Algorithm guide

Riemersma Dithering Online

Updated June 2026 · 5 min read

Riemersma dithering online uses a Hilbert space-filling curve to carry error diffusion along a continuous path — reducing worm artifacts in smooth gradients. Diffused Editor includes Riemersma free with live preview.

Quick answer: Riemersma dithering online diffuses error along a Hilbert curve instead of row-by-row scanning, producing worm-free smooth gradients. It is a free algorithm in Diffused Editor — ideal for skies, backgrounds, and fine tonal work.

What is Riemersma dithering?

Published by F.W. Riemersma in 1998, this algorithm traverses the image along a Hilbert space-filling curve rather than standard left-to-right rows. Error propagates to previously visited neighbors along the curve path, breaking the directional bias that causes "worm" patterns in large flat areas of conventional error diffusion.

Photo with Riemersma dithering online — Hilbert curve smooth gradients
Still life with Riemersma — smooth worm-free tonal transitions.

Riemersma vs Floyd-Steinberg

Floyd-Steinberg is faster and the standard default. Riemersma excels when smooth areas show visible error-diffusion worms under Floyd-Steinberg — large skies, studio backgrounds, and minimalist compositions benefit from the Hilbert traversal.

How to apply Riemersma dithering online

  1. Open Diffused Editor and upload your image.
  2. Select Riemersma (Hilbert Curve) from the algorithm dropdown.
  3. Use intensity 90–110% and compare with Floyd-Steinberg via the A/B divider.
  4. Download free 50% JPEG or Pro full-resolution export.

Frequently asked questions

What is Riemersma dithering?

Riemersma is an error diffusion algorithm that follows a Hilbert space-filling curve, distributing quantization error along the curve path to reduce worm artifacts in smooth gradients.

Is Riemersma dithering free online?

Yes. Riemersma is included in Diffused Editor's free tier alongside nine other algorithms.

When should I use Riemersma over Floyd-Steinberg?

Use Riemersma when large smooth areas show directional worm patterns under Floyd-Steinberg. For general photos, Floyd-Steinberg or Stucki may be simpler defaults.

Try Riemersma dithering — Hilbert curve, free in browser.

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