1-Bit Dither: Two Colors, Infinite Mood

Get the early-Mac, fax-machine, risograph look with Yan's 1-bit dither. Threshold, Floyd-Steinberg, Atkinson, and Bayer — explained.

> The Short Answer

1-bit dither expresses a full-colour image using only black and white, creating the illusion of grey through dot density. You can test both ordered and error-diffused dithering online for free with our Dither Converter tool. Four algorithms give four distinct looks: Threshold is hard and posterised with no mixing, Floyd-Steinberg diffuses rounding error into neighbouring pixels for smooth photographic gradients, Atkinson diffuses only part of the error so highlights blow out brighter (the classic Macintosh look), and Bayer uses an ordered matrix that leaves a visible regular halftone pattern. In the Yan mobile app, Threshold 128 is neutral and Pixel Scale creates chunkier lo-fi dots.

What 1-Bit Dither Does

You have an image with 16 million colors. You're going to express it using two: black and white. Dithering decides where each one goes.

You can try these algorithms immediately in your browser with our free Dither Converter.

1-Bit Dither Algorithm Diagram

The illusion of gray comes from dot density. Lots of black pixels close together = looks dark. Sparse black on white = looks light. Stand back from the screen — your eye averages it.

Four Algorithms

Each produces a distinct look. Try all of them on the same image.

Threshold
Pixels above the threshold become white, below become black. No mixing. Hard, posterized. Best for high-contrast graphics and logos.

Floyd–Steinberg
Error diffusion: when a pixel rounds to black or white, the leftover "error" is pushed to neighboring pixels. Result: soft, slightly fuzzy gradients. The most photographic of the four.

Atkinson
Like Floyd–Steinberg but only diffuses 75% of the error and skips some neighbors. The result is brighter and more contrasty — this is the dither used on the original Macintosh.

Bayer
Uses an ordered matrix (2×2, 4×4, or 8×8) to decide threshold per pixel. The output has a visible regular pattern — looks like a pre-print halftone. Best when you want the pattern visible.

Try It in the Browser

You can experiment with both ordered dithering and error diffusion right now without installing anything via our free Dither Converter.

While the Yan mobile app provides raw numeric controls (Threshold, Bayer Size, Pixel Scale) with multi-layer real-time GPU pipelines, the browser tool delivers a clean Canvas 2D engine with direct algorithm-to-filter mapping:

AlgorithmBrowser FilterDiffusion KernelOutput Style
Bayer OrderedBitgrain8×8 Bayer matrixRegular crosshatch texture, 3–5 levels
Floyd–SteinbergCobalt GrainStandard 4-tapTrue 1-bit, balanced tonal gradation
AtkinsonDenim Grain6-tap (discards 25% error)True 1-bit, high contrast, classic Mac
Custom 3-TapHarbor Grain3-tap forwardTrue 1-bit, directional graphic grain
Custom 7-TapMeadow GrainTwo-row 7-tapTrue 1-bit, soft organic dispersion

In the browser tool, Detail adjusts threshold and quantisation density, Contrast shapes the luminance curve before dithering, and Intensity blends against the original photo.

App Parameters

When using the Yan mobile app, you have access to low-level controls:

Threshold (0–255)
Center point for black vs white. 128 = neutral.

  • Lower: more white pixels, brighter overall
  • Higher: more black pixels, darker overall

Bayer Size (2 / 4 / 8) — Bayer only
Smaller = chunkier visible pattern. Larger = finer, almost smooth.

Pixel Scale (1–8)
Downsamples before dithering. Higher = bigger, retro lo-fi dots.

Good Subjects

  • Portraits: Atkinson gives that classic MacPaint face look
  • Landscapes: Floyd–Steinberg keeps tonal range
  • Type and logos: Threshold, crisp
  • Anything you want to feel printed: Bayer with low size

Recipes

You can dial these in with the mobile app or test similar looks online via Dither Converter:

Original Macintosh

  • Atkinson, threshold 128, pixel scale 2
  • Looks like 1984 MacPaint

Newspaper Halftone

  • Bayer, size 4 or 8, threshold 128
  • Print-shop dots

Risograph

  • Floyd–Steinberg, threshold ~140
  • The slightly imperfect zine vibe

Fax Machine

  • Threshold, pixel scale 4
  • Pure crunch

What to Avoid

  • Subtle gradients you need to keep smooth: pick Floyd–Steinberg, not Threshold
  • Very small text: dither and font can fight

Combinations

  • Dither + CRT: scanlines on a 1-bit image. Computer terminal from another era.
  • Dither + RGB Shift: wait — RGB Shift adds color back. Run dither last for pure 1-bit. Or run RGB first for split-channel dithered chaos.
  • Dither + Block Jitter: scanned-and-corrupted printout.

The Idea

Two colors is more than enough. The rest is math.

> Frequently Asked

Can I dither an image online for free?
Yes. The free Dither Converter tool runs entirely in your browser using Canvas 2D. It requires no installation, no account, and never uploads your images to any server, exporting full-resolution PNGs with zero watermark.
What is the difference between ordered dithering and error diffusion?
Ordered dithering compares each pixel to a fixed threshold matrix (like an 8×8 Bayer grid), producing a fast, deterministic, crosshatch pattern. Error diffusion calculates the rounding error for each pixel and distributes it to neighbouring pixels, creating an organic, fine-grained, photographic appearance.
Which dithering algorithm should I choose?
Floyd-Steinberg for photographs, because error diffusion preserves tonal range. Atkinson for a brighter, higher-contrast result with cleaner whites. Threshold for logos and high-contrast graphics where you want hard edges. Bayer when you actually want the regular pattern to be visible.
What does the threshold setting do?
It sets the centre point between black and white, with 128 as neutral. Lowering it turns more pixels white and brightens the whole image; raising it turns more pixels black and darkens it.
How do I get the original Macintosh look?
Atkinson at threshold 128 with pixel scale 2. Atkinson discards part of the accumulated error rather than distributing all of it, which is exactly why 1984 MacPaint images have that bright, crunchy contrast.