Contrast test
A monitor that looks punchy is often just throwing away detail. Two ladders of nearly identical patches will tell you how much of the shadow and highlight range your screen can actually show, and how much it is quietly discarding.
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Could you tell every patch apart on both ladders?
How to read the two ladders
The test shows two ladders. Press space to switch between them.
The black ladder is a row of very dark grey patches on a black background, labelled with their brightness value from 1 to 20. Count how many you can distinguish from the background and from each other.
The white ladder is the mirror image: near-white patches on white, from 254 down to 235.
Give each one about ten seconds. Near-black separation in particular takes a moment for your eyes to resolve, and the first glance always undercounts.
What the count tells you
| Result | What it means | What to do |
|---|---|---|
| All patches visible on both | Correctly adjusted | Nothing |
| Bottom 2–4 black patches invisible | Mild black crush | Raise brightness or black level slightly |
| Bottom 5+ black patches invisible | Heavy black crush | Turn off dynamic contrast, check gamma |
| Top 2–4 white patches invisible | Mild highlight clipping | Lower contrast a few steps |
| Top 5+ white patches invisible | Heavy clipping | Check for a limited-range signal, see below |
| Both ends collapsed | A picture mode is doing this | Switch the monitor to Standard or sRGB mode |
The single most common cause: limited range
If both ends collapse at once and no monitor adjustment fixes it, the graphics driver is almost certainly sending a limited-range signal (16–235) that the monitor is displaying as full-range (0–255), or the reverse. It happens most often over HDMI, because HDMI defaults to limited range for televisions.
Windows 11, NVIDIA: NVIDIA Control Panel → Display → Change resolution → Output dynamic range → set to Full.
Windows 11, AMD: AMD Software → Settings → Display → Pixel Format → set to RGB 4:4:4 Full RGB.
Windows 11, Intel: Intel Graphics Command Center → Display → General → Quantization Range → Full Range.
If the monitor has its own HDMI black level setting, it must agree with the driver — set one to full and the other to limited and you get exactly this fault.
macOS
macOS handles range automatically over DisplayPort and Thunderbolt, and usually gets HDMI right too. When it does not, the symptom is washed-out blacks on an external monitor:
- Check the monitor own HDMI black level setting first and set it to Normal or Full.
- Colour profile matters more on macOS than range does. System Settings → Displays → Colour profile: pick the profile that matches the display, not a generic one.
- Turn off True Tone before judging either ladder.
Before you adjust anything
Set the monitor back to its default picture mode first. Dynamic contrast, game modes, black equalizer, shadow boost and similar features all alter the mapping between signal and light, and any one of them will make this test meaningless. Get a clean result in Standard or sRGB mode, then re-enable whatever you like the look of.
Common questions
What is black crush?
Everything below a certain brightness rendering as the same flat black. Detail that exists in the source — the folds of a dark jacket, objects in a shadowed corner of a game — is simply not shown. It is caused by monitor brightness or black level set too low, an aggressive contrast or dynamic contrast mode, or a gamma setting that does not match the content.
What is white clipping?
The same fault at the other end: everything above a certain brightness renders as identical pure white. Clouds lose their shape, highlights on metal turn into flat patches. It usually comes from the contrast control being pushed too far, or from a limited-range signal being displayed as full-range.
How many patches should I be able to see?
On a well-adjusted monitor, all of them on both ladders, though the darkest one or two take some looking for in a bright room. If you are missing three or more at either end, something is wrong with the settings rather than your eyes.
Does this test measure my contrast ratio?
No, and no browser test can. Contrast ratio is a measurement of luminance, and that needs a colorimeter held against the screen. What this test measures is how much of the range survives to your eye, which is the thing that actually affects what you see — and it is often the more useful of the two.
Why do the dark patches look different on my phone?
Phones apply automatic brightness and, on OLED, their own tone mapping. An OLED phone will usually show more of the dark ladder than an LCD monitor, because its black is genuinely black. Turn auto-brightness off before comparing two devices.