Why do we need dithering?

Original Article ↗ Hacker News Discussion ↗

Is Dithering Still Needed?

  • Strong disagreement with the article’s claim that we “don’t really need dithering anymore.”
  • Many point out obvious banding in modern games and gradients (e.g., blue skies, dark scenes) when dithering is absent or poorly done.
  • 8 bits per channel (24-bit color) is often insufficient for smooth gradients, especially large or nearly monochrome ones; dithering hides banding without increasing bit depth.
  • Dithering is widely used in modern rendering pipelines: render to high-precision buffers, then dither when quantizing down.
  • Display hardware frequently uses spatial/temporal dithering (“frame rate control”) to simulate extra bits of color.

Tradeoffs, Techniques, and Use Cases

  • Static dither patterns can be used in video to avoid flicker and keep content compressible.
  • Screen-space dithering is used for cheap transparency and to improve dark scenes in games; some dislike the resulting “sparkly” artifacts, especially when combined with TAA.
  • For streaming, adding real noise is problematic because codecs remove it; better if noise/dither is added on the client side (e.g., synthetic film grain).

Beyond Images: General Signal Processing

  • Dithering is emphasized as a fundamental quantization tool, not just a graphics trick.
  • In audio, dithering and noise shaping are standard for high-quality 16‑bit output.
  • Conceptually, “add jitter as close to the quantization step as possible” applies to any thresholding or bit-depth reduction, including Monte Carlo sampling, geometry, etc.

Aesthetic and Nostalgia

  • Some use dithering intentionally as a “retro” or low‑fi aesthetic, referencing classic games and 1‑bit/limited‑palette hardware.
  • Return of the Obra Dinn and PlayDate titles are cited as exemplary stylistic uses.
  • A subset of commenters say that, given modern full-color displays, their motivation to dither is mainly aesthetic or for file-size games (e.g., PNG‑8).

Color Spaces, Perception, and Theory

  • Discussion touches on sRGB’s nonlinearity, gamma (≈2.2), and why proper dithering and calculations should be done in linear light with higher internal precision.
  • For multi-color dithering and palette selection, commenters suggest working in perceptual spaces (e.g., Lab) to measure color similarity.
  • With sufficiently high spatial resolution, dithering trades spatial resolution for perceived color resolution, making lower bit depth more usable.