Color Gradient Test Online

Color banding occurs when a smooth color gradient - like a sunset sky fading from orange to blue - appears as discrete visible steps instead of a continuous transition. It is caused by limited color bit depth. This test displays a gradient from black to a pure color (or through the full hue spectrum) and asks you to identify whether the transition is smooth or shows distinct bands. A 10-bit panel can display 1,024 levels per channel (1.07 billion colors), which is essentially invisible banding. An 8-bit panel shows 256 levels per channel (16.7 million colors) - usually smooth enough for most content. A 6-bit panel (64 levels) shows visible banding on gradients.

Monitor bit depth refers to how many distinct brightness levels each color channel (red, green, blue) can display. 6-bit panels display 64 levels per channel (262,144 total colors) - budget panels that use temporal dithering to simulate 8-bit. 8-bit panels display 256 levels per channel (16.7 million colors) - the standard for most consumer monitors. 10-bit panels display 1,024 levels per channel (1.07 billion colors) - professional and HDR monitors. In practice, 6-bit panels with FRC (Frame Rate Control) dithering can produce gradients nearly as smooth as true 8-bit in photographic content, but color banding is visible on test patterns.

Posterization is the visual result of color banding - gradients appear as flat bands of color rather than smooth transitions, similar to a poster or comic art effect. In monitor testing, posterization on a grayscale gradient indicates limited bit depth or poor gamma calibration. It can also be caused by aggressive image processing, incorrect color settings, or a malfunctioning GPU output. If you see distinct bands on the 256-step smooth gradient but not on a photographic image, your monitor may have active image processing that affects gradients.

Many 6-bit monitors use FRC (Frame Rate Control) or temporal dithering to simulate more color levels than the panel hardware can actually produce. FRC rapidly alternates between two nearby colors to create the impression of an intermediate color. On this gradient test, FRC dithering may produce a slightly noisy or textured appearance on gradients rather than clean bands, which can make a 6-bit panel appear better than it actually is. True 8-bit panels produce smooth, noise-free gradients on the 256-step test.

Photographic images contain natural variation, noise, and texture that masks color banding. Smooth synthetic gradients like this test are the most demanding scenario for color depth - they expose limitations that would be invisible in real-world content. Mild banding visible only on gradient tests but not in photos or video is generally not a problem for everyday use. However, if you are editing photos or video and need accurate gradient reproduction (for sky gradients, skin tones, smooth backgrounds), a true 8-bit or 10-bit panel is recommended.

The RGB combined test displays red, green, and blue gradients in three separate horizontal bands. This allows you to compare gradient smoothness across channels. Ideally, all three channels should show identical smoothness. If one channel shows more banding than others, it may indicate an uneven display calibration or a panel defect in that color channel. You can also compare the relative "brightness" of each channel at the same nominal level - if green appears much brighter than red or blue at identical percentages, your white point may need calibration.

The hue sweep test displays the full color wheel from red through yellow, green, cyan, blue, magenta, and back to red. It is useful for evaluating color gamut coverage (whether the monitor can reproduce saturated colors), color accuracy at different hues, and identifying any color channels that saturate or clip before others. A monitor with a wide color gamut (DCI-P3 or Adobe RGB) will show more vivid, saturated colors in the sweep compared to an sRGB-limited panel.