The Ditherer.

or, make your own guardian.

The guardians for this site went through this pipeline: image → grayscale → a sigmoid contrast curve (it crushes the darks to solid ink and blows the lights out to paper, enhancing readability) → Atkinson error diffusion, the same algorithm developed at Apple for the OG Macintosh → glyphs.

Drop an image below and drag the sliders. Everything runs right here in your browser; nothing gets uploaded anywhere. If you'd rather have the code, the whole thing lives in the design lab on GitHub, MIT licensed.

atkinson error diffusion · deterministic · runs locally

A tip from my own tuning: statues want high contrast (8–10) and a midpoint a smidge below center, so the figure goes solid and the background falls away. Faces want gentler settings.