Black and white clipping test: can you see the dimmest shades?

How this is calculated

The near-black pattern draws patches at code values 1 to 16 on a background of 0. The near-white pattern draws 239 to 254 on 255. On a well set up PC monitor, you'll usually see most of the dark patches in a dim room, with the faintest ones hard to separate from black, and most of the bright patches, with the ones closest to white very subtle. Two common settings break this. The first is RGB range. PC monitors expect full range, where black is 0 and white is 255. TVs and some consoles use limited range, where black is 16 and white is 235. If your graphics card sends full range to a screen that expects limited range, every value up to 16 turns black and every value above 235 turns white, so the dark and bright patches all disappear. The opposite mismatch makes black look gray and washed out. The second is brightness and contrast. A brightness setting that's too low crushes the shadows, and contrast or a picture mode pushed too high clips the highlights. Gamma settings and dynamic contrast change the dim patches too. Test at your normal settings and room light, since a bright room hides the faintest shades on any screen.

Verdict

If the whole near-black row is missing or black looks gray, check the RGB range in your graphics driver and the monitor's input settings first. Then adjust brightness until the dim patches just show, and contrast until the bright ones just show. This uses code values, not measured light, so it can't confirm a calibration or an HDR mode. For that you need a colorimeter.