White Level Test
Set and check your monitor's white level — the brightness and neutrality of pure white. A full-screen pure-white field exposes tint and uniformity, near-white step patches show whether the brightest tones still separate, and a light-grey-to-white gradient reveals where highlight detail is lost. White level is set mainly by the Contrast control; this is a visual guide, not a measurement.
← → change pattern
The Contrast control scales the brightest tones. Too high clips highlight detail; too low leaves whites dull and grey. Set black level with Brightness first.
On the near-white pattern, tune Contrast until levels 254 and 253 are only just visible against pure white without merging into it.
If white looks yellow or blue, set the colour-temperature preset to 6500K and fine-tune with the RGB gain (white balance) sliders. This is a visual guide, not a measurement.
What white level means
White level is how bright and how neutral your display drives pure white — the signal at level 255. It is governed mainly by the monitor's Contrast control, which scales the top of the tone range, while the Brightness control sets the black level at the bottom. A correctly set white level makes white look clean and bright without crushing the faint tones just below it, and a correct white point (colour temperature) makes it look neutral rather than tinted warm or cool. Peak white is one anchor of your panel's dynamic range; black level is the other, which is why white level pairs naturally with a black-level or contrast check.
The three test patterns
- Pure white field: a full screen of level-255 white. Judge peak brightness, look for a colour cast (a yellow or blue tint), and scan for the "dirty-screen effect" — faint smudges, blotches or edge-to-centre unevenness that reveal poor uniformity.
- Near-white steps: patches at levels 254, 253, 252, 250, 248, 245, 242, 238 and 232 sit on a pure-white (255) field. Every patch should stay just distinguishable from its neighbours and from the field; if the brightest few merge into one white, your highlights are clipping.
- Grey-to-white gradient: a smooth fade from light grey up to pure white, with a stepped bar beneath it. The fade should climb evenly and the steps should stay separate right up to 255 — the point where they stop changing is where highlight detail is being lost.
White clipping and blown highlights
When Contrast is set too high, the brightest input levels all map to maximum output and become indistinguishable — this is white clipping, and the detail it destroys is called blown highlights. On the near-white pattern it shows up as the top steps (254, 253, 252) merging into the surrounding white; on the gradient it shows as the fade flattening to a solid white band before it reaches the right edge. Lower Contrast until those top steps reappear as distinct tones. Clipping is not always the monitor's fault: an incorrect signal range (limited vs. full RGB) between the GPU and display, or an aggressive dynamic-contrast mode, can clip whites even when Contrast is reasonable.
How to set your white level
- Turn off any dynamic-contrast or "eco" mode first — it moves the white level around while you are trying to set it.
- Set the black level with the Brightness control before touching white, then adjust the Contrast control while watching the near-white steps: raise it until whites look bright, then back off until levels 254 and 253 are just visible against pure white.
- Set the white point with the colour-temperature preset. Aim for 6500K (often labelled "Warm", "6500K" or "sRGB") so white looks neutral rather than blue or yellow.
- For fine control, use the OSD's RGB gain (white balance) sliders to remove any remaining tint from the pure-white field.
- White level works together with black level and gamma — cross-check with the Contrast Test for the full black-to-white range and the Gamma Test for mid-tone accuracy.