Gamma Test

Gamma decides how bright the midtones look between black and white. These patterns let you estimate your gamma and check that dark and bright detail is not lost.

Step back or squint until the stripes blur, then find the patch whose center blends into its surround. That patch's number is your approximate gamma.

Set browser zoom to 100%: the stripe patches need whole pixels.

Runs entirely in your browser. Nothing is uploaded or stored.

How to use

  1. Use your normal brightness setting, sit at your usual distance, and set browser zoom to 100%.
  2. Press Start test and move through the four patterns with the arrow keys, a tap, or the Previous and Next buttons.
  3. On Gamma chart, step back or squint until the striped patches blur into flat gray, then find the patch whose center blends into its surround. Its label is your approximate gamma.
  4. On Shadow detail, find the first bar you can separate from black.
  5. On Midtones, check that the steps look evenly spaced.
  6. On Highlight detail, find the first bar you can separate from white.

What this test can detect

  • A gamma that is too high (crushed, dark midtones) or too low (washed-out midtones).
  • Lost shadow detail: the first few dark steps look the same as black.
  • Clipped highlights: the last few bright steps look the same as white.
  • Uneven midtone steps that suggest a poor gamma curve or tone mapping.

Important

  • The chart estimates gamma to about 0.2. It is a visual check, not a measurement.
  • The stripe patches rely on 1-pixel lines. Browser zoom or display scaling that is not a whole number can blur them and skew the result.
  • Room light and reflections lift the apparent black level and change what you see in the dark steps.