Dithering

Dithering fakes a full range of tones with only two colors, or a small palette, by arranging dots cleverly. This page explains all 14 dithering algorithms in Bitgrain, the dither factor, palettes, why resolution changes everything, and a set of recipes to start from.

How dithering works in Bitgrain

Imagine you can only print black or white. Rounding every pixel to the nearest of the two gives you harsh, flat blobs. Dithering rounds the same way, but hides the rounding mistakes in a pattern of dots, so from a normal viewing distance your eye blends them back into greys.

Bitgrain's dither effect works on the working grid:

1. Your adjustments are applied first.
2. Each cell is measured by its luminance (how bright it looks), or by its full color if you picked a palette.
3. The algorithm decides, cell by cell, which tone or palette color it becomes.
4. The result is drawn as a grid of hard-edged 2 x 2 px dots.

Without a palette, a cell is compared against the midpoint and becomes ink or paper. With a palette, it becomes the nearest palette color. What changes between algorithms is how they decide, and that decision is the whole character of the look.

Where to find it

The image editor lists methods in lowercase with dashes removed (for example "floyd steinberg", "sierra 2", "bayer 4"). The video editor and Studio use names like "Floyd-Steinberg", "Bayer 4x4" and "JJN". The headings below use the video and Studio names. The image editor starts on Atkinson, while the video editor and Studio start on Floyd-Steinberg.

The dither effect also has a color switch:

Dither factor

The factor (called Intensity in video and Studio) scales how much of each cell's rounding error is passed on to its neighbours.

• At 1 (100%), the full error is spread, which is the textbook behaviour of each algorithm.
• Below 1, less error travels. Tones drift toward flat black and white areas with dots only near the transitions, which reads as more graphic and posterized.
• Above 1, the error is exaggerated. Texture gets busier, streaks appear, and midtones break up into worm-like patterns. Push it for glitchy looks.

Note: The factor only affects the eight error diffusion methods. Bayer, blue noise, threshold and random ignore it, because they never spread error in the first place.

Error diffusion

Error diffusion methods walk the grid one cell at a time. For each cell they pick the nearest tone, measure the difference (the error), and push fractions of that error onto cells they have not visited yet. Neighbours that received extra darkness are more likely to become ink, so tone is preserved on average.

Bitgrain scans in a serpentine path: left to right on even rows, right to left on odd rows. This avoids the diagonal "rain" that a one-way scan leaves in flat areas.

The algorithms differ in how far the error travels and how it is weighted. Wider kernels (the pattern of neighbours that share the error) give smoother gradients and less visible structure. Smaller ones give crisper, grainier dots.

Floyd-Steinberg

The classic from 1976. The error goes to four neighbours: 7/16 to the right, and 3/16, 5/16 and 1/16 to the three cells below.

• Look: organic, grainy, no repeating grid. Good tone reproduction.
• Use it for: portraits, soft gradients, anything photographic. It is the safest default.

Atkinson

Developed for the original Apple Macintosh. Six neighbours each receive 1/8 of the error, which adds up to only 6/8. A quarter of the error is thrown away on purpose.

• Look: high contrast, clean whites, deep blacks, with delicate dotting in the midtones. Highlights and shadows tend to clip to solid paper and solid ink.
• Use it for: the classic early Mac look, bold graphic prints, images with strong subjects on plain backgrounds. The image editor starts here because it reads beautifully at a glance.

Sierra

The full three-row Sierra kernel, spreading error across ten neighbours (weights in 32nds).

• Look: smooth and even, close to Jarvis-Judice-Ninke but a little faster and slightly crisper.
• Use it for: landscapes and skies where you want smooth gradients without Floyd-Steinberg's grit.

Sierra 2

The two-row Sierra variant, seven neighbours (weights in 16ths).

• Look: a middle ground between Floyd-Steinberg and full Sierra. Smooth, but with a bit more bite.
• Use it for: general photography when Floyd-Steinberg feels too noisy.

Sierra Lite

The smallest kernel in the set: half the error goes right, a quarter to each of two cells below.

• Look: crisp and slightly streaky, with tight dot clusters. Very close to Floyd-Steinberg but more mechanical.
• Use it for: small images, icons and pixel art, where a wide kernel would smear detail.

Stucki

Twelve neighbours across three rows (weights in 42nds), with more weight near the center than JJN.

• Look: very clean and sharp, with smooth gradients and crisp edges. One of the most "printed" looking.
• Use it for: detailed images, architecture, text in photos, and anything you plan to print large.

Burkes

A simplified Stucki that uses only two rows, seven neighbours (weights in 32nds).

• Look: smooth like Stucki but slightly more textured, with good edge detail.
• Use it for: when you like Stucki but want a little more grain.

JJN

Jarvis, Judice and Ninke's kernel: twelve neighbours across three rows (weights in 48ths), the widest spread of the group.

• Look: the smoothest gradients of all, with fine, even dots and very little visible pattern.
• Use it for: gentle tonal work, skin, fog and gradients where you want the dithering to almost disappear.

Ordered and threshold methods

These methods decide each cell on its own, by comparing it to a threshold. No error is passed around, so there are no streaks and no worms, and one cell never affects another. That makes them stable: move part of the image and the rest does not change. It is also why they hold up well in animation.

In the image editor, these six sit under the "Ordered" heading.

Bayer 2x2

A tiny repeating 2 x 2 threshold pattern, so only five distinct tone levels are possible.

• Look: a coarse, very visible checkerboard grid. Extremely retro.
• Use it for: deliberately crude 1-bit graphics and tiny icons.

Bayer 4x4

A 4 x 4 pattern giving 17 tone levels.

• Look: the familiar crosshatched grid of early computer and handheld console graphics.
• Use it for: retro game and pixel-art looks, especially with a small console palette.

Bayer 8x8

An 8 x 8 pattern giving 65 tone levels.

• Look: a finer, smoother version of the same grid. Gradients look like fabric or a woven screen.
• Use it for: smooth ordered gradients, UI-style art, and anything you want to animate without flicker.

Blue noise

A 16 x 16 threshold tile arranged so dots spread evenly with no obvious grid and no clumps.

• Look: like error diffusion's organic grain, but with the stability of an ordered method. Very even and calm.
• Use it for: photos you want to look natural but still behave predictably, and for video.

Threshold

No dithering at all. Every cell is simply ink or paper depending on whether it is darker or lighter than the midpoint. With a palette, each cell just becomes its nearest palette color.

• Look: stark, flat, stencil or photocopy-like.
• Use it for: graphic silhouettes, posters, and stencils. Raise Contrast first so the cut lands where you want it.

Random

Each cell is compared against a noise threshold, so tone becomes pure static.

• Look: gritty static, like old film or a noisy scanner.
• Use it for: lo-fi texture and grunge. The noise is seeded, so the same settings always place the same dots.

Choosing an algorithm

Color, colorize and palettes

Dithering has three color behaviours, depending on the color switch and the palette:

1. No palette, color off. Pure two-tone: ink cells are black, paper cells show the paper color.
2. No palette, color on. The decision is still made in black and white, but ink cells take the original color of that spot in the photo. You get colored dots on paper, like a screenprint.
3. Palette chosen. The algorithm works in full color against the palette colors, and error diffusion spreads the color error, so the palette mixes optically into shades it does not contain. Every cell is painted in its palette color, including light ones, so pale palette entries such as pink, cream or yellow show up exactly as chosen.

In the image editor, pick a palette from the palette button. "No palette" turns palettes off. The list shows these palettes:

Generate from image (the pipette button at the bottom) samples the current output and builds an 8-color palette from it, skipping near-black pixels. It appears in your look as "Aura Gen".

Tip: Palettes with few colors dither most visibly. Error diffusion with a 4-color palette gives the richest texture. Ordered dithering with a 16-color palette gives the cleanest retro look.

A palette is also enforced on the final output of every effect, not just dithering. See palette enforcement.

Why resolution matters

Dithering happens on the working grid, not on your full-size photo. In the image editor the grid is 0.4 x image width x Resolution cells across, and each cell is drawn as a 2 x 2 px dot. The grid is capped at 2,000 cells on the long edge.

For a photo 3,000 px wide:

Every algorithm looks different at each size. Atkinson and Bayer patterns come alive at low resolution, where each dot is visible. JJN and Stucki shine at higher resolution, where their smoothness has room.

When you export, the dither grid is not recalculated. Bitgrain renders the same grid you see and enlarges it with nearest-neighbour scaling, so your export has exactly the dots from the preview, just bigger and still perfectly sharp. That is also why a dither at low Resolution exported at 4x is a crisp pixel-art file rather than a blurry one. See scaling up for export.

Recipes

These use only controls from the image editor. Treat them as starting points.

Classic Mac

1. Click dither and pick atkinson.
2. Turn colorize off. Leave palette on "No palette".
3. In adjust, set Resolution around 60%, Contrast 1.4x, Saturation 0x.

Handheld console

1. Click dither and pick bayer 4.
2. Choose the Gameboy DMG palette.
3. Set Resolution to 25% to 40% so each dot reads as a pixel.

Newspaper photo

1. Pick stucki or floyd steinberg.
2. Turn colorize off, set Contrast to 1.3x.
3. Keep Print finish on in adjust for a paper tone and slight misregistration.

Screenprint in color

1. Pick floyd steinberg with colorize on.
2. Raise Saturation to 1.5x and Contrast to 1.3x.
3. Drop Factor to 70% for flatter, poster-like areas.

Glitchy worms

1. Pick sierra lite or burkes.
2. Push Factor to 180% or more.
3. Try the Vaporwave or Neon palette.

Cyanotype blueprint

1. Pick blue noise.
2. Choose the Cyanotype palette.
3. Set Resolution to 100% and Contrast to 1.5x.

Tip: Save a look you like as a preset so you can reuse it. See presets and recipes.

Related

• Effects overview
• Halftone and print
• Color palettes and LUTs
• Adjustments
• Presets and recipes
• Exporting from the image editor

More documentation

• All documentation
• More in effects
• Open the editor
• Open the studio
• Read the blog