black steps. Brightness or black level is too low, or the RGB range is mismatched between limited and full.
- Tinted gray. Uneven color temperature. Try the monitor’s preset modes, or a calibration tool if the tint changes across the screen.
- Blurry text. Usually a non-native resolution or aggressive sharpness settings.
Tips for testing a monitor properly
- Test in the lighting you normally use, then again in a dark room for bleed and glow.
- View the screen straight on at your usual distance. Viewing angle changes color on many panels.
- Reset the monitor to factory settings before judging it, so previous tweaks do not hide problems.
- Test within the return window. Panel defects are much easier to resolve early.
- Photograph serious problems. A camera exaggerates bleed, so compare the photo against what you see.
Your display is also one of the biggest factors in how responsive games feel. After checking image quality, measure your real response with the reaction time test, and if you stream or video call, make sure your camera is up to the same standard with the webcam test.
Frequently asked questions
How do I test my monitor for problems?
Run through the solid colors, gradients and level patterns in fullscreen, reading the description for each. Solid colors reveal pixel faults and uniformity issues, gradients reveal banding, and level steps show crushed blacks or clipped whites.
What is backlight bleed?
Light leaking around the edges of an LCD panel, most visible on dark images in a dark room. Mild bleed is common. Strong patches visible during normal use are a defect.
Why does my monitor show a lower resolution than advertised?
Your operating system may be set to a non-native resolution, or scaling is being applied. Set the native resolution in your display settings for the sharpest image.
Can this test calibrate my monitor?
It helps you adjust brightness, contrast and gamma by eye, but precise color calibration needs a hardware colorimeter.
Does the monitor test work on phones and TVs?
Yes. Any screen with a modern browser can display the patterns, including phones, tablets and smart TVs.
How do I test for backlight bleed?
Show a full black screen in a dark room at medium brightness. Light leaking from the edges or corners is backlight bleed.
What is IPS glow?
A faint glow in the corners of IPS panels when viewed at an angle. It changes as you move your head, unlike backlight bleed.
Should I calibrate my monitor?
For photo or video work, a hardware calibrator gives accurate colours. For everyday use, choosing the sRGB preset is usually enough.
Can this test a TV or laptop screen?
Yes. Any display connected to your device works. Use fullscreen for the most accurate view.
Related tools
Found a suspicious speck? Hunt it down.
Cycle full-screen colors to confirm dead or stuck pixels, then try the built-in fixer before you send the monitor back.