Black Level Test

How this test works

Adjust your setup until the darkest intended patches are barely distinguishable from the background.

1. Prepare the display using the checklist below.
2. Select Start test and allow fullscreen mode if your browser asks.
3. Use the arrow keys, on-screen controls, or click the pattern to move through the test.
4. Exit the runner and save a local observation if useful.

Before you begin

• Use subdued room lighting
• Disable dynamic contrast
• Allow your eyes to adapt briefly

What to look for

• Which numbered dark patches are visible
• Tint in near-black gray
• Black crush or an overly raised black floor

Read the near-black steps carefully

The pattern places several numbered near-black gray patches against a black background. Give your eyes a short moment to adapt in subdued room light, then note which patches you can separate from the background. The darkest steps are intentionally difficult. The question is not whether every square is obvious; it is whether several neighboring dark shades unexpectedly collapse into the same black or whether the background looks raised and gray. Compare one picture setting at a time while keeping your viewing position and room conditions stable.

Shadow detail depends on the whole signal path, including content range, graphics settings, picture mode, ambient light, and panel technology. If a mode reveals more numbered patches but makes black look washed out, it may be lifting the dark range rather than restoring a faithful image. Conversely, a punchy mode can hide intended detail. The browser pattern helps you compare visible separation; it does not measure black luminance, native contrast ratio, or the correct transfer function of your setup.

Control room light and display settings

Reflections can cover the darkest patches even when the display is producing them. Dim the room moderately, avoid direct glare, and use a normal brightness setting. Disable dynamic contrast for one comparison, since it can change the panel output depending on the scene. Allow your eyes to adapt briefly rather than staring at a bright page and switching immediately to black. If you use an OLED screen, do not leave a static pattern up for a long time while making adjustments.

If the result changes when you switch an HDMI range, graphics output mode, or local-dimming setting, note both settings rather than assuming the panel is defective. Incorrect limited-versus-full range handling can alter tonal relationships, but this page cannot diagnose which device applied which mapping. Viewing angle matters too: on some LCDs, dark patches near an edge look different from the center. Inspect from your normal seated position before drawing conclusions from an extreme angle or a close-up phone photo.

Use the result as a comparison, not a specification

Repeat the same pattern after each change and write down which numbered patches became visible or disappeared. Then look at dark scenes in familiar content to decide whether the setting improves practical shadow detail without making black unnaturally pale. If you are seeing a broad glow or patch only near the edges of an LCD, use the backlight bleed or uniformity tests; if the issue is an isolated pixel, use solid colors instead. This page is narrowly about tonal separation near black.

A browser cannot calculate contrast ratio by showing black and gray. That requires controlled luminance readings, and camera exposure can make a dark panel look much brighter than it appears to your eyes. For HDR-specific questions, the HDR page reports browser capabilities but likewise does not measure brightness or tone mapping. Keep the observation in plain terms—such as which patches you can distinguish under what conditions—so you can compare picture modes or describe a concern without claiming an instrument-grade result.

Frequently asked questions