Colour Banding Test
Colour Banding Test sweeps a smooth gradient across your entire screen so you can watch for visible stepping — hard bands instead of a smooth blend — in the transition. Click Start Colour Banding Test to cycle through a black-to-white sweep and a couple of subtler tonal gradients, keeping in mind that your browser itself dithers CSS gradients, so this is a visual approximation rather than a lab-grade banding measurement; still, obvious hard bands you can see are a genuine sign of low color-depth rendering. The run a touch screen test is free and runs entirely client-side, so nothing about your display is ever uploaded.
Click Start Colour Banding Test to cycle through gradient patterns. Look closely for hard visible steps instead of a smooth blend — that's banding. Your browser dithers CSS gradients, so treat this as a visual check rather than a precise measurement. Use the arrow keys or on-screen controls to move to the next pattern, and Escape to exit.
Ever watched a dark movie scene and noticed that the sky — instead of fading smoothly from deep black to a soft midnight blue — breaks into visible steps that look like a topographic map? That jarring effect is colour banding, and running a colour banding test on your screen reveals exactly how well your display handles the trickiest transitions in any image. The result tells you something actionable: whether your setup, cable, driver, or source content is quietly robbing you of shadow detail, gradient smoothness, and true image quality.
What Is Colour Banding and Why Does This Colour Banding Test Matter?
Colour banding is what happens when a screen cannot reproduce enough distinct shades between two tones to make a transition look continuous. Instead of a silky ramp from one brightness level to the next, you see abrupt colour steps — visible color stripes — with hard contour edges between them. Think of a clear evening sky that should fade seamlessly from pale blue at the horizon to deep indigo overhead, but instead shows three or four blunt rings of colour, each separated by a noticeable jump. Those are the distinguishable bands that a properly configured screen should never produce. Use the color accuracy test online to confirm whether your monitor shows this issue before you adjust settings or return it.
A properly configured setup reproduces the widest possible range of colors in a smooth color gradient made up of color stripes sharing the same color temperature, where each adjacent stripe has a similar color increment from one to the next. When a misconfigured or malfunctioning unit is in the signal chain, you may see color shift regions along the neutral gradient and uneven different color steps that make the image look posterised.
How Colour Depth Creates or Eliminates a Smooth Gradient
The single biggest cause of colour banding is insufficient tonal precision — the number of discrete levels your screen can reproduce per colour channel. An 8-bit screen encodes each of the red green blue channels with 256 levels, giving a theoretical 16.7 million colors in total. That sounds large, but in long, shallow gradients — especially in shadow tones — 256 steps can still produce visible jumps. A 10-bit screen raises the per-channel count to 1,024 steps, and a higher-precision pipeline reaches 4,096 levels per channel. The difference in gradient smoothness is immediately visible on test patterns and equally visible in real content: skies, skin tones, and shadow gradients all benefit from higher color depth.
The table below summarises the practical impact of each tonal precision level on gradient handling and where each format is most commonly encountered.
| Bit Depth | Levels Per Channel | Gradient Smoothness | Typical Use Case |
|---|---|---|---|
| 8-bit (24-bit color / Truecolor / millions of colors) | 256 grayscale steps | Smooth for most content; color banding possible in long dark gradients | Consumer LCD screen, entry gaming units, standard SDR video |
| 10-bit (30-bit color) | 1024 grayscale steps | Excellent; near-black transitions are clean, onion ring bands rare | Professional screens, high dynamic range gaming units, native 10-bit OLED |
| 12-bit (36-bit color) | 4,096 per channel | Near-imperceptible banding even in the most extreme high-dynamic-range gradient | Broadcast mastering, high-end reference screens, source mastering pipelines |
| 16-bit color (Highcolor / thousands of colors) | 32–64 per channel | Poor; 32 bands or more clearly visible — almost certainly a graphics card settings issue | Legacy systems, incorrect operating system color coordinates settings |
8-bit vs 10-bit vs 12-bit: What the Difference Means for Real-World Gradients
The 8-bit vs 10-bit comparison is most visible in content that contains long, smooth tonal ramps: clear skies, gradual lighting transitions in cinematic scenes, and high-dynamic-range highlight roll-offs. On an 8-bit path, you are limited to up to 256 grayscale steps, so colour banding appears sooner and more severely when the gradient stretches across a wide area. A native 10-bit screen maps the same ramp across up to 1024 grayscale steps, dramatically reducing contour lines and giving shadow tones room to breathe before clipping into a dark background.
For media production and video editing workflows, tonal precision differences between your screen and your source material can cause you to miss banding in your deliverables. A screen with full color depth in the 10-bit range lets you catch gradient contouring in shadow regions that an 8-bit unit simply blends away through dithering or FRC approximation. For competitive gaming, the advantage is subtler but real: a 10-bit screen renders dark scenes with more visible separation between near-black shades, which can reveal hidden enemies in dimly lit corridors that a lesser screen would crush to an indistinguishable black.
Colour Banding in Streaming vs Local Content
Online video banding and local content banding behave very differently, and your grayscale gradient test results can help you identify which is the culprit. When you watch video via a browser, the H.264 or H.265 compression codec aggressively reduces the effective tonal range of shadow transitions to save bandwidth. Compression artifacts introduced at encode time are baked into the stream — your screen cannot recover information that was discarded upstream. The result is visible colour bands even on a native 10-bit screen that handles local files flawlessly.
By contrast, a local 10-bit file with high dynamic range played back through a capable media player during video playback preserves every level of the original grade. The same dark sky scene that shows onion ring bands during browser video playback may be completely smooth when loaded from a local file. This distinction matters: if your grayscale gradient test shows banding only in online content, the source path — not your screen — is the bottleneck. If banding persists with high-quality local files as well, your signal chain (GPU color output, cable port, operating system output depth, or screen tuning) is the place to investigate.
Why You May See Banding on a Technically Good Screen
Even a high-quality 10-bit screen can exhibit visible color bands if any link in the signal chain restricts color depth. The most common causes include: the cable and port not supporting full color depth (you need HDMI 2.0, HDMI 2.1, or DP 1.4 for 10-bit signals with high dynamic range); the GPU falling back to reduced output depth in its driver settings; the operating system color coordinates forcing 8-bit output; high dynamic range being left active during SDR testing (keep HDR off during a standard grayscale banding test — SDR gamma is the correct baseline); or the graphics card settings being misconfigured after a driver update. A faulty graphics card or graphics card limitation at the driver level can produce greenish bands or 32 bands of colour that look exactly like the 16-bit color rendering associated with legacy Highcolor mode.
Run a Colour Banding Test: Gradient Smoothness and Shadow Detail Diagnostic
How to Run the Online Screen Test — Neutral Scale and Colour Channels
The online screen testing tool above is a free screen test designed to surface banding and crush without requiring any software installation. For accurate results, follow this preparation checklist before you begin:
- Set the correct viewing environment: Use a dark room and normal daily brightness. Do not boost your screen brightness to maximum — maximum brightness can artificially lift near-black shades, making low-end separation appear better than it really is under typical conditions.
- Disable HDR: Keep high dynamic range off in both your operating system output settings and screen OSD. SDR gamma is the correct reference for this test.
- Verify your cable and port: Confirm that the cable and port combination supports full color depth. HDMI 2.0, HDMI 2.1, and DP 1.4 all support 10-bit output; older connections may limit the signal chain to 8-bit.
- Check GPU and OS output depth: In your GPU control panel, confirm the output color depth matches your screen's native precision and that the graphics card is not falling back to 6-bit.
- Open the tool in full-screen mode: Switch the browser to full-screen mode to remove UI chrome that can distort your perception of the gradient edges.
- Run the neutral scale first, then the colour gradient channels: Start with the greyscale gradient (the neutral gradient ramp from deep black to bright white), then test each of the red, green, and blue gradient channels separately.
- Use stress test levels: Start with 256 levels for a standard 8-bit assessment, then step down to 128 levels or 32 levels to stress the signal chain further. If lower-count ramps stay clean but 256 shows contouring, the source path or operating system output depth is likely the bottleneck rather than the screen itself.
The sample gradients in the tool display color stripes that share the same color temperature within each channel, with each adjacent stripe having a similar color increment. Run each channel as a separate dynamic range test to isolate any channel-specific imbalances that could affect your color profile or color balance downstream.
Reading Shadow Detail and Dark Tone Color Gradients — Pass and Fail Indicators
The table below describes what a passing and failing result looks like for each gradient channel in this screen test.
| Gradient Channel | Pass (Good Result) | Fail (Problem Detected) |
|---|---|---|
| Neutral (greyscale gradient) | Completely smooth transition from deep black to bright white; no color stripes or bands visible; all shadow tones distinct from the dark background | Visible bands or contour lines in mid-to-dark range; darker gradient region merges into the background (shadow crushing / shadow clipping) |
| Red | Smooth ramp from black through dark red to saturated red; no posterisation; adjacent stripes show similar color increment | Hard edges between colour steps; red channel shows uneven different color steps or color shift at dark end |
| Green | Smooth green gradient with consistent color accuracy across the full range; no banding in shadow tones | Visible bands or greenish bands in darker region; dark-scene detail lost below a certain luminance threshold |
| Blue | Even blue ramp; near-black transitions clean; dark detail retained throughout 0%–10% range | Blue channel posterises in shadows; color steps become distinguishable bands; missing shadow detail in near-black zone |
When you inspect the 0%–10% black grid section of the test, look for hidden numbers embedded in the darkest squares. If the blocks at 0%–4% become indistinguishable from the surrounding background, shadow crushing is present. A well-calibrated screen should resolve every number clearly in a dark room at a comfortable working brightness — not at maximum brightness, which would wash out the shadow detail visibility check.
Worked example — failing result: Imagine an 8-bit VA screen playing back a night-sky scene from a film. The sky behind the stars should fade through dozens of near-black shades. Instead, you see four or five flat zones separated by visible steps — textbook colour banding. Running the neutral scale confirms the problem: the shadow tones collapse into three or four hard bands rather than a continuous greyscale ramp. A 10-bit screen running the same gradient shows a flawless smooth color gradient with no contour lines anywhere along the ramp — the extra grayscale steps fill in the gaps that the 8-bit path leaves behind.
Worked example — streaming vs local: Load a dark sunset scene from a compressed online service in your browser. The sky shows clear banding — onion ring bands arcing across the gradient. Switch to a local high-dynamic-range file of the same scene played through a hardware-accelerated media player. The banding disappears entirely. Same screen, same settings — the difference is compression artifacts in the encoded stream versus the full color depth preserved in the local file. This confirms that local content banding and streaming banding are independent problems, and a single dynamic range test cannot distinguish between them without testing both sources.
Native 10-bit Precision and What a Good Gradient Looks Like on a 10-bit Screen
A native 10-bit screen — whether an LCD unit, a factory-calibrated professional display, or an OLED with per-pixel luminance control — should produce a grayscale gradient test result that looks like a continuous airbrushed ramp from one end to the other. There should be no banded lines or color shift anywhere along the neutral scale, no static or moving patterns in the darker parts, and no noise of the kind that TFT screens with heavy dithering can produce.
OLED technology adds a further advantage: because each element is independently lit, true black is absolute, and the contrast ratio is effectively infinite. This gives OLED screens the cleanest near-black transitions of any screen technology, making this tool both more demanding (there is nowhere for imprecision to hide) and more rewarding — a well-performing OLED delivers infinite contrast alongside smoothness that no backlit LCD can fully match. Mini LED screens occupy a middle ground, using localised dimming zones to approach OLED's shadow rendering while retaining the brightness ceiling of an LCD backlight.
A high-dynamic-range gradient on a capable OLED or Mini LED screen should show per-pixel luminance gradation that looks identical to the 10-bit reference ramp — thousands of shades flowing seamlessly from black through every shade to peak white, with no shadow grid posterisation and no clipping at either end.
Black Crush: Definition, Causes, and Fixes Using the Black Equalizer and Brightness Settings
Black crush occurs when the darkest tones in an image — the 0%–4% luminance range — are clipped together and rendered as identical, indistinguishable blacks. The result is missing shadow detail: textures, depth, and information that exist in the source material simply disappear. In practical terms, this means dark scenes in games or films lose depth — caves look flat, night scenes lose atmosphere, and in competitive shooters, enemy models hidden in shadows become invisible.
Shadow clipping can come from several sources in the signal chain:
- Gamma tuning: An aggressive gamma curve (gamma too high) accelerates the roll-off into black, causing shadow clipping. Gamma calibration in your screen's OSD or GPU colour settings can recover lost dark detail.
- Limited range output: If your GPU is outputting a limited range (16–235) signal but your screen or TV expects full range (0–255), the 0%–16% region is clipped. Correct this in your GPU's output configuration or the screen's input range setting.
- HDR mismatch: Enabling high dynamic range in the operating system while the screen is not properly configured for tone mapping can compress the shadow range and cause near-black transitions to clip.
- Screen brightness set too high: Paradoxically, excessive screen brightness can cause the unit's black point to lift and its dark-tone rendering to become inconsistent, particularly on VA-type screens with their characteristic shadow crushing in corners.
Worked example — shadow clipping fix: A user sets their gaming screen to maximum brightness for daytime use and forgets to reduce it for evening sessions. During the shadow detail portion of the banding test, the 0%–4% blocks are completely invisible — shadow clipping is confirmed. The fix: reduce screen brightness to a comfortable working level, then activate the black equalizer feature in the screen's OSD. The black equalizer lifts the dark-scene detail by brightening near-black tones selectively without washing out the rest of the image. Re-running the test after these adjustments reveals the hidden numbers in all squares from 2% upward, confirming that shadow detail visibility has been restored without sacrificing contrast in brighter areas.
Run Additional Display Diagnostics After Your Online Test
After you complete the grayscale gradient test and shadow detail evaluation, the following related diagnostics give you a comprehensive picture of your screen's overall performance. Each test targets a different dimension of image quality and complements the banding test results you have already gathered. The color temperature test is free and runs entirely client-side, so nothing about your display is ever uploaded.
Dead Pixel Checker — Spot Missing or Stuck Pixels
A dead pixel checker fills your screen with solid primary and secondary colours to make stuck, dead, or hot pixels immediately visible against a flat background. Defective pixels are distinct from banding — they represent a hardware fault at the individual element or sub-element level rather than a colour depth or gamma issue. Running a dead pixel check immediately after your banding evaluation is good practice, particularly on a new screen or laptop. If your screen passes the banding test but shows a dead pixel cluster, you have two separate issues requiring different remedies.
Backlight Bleed Test — Relevance to Shadow Detail and Dark Scenes
A backlight bleed test uses a full black screen to reveal light leaking around the edges or corners of an LCD screen's backlight. Backlight bleed directly affects your perception of dark scenes: a screen with heavy bleed will appear to perform better on shadow detail tests in lit rooms but far worse in the dark room conditions recommended for accurate testing. On an OLED screen, there is no backlight to bleed, but you may encounter other uniformity issues. Identifying backlight bleed separately from banding helps you distinguish screen uniformity problems from colour depth limitations.
Motion Clarity Test — FPS Dark Scenes and Competitive Gaming Performance
A motion clarity test evaluates how cleanly your screen renders fast-moving objects, which is particularly relevant in FPS dark scenes during competitive gaming. Shadow transitions that look clean in a static gradient test can still smear or ghost during motion on screens with slow pixel response or poorly tuned overdrive settings. Competitive shooters rely on both clean shadow detail and sharp motion rendering — combining the banding test results with a motion clarity assessment gives you the full picture of your gaming screen's dark-scene performance. Screen technology plays a major role here: VA-type screens typically offer deeper blacks but slower pixel transitions, while TN-type screens have the fastest response but the narrowest off-axis consistency and weakest colour reproduction. IPS-type screens balance response, colour accuracy, and off-axis performance, while OLED leads in both contrast and pixel response.
Screen Viewing Angles: IPS vs VA vs TN vs OLED — Impact on Gradient and Colour Banding Visibility
Your viewing angle relative to the screen can make colour banding appear worse or better than it actually is — a critical variable when interpreting your grayscale gradient test results. Screen technology determines how dramatically the image shifts as you move off-axis:
- IPS (In-Plane Switching): Wide viewing angles with minimal color shift off-axis; gradients look consistent across the screen, making banding easier to evaluate accurately from a natural seated position. Preferred for media production, video editing, and screen calibration work.
- VA (Vertical Alignment): Higher native contrast and deeper blacks than IPS, but noticeable color shift and gamma shift off-axis. VA-type screens are prone to shadow crushing near the corners, which can produce false positives in a shadow detail workflow if you evaluate corner regions from a straight-on position.
- TN (Twisted Nematic): Fastest response and lowest input lag, but the narrowest off-axis consistency of any LCD technology. Colour and brightness shift dramatically even at modest vertical angles, making TN screens difficult to calibrate accurately for gradient evaluation.
- OLED: Near-perfect viewing angles with virtually no color shift off-axis; per-pixel luminance control eliminates backlight uniformity issues entirely. OLED delivers the most faithful shadow grid rendering and the cleanest shadow transitions of any current screen technology. A 4K OLED gaming screen represents the current benchmark for both gradient smoothness and dark-scene detail — at the cost of burn-in risk for static media production workflows.
- Mini LED: Improves on standard LCD contrast by using thousands of individually dimmed backlight zones, approaching OLED's shadow rendering in practice while maintaining higher peak brightness for high-dynamic-range content.
Completing these diagnostics in sequence — colour banding test, dead pixel checker, backlight bleed test, motion clarity test, and viewing angle evaluation — gives you a thorough, evidence-based assessment of your screen quality, hardware health, and calibration needs. Whether you are setting up a new notebook, validating a gaming screen purchase, or fine-tuning a professional LCD for video editing, each test addresses a distinct dimension of visual fidelity that the others cannot replace.
Frequently Asked Questions
- What is colour banding and why does it happen?
- Colour banding is a visual artefact where a smooth gradient appears as distinct, stepped stripes instead of a continuous transition. It occurs when a display cannot reproduce enough tonal steps — most commonly on 6-bit or 8-bit panels trying to render subtle gradations. It can also be caused by incorrect GPU colour depth settings, lossy cable connections, or OS colour profile mismatches.
- What is the difference between 8-bit and 10-bit in the banding test?
- An 8-bit display can produce 256 shades per channel (about 16.7 million colours total), while a 10-bit display produces 1024 shades per channel (about 1.07 billion colours). The extra steps in a 10-bit display mean gradients appear far smoother. In this test, switching to fewer stress levels quickly reveals whether your panel shows visible contouring at 8-bit vs the smoother output of a true 10-bit display.
- Can banding come from sources other than my monitor panel?
- Yes — banding can originate from several points in the display chain. Your GPU must output full 10-bit colour if your monitor supports it, and you need a high-bandwidth cable (HDMI 2.0/2.1 or DisplayPort 1.4+) to carry it. The operating system's colour depth settings, browser rendering, and even screenshot tools can all introduce or mask banding that the panel itself doesn't cause.
- What does the Shadow Detail test check?
- The Shadow Detail test focuses on the 0–10% brightness range to reveal black crush, where near-black tones are clipped to pure black, and dark-scene detail is lost. This is important for gaming and film viewing where subtle shadow detail matters. Monitors with poor gamma calibration or aggressive dynamic contrast often fail this part of the test.
- What is dithering and is it normal to see it in the dark areas?
- Dithering is a technique used by 6-bit and some 8-bit TFT panels to simulate more tonal steps by rapidly alternating pixels. In dark areas of the gradient, this shows up as a fine static or moving grain pattern. A small amount of dithering is normal for these panels, but heavy noise patterns or moving artefacts suggest the panel's dithering algorithm is poorly implemented or the signal chain is degrading quality.
- How do I fix colour banding on my monitor?
- Start by confirming your cable supports full colour depth — use HDMI 2.0/2.1 or DisplayPort 1.4+. Check your GPU driver and OS display settings to ensure the colour output is set to 10-bit if your monitor supports it, and that the colour range is set to 'Full' (not 'Limited'). Calibrating your monitor's gamma and brightness settings can also reduce banding in the mid-tones. If banding persists after these steps, it is likely a hardware limitation of your panel.
- Why does the gradient look different in my browser compared to a dedicated app?
- Browsers apply colour management using your operating system's ICC/ICM colour profile, which can alter how gradients are rendered and introduce or hide banding. Some browsers also compress or quantise colour values. For the most accurate banding test, ensure hardware acceleration is enabled in your browser, and try the test in a different browser if results seem inconsistent.
- What banding score means my monitor is performing well?
- A score of 80–100 indicates minimal or no banding — your display chain is delivering smooth gradients appropriate for its bit depth. Scores of 50–79 suggest mild banding that may be acceptable for general use but could be improved. Scores below 50 indicate significant banding that will be noticeable in photographs, video, and dark game scenes, and warrants investigation of your cable, GPU settings, and monitor calibration.