There is no universal normal level
Check that several near-black steps separate gradually at the target brightness and room light, then compare with records from the same display and settings. Panel behavior and transfer functions differ.
Black Level Test
Step through near-black patches from 1 to 32 and record the gray level that first separates from a pure-black background on your display.
Test conditions and observation controls
Start low and increase the level until the patch can be separated reliably from the pure-black background.
This records the current display setting only; it does not control system or hardware brightness.
Local-dimming displays can produce different observations at different patch sizes.
In full screen, use the arrow keys to change the level. Press Enter to record and exit; press Esc to exit without recording.
Start at a low level; no result has been recorded.
Lowest visible level
—
Adjust the patch and record the level when it first becomes consistently visible.
- Code value
- —
- Brightness record
- 30%
- Room conditions
- Dark room
- Local dimming
- Unknown or not applicable
- Patch size
- Medium patch (about 32%)
This is a visual record under the current conditions, not an instrument reading of black level, contrast, or a universal pass decision.
How to read a near-black observation
After recording, the first visible position will be marked on the 1–32 range. It represents an RGB code value, not a physical luminance ratio.
Black crush, bleed, and IPS glow are different observations
Black crush makes the whole image lose shadow detail; backlight bleed is usually a fixed bright edge or area; IPS glow changes with angle and distance. A near-black record cannot separate them automatically.
Local dimming changes the observation
Local dimming changes backlight zones based on patch size and position and can darken the background or create a halo. Keep the mode, patch size, brightness, and room light fixed for comparisons.
Learn more
Method and repeat check
The canvas uses RGB(0,0,0) for the background and RGB(n,n,n) for the centered patch, where n is the selected integer from 1 to 32. The tool does not measure the display output or grade it against an arbitrary threshold.
For a repeat check, keep viewing position, brightness, room light, local dimming, and patch size fixed and repeat the sequence from low to high twice. Large differences may indicate dark adaptation, reflections, or dynamic display settings.
Scope and common interference
Browser color management, system HDR, display dynamic contrast, local dimming, OLED black behavior, viewing angle, reflections, and visual adaptation affect the result. A camera photo cannot replace visual observation or a luminance meter.
Tool information
This tool runs entirely in the current browser. It does not upload test conditions or observations, call a remote API, or write to local storage or a shared URL.
This tool uses standalone HTML, CSS, and JavaScript and includes no third-party runtime library.
Frequently asked questions
What gray level should appear first in a normal black level test?
There is no fixed normal level for every display and environment. Compare the same display and settings under the target brightness and room light instead of applying one universal number.
How do black crush, backlight bleed, and IPS glow differ?
Black crush hides shadow detail across the image, backlight bleed usually appears as a fixed bright edge or area, and IPS glow changes noticeably with angle and distance. This near-black record cannot identify them automatically.
Why does local dimming change the result?
Local dimming changes backlight zones according to patch size and position. Fix the dimming mode, patch size, brightness, and room light when comparing records.