Gamma Calibration Test
Mathematical visual gamma evaluation patterns. 1-pixel alternating black/white stripes create a physically averaged 50% luminance field. The solid center square is rendered at exact digital values corresponding to target gammas (1.8, 2.0, 2.2, 2.4).
Technical Scope & Limitations
Visual gamma estimation tool. It is NOT equivalent to an instrumented colorimeter hardware LUT measurement.
Hardware Note: For color-critical workflow, use a hardware spectrophotometer (e.g. Calibrite / Datacolor) with internal LUT calibration.
Browser rendering output can be influenced by OS display scaling, GPU driver color settings, and active HDR profiles.
- Sit at your normal viewing distance directly in front of the screen.
- Slightly blur your vision or squint your eyes so the alternating stripes merge into a solid tone.
- Look at the center square: under the correct gamma setting (typically 2.2 for sRGB/Windows/Mac), the center square will blend seamlessly with the striped surround.
- Switch between target gammas 1.8, 2.0, 2.2, and 2.4.
Sit at normal viewing distance (50–70 cm). Squint slightly or defocus your eyes so the black/white striped surround appears as an even gray. The center patch should blend smoothly into the surround when your monitor matches the target gamma.
What This Test Checks
- Display gamma curve alignment against target 2.2 (standard sRGB).
- Shadow lift vs highlight crushing caused by improper gamma presets.
- Viewing angle gamma shift characteristics.
How to Perform the Test
- Sit at normal viewing distance in front of your display.
- Squint slightly so the alternating lines blur together into an even gray.
- Check target 2.2: the center square should blend with the background.
- If the center square is too bright or too dark, adjust your monitor OSD Gamma setting.
What to Look For
- At the correct gamma, the center box melts seamlessly into the surrounding pattern.
- If the box is lighter than the surround, gamma is too low (<2.2, washed out shadows).
- If the box is darker than the surround, gamma is too high (>2.2, crushed blacks).
Common Display Problems & Diagnostic Guidance
Why is Gamma 2.2 standard?
Gamma 2.2 was standardized for sRGB and ITU-R BT.709 because it matches human visual perception and non-linear liquid crystal electro-optical transfer functions.
Frequently Asked Questions
How do mathematical gamma patterns work?
1-pixel alternating black and white lines produce exactly 50% physical area luminance. Under a 2.2 gamma curve, 50% luminance corresponds to digital value (0.5)^(1/2.2)*255 = 186. The center patch renders this exact digital code.