Nested barsSymmetrical PLUGE-style layout

Compare matching bars on both sides of the zero reference to spot crush or uneven dark rendering.

Rendering OrientationShow value labelsDark-step range0–5%Full-field level1.0%

←→ patternsF fullscreenC controlsEsc exit

Select the field to activate keyboard and swipe controls.

Find the first visible steps above black

Black Level Test

The black level test concentrates requested RGB values within the first few percent above black. Use the default 0–5% range, symmetrical PLUGE-style bars, a step ladder, distributed patches, or an individual full-field level to inspect black crush, raised blacks, and near-black uniformity by eye.

Dark adaptation without guesswork

Run the black level test in five passes

Reduce glare, not all context. Use a dim environment representative of dark viewing. Shield obvious reflections and allow your eyes a short adaptation period before deciding which patch is visible.
Keep the range at 0–5% first. In the nested-bars pattern, the center is the zero reference. Compare matching bars outward and note the first pair you can distinguish from the background.
Check the step ladder. An ordered sequence makes black crush easier to describe. Increase the dark-step range only if the default pattern remains mostly merged; doing so changes the question rather than improving the display.
Move the same tones around the screen. Zone patches can expose a near-black difference across panel areas. Change your viewing angle separately because IPS glow and some OLED tint behavior can shift with position.
Isolate one full field. Select full-field rendering and move through levels in 0.5% increments. Use this black level test mode for broad banding or tint, then return to normal dark content for context.

Three appearances with different meanings

Black crush, raised black, and uneven black

Black crush

Black crush describes low shadow values merging into black, removing visible detail. Picture settings, signal range, tone mapping, room light, and panel behavior may contribute. The black level test shows the merge but does not locate its cause.

Raised blacks

A black reference that appears grey can come from room reflections, an elevated black setting, limited-range mismatch, LCD backlight leakage, or other processing. Physical luminance measurement is needed to quantify it.

Near-black non-uniformity

Vertical bands, tint, or patches at low levels can change with warm-up, compensation behavior, viewing angle, and the requested code. Compare more than one level before describing the pattern.

Display technology changes the context

OLED and LCD black are not the same mechanism

An LCD modulates a backlight, so a requested black pixel can still be viewed against transmitted or leaked light. Panel type, viewing angle, local dimming, and backlight construction influence the visible field. Edge glow on a dark LCD should also be cross-checked with the backlight bleed workflow.

OLED pixels are emissive and may turn off for zero, yet near-black drive, compensation, temporal dithering, tone mapping, and panel uniformity still affect levels just above black. The black level test can reveal those visible differences without measuring their luminance or declaring them outside a manufacturer specification.

Original source patterns

How the near-black fields are rendered

Patch family

The renderer divides the selected percentage range into six integer RGB codes. The step ladder orders them across one axis. The symmetrical pattern places a zero bar between mirrored levels, and zone mode distributes the same family across the field.

Full-field family

Full-field mode converts the chosen percentage to one neutral RGB code and fills the canvas. Rounding to 8-bit canvas values means very small percentage changes can map to the same integer. Labels describe requested source values, not measured light output.