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Distinguish differences between adjacent grey blocks
Grey levels
6-bit Panel
Only 64 levels, uses dithering
8-bit Panel
256 levels, mainstream standard
10-bit Panel
1024 levels, professional grade
Professional Greyscale & Uniformity Testing
No software downloads needed — fully evaluate your display's grey discrimination and backlight uniformity right in the browser.
Four Test Modes
Greyscale patches, shadow detail, highlight detail, and uniformity detection — four complementary test modes, from full range to extreme intervals, comprehensively covering every dimension of panel grey performance.
Adjustable Grey Levels
Continuously adjustable 4-64 grey levels precisely simulate grey discrimination at different panel bit depths. Quickly switch between 17, 32, and 52 level presets for different precision requirements.
Backlight Uniformity
Dedicated uniformity mode with 0-255 full brightness range slider. Observe whether different screen areas exhibit backlight non-uniformity, light leakage, or shadows at various brightness levels.
What Is a Greyscale Test?
Understanding grey discrimination and uniformity testing principles for more meaningful results.
Grey Discrimination
Greyscale tests display multiple grey levels from pure black to pure white, checking whether the panel can clearly distinguish adjacent greys. High-quality panels show clear boundaries between every patch even at 17 or 52 level settings. If adjacent patches "merge" together, that range exceeds the panel's capability.
Shadow & Highlight Detail
The shadow range (0-50) and highlight range (200-255) are where panels are weakest. Entry-level panels frequently lose shadow detail — you see a solid black wall instead of layered dark tones. Professional panels maintain clear level separation even in these extreme ranges.
Backlight Uniformity
Even with excellent grey discrimination, a panel may still have backlight uniformity issues. On a uniform grey background, local brightness differences expose backlight module quality — IPS corner glow, VA center darkening, and OLED mura patterns can all be discovered through this test.
How to Run a Greyscale Test
Three steps to quickly evaluate panel grey performance.
Full Range Check
Use "Greyscale Patches" mode at 17 levels. In fullscreen, observe whether each grey patch is clearly distinguishable from its neighbors. If all 17 levels are visible, the panel's baseline quality is acceptable.
Extreme Range Test
Switch to "Shadow Detail" and "Highlight Detail" modes. Increase to 32 or 52 levels and carefully examine near-black and near-white regions — this is the key range for distinguishing 6-bit, 8-bit, and 10-bit panels.
Uniformity Scan
Switch to "Uniformity" mode and slide brightness to the 30-50 low range. In a dark room, observe whether the screen has locally brighter or darker areas. Then raise brightness to 200+ and check high-brightness uniformity.
Four Test Modes Explained
Full Range Greyscale
Covers the entire 0-255 range, dividing grey evenly into specified levels. Each patch represents a grey level; the brightness difference between adjacent patches depends on the level count — more levels mean smaller differences and harder discrimination. This is the core greyscale test mode.
Shadow Detail
Tests only the 0-50 range (~first 20%), densely packing grey patches in the near-black region. Shadows are where panels are weakest — human eyes are extremely sensitive to dark tone variations, and any quantization artifacts and backlight leakage are exposed here.
Highlight Detail
Tests only the 200-255 range (~last 20%), densely packing grey patches in the near-white region. Lost highlight detail causes white content to appear as a "flat white wash" lacking depth, directly affecting document reading and web browsing comfort.
Uniformity
Displays a single grey value fullscreen with adjustable brightness 0-255. On a constant grey background, panel backlight non-uniformity is fully exposed. Best tested in a dark room, focusing on the four corners and center area for brightness consistency.
Greyscale Performance by Panel Type
Understanding typical grey test behavior of mainstream panel technologies.
IPS Panel
Greyscale Characteristics:
• Average shadow performance — blacks aren't deep enough (~1000:1 contrast).
• Corner glow is the most common uniformity issue.
• Wide viewing angles with consistent greyscale from different positions.
VA Panel
Greyscale Characteristics:
• Shadow detail tends to be "swallowed" — near-black depth is weaker than IPS.
• Noticeable side-view color shift; center and edge grey may be inconsistent.
• In uniformity tests, center-dark + edges-bright is a common pattern.
OLED Panel
Greyscale Characteristics:
• Low-brightness grey may show mura pattern (manufacturing process variation).
• Each pixel is independently lit — no traditional backlight uniformity issues.
• Extended use may cause pixel aging that degrades uniformity over time.
Mini LED Backlight
Greyscale Characteristics:
• Zone boundary grey transitions may not be perfectly smooth (blooming).
• Better uniformity than traditional LED backlight, but not as precise as OLED.
• Excellent greyscale in high-contrast scenes; uniform grey may expose zone boundaries.
How to Interpret Results
All Distinguishable
All 17 grey levels clearly separable, shadow/highlight detail is clear — panel grey performance is excellent, at least native 8-bit quality.
Partial Merging
2-3 adjacent patch pairs in shadow or highlight ranges are indistinguishable — may be a 6-bit+FRC panel, or the monitor's color calibration has drifted.
Major Loss
More than 1/3 of patches are indistinguishable — panel bit depth is severely insufficient or gamma setting is significantly off. Adjust monitor settings.
Uniformity Variance
Some areas are noticeably brighter or darker — backlight non-uniformity. Minor differences are normal; obvious block differences warrant contacting support.
Frequently Asked Questions
Q.What's the difference between greyscale and color banding tests?
Greyscale tests evaluate how many grey levels a panel can distinguish (discrimination) using discrete patches; color banding tests check for bands in continuous gradients (smoothness). They're complementary: greyscale tests better assess raw panel performance, while banding tests closer simulate real viewing.
Q.Why can't I see shadow differences?
Possible causes: 1) Insufficient panel bit depth (6-bit); 2) Monitor brightness set too low; 3) Ambient light interference; 4) Gamma curve offset. Test in a dark room at 50-70% brightness with gamma confirmed at 2.2.
Q.Should I use 17 or 52 levels?
17 levels is baseline — if you can't distinguish all 17, the panel's grey capability is clearly insufficient. 52 levels is advanced — it challenges even 8-bit panels, used to assess professional-grade performance.
Q.Can uniformity issues be fixed?
Backlight non-uniformity is a hardware issue that can't be fixed via software. Some high-end monitors support "uniformity compensation" that reduces bright areas to match dark areas, at the cost of maximum brightness. Severe non-uniformity should be reported under warranty.
Q.Should I test laptop screens?
Definitely. Laptop screen quality varies enormously — many entry-level laptops use 6-bit TN/IPS panels with poor shadow greyscale. If you use your laptop for design or video editing, greyscale testing reveals the screen's true capabilities.
Q.Why do grey patches look different at different angles?
This is determined by panel viewing angle characteristics. TN panels are worst — looking down washes out, looking up darkens. VA panels shift colors from the side. IPS is relatively consistent but may yellow at corners. OLED has the best viewing angles. Test while facing the screen center at normal distance.
Greyscale Testing Environment Tips
- • Ambient Lighting: Turn off indoor lights and close curtains. Testing in a dark room yields the best results. Ambient light reduces shadow grey discrimination.
- • Monitor Warm-Up: Wait at least 15-20 minutes after power-on before testing. Panel brightness and color may be unstable when cold.
- • Brightness Setting: Set monitor brightness to 40-70%. Too low loses shadow detail; too high loses highlight detail.
- • Gamma Check: Ensure system gamma is set to 2.2 (Windows/macOS default). Incorrect gamma causes uneven grey distribution.