Contrast Test
Squint or step back. Checkerboard average should equal solid gray.
You should see a checkerboard with crisp borders. Squint slightly — the averaged checker should match middle gray RGB(128). If uneven, revisit contrast/gamma curves.
How to use
- Squint softly or blur vision until the tiled side homogenizes — it should converge toward mid gray beside the literal patch.
FAQ
Why checkerboard averages to gray?
Equal black white tile coverage perceptually averages to mid luminance assuming linear-ish perception and proper gamma staging.
Overview
This reproduces textbook contrast QA: crisp tile edges plus a calibrated mid-gray comparator on the opposing half-plane.