Brightness & Contrast Guide
Lower your brightness until the leftmost 2-3 patches merge into one black, then raise it one notch until they just separate again. Every patch from 0 to 26 should be barely distinguishable from its neighbour.
All twelve patches from 244 to 255 should stay distinct. If the rightmost few blow out into a single sheet of white, your contrast is set too high.
Twenty-one even steps from 0% to 100%. The staircase should look evenly spaced end to end, with no sudden jumps and no colour tint creeping into the greys.
Step back to arm’s length and squint. The striped block averages out to 50% luminance, so it should melt into the flat grey patches beside it. If the stripes look darker, your gamma is too high; lighter means too low.
View this card at 100% browser zoom: display scaling or zoom breaks the 1-pixel stripes and can create false shimmer (moiré).
Work through the cards in order, in your normal room lighting. Everything here is plain colour rendered by your own screen; nothing is measured or sent anywhere.
How it works
仕組みA screen that is too bright crushes shadows and burns out highlights; one set too dark hides detail you paid for. This guide walks you through four classic test cards (near-black steps, near-white steps, a full grayscale ramp, and a stripe-based gamma check) with plain instructions for adjusting brightness and contrast by eye. It is inherently a your-own-screen exercise: the patches are rendered live by your panel, in your room, under your lighting, so no article or screenshot can substitute for looking at them yourself. Five minutes here noticeably improves photos, films, and dark-mode interfaces.
There is no universal number, because it depends on your panel and your room lighting. Use the shadow-step card as the anchor: brightness is right when the darkest two or three patches only just separate. In a bright office that usually lands much higher than in a dim evening room, so recheck when your lighting changes.
Almost certainly not. The gamma card relies on true 1-pixel stripes, so any browser zoom or fractional OS scaling (125%, 150%) resamples them and creates moiré patterns. Set the browser to exactly 100% zoom, and on a scaled display take the gamma result with a grain of salt.
For colour-critical work like print, photo editing, or grading, yes: a hardware probe measures things eyes cannot. But for everyday use, by-eye calibration against step wedges catches the big problems: crushed blacks, clipped whites, and badly skewed gamma. Most screens out of the box benefit from exactly these fixes.