Inspect black clipping, shadow detail retention, and highlight separation across calibrated luminance patterns.
Look closely at the dark patches. You should be able to distinguish step 2% and 3% from pure black 0%.
💡 Lower or raise your monitor brightness until the darkest steps are distinguishable without making black look gray.
A standard web browser cannot measure true physical screen brightness (cd/m² or nits) because web APIs do not have access to photometer sensor hardware. This test provides controlled visual targets so you can adjust your monitor's physical brightness and contrast controls to achieve optimal shadow and highlight distinction.
Evaluates shadow detail visibility and highlight retention across dark, midtone, and bright test fields.
Open your monitor's On-Screen Display (OSD). In Stage 1, adjust brightness until step 2% is barely visible. In Stage 4, ensure step 98% doesn't wash out into 100% white.
Crushed darks: Dark steps merge into 0% black. Blown-out highlights: Bright steps merge into 100% white. Excessive glow: Pure black looks visibly glowing gray.
Screen Tester cannot measure physical luminance (nits / cd/m²) using the browser alone. This test provides controlled visual patterns to evaluate display brightness and shadow visibility.
Tune your monitor's black levels to ensure dark details aren't crushed.
Tune your monitor's contrast to ensure bright details aren't clipped.
Evaluate contrast ratio, color separation, and gradient steps across 25 dynamic levels.
Visually estimate your monitor's gamma tracking (target 2.2 for sRGB).
