Color mixing
Floyd–Steinberg vs Atkinson dithering
Use Floyd–Steinberg when a gradient has to survive a small palette. Use Atkinson when you want more of the original contrast and you can tolerate a little grain. Turn dithering off when every cell will be a stitch, a bead, or a block you place by hand.
Both methods run after the grid exists. Each cell has an average color. The converter picks the nearest palette color, subtracts, and pushes the error forward. The palette might be 16 source colors, or 16 Pico-8 colors, or 12 floss numbers. Dithering doesn't create colors outside that list. It only arranges the ones you allowed.
Floyd–Steinberg
Floyd–Steinberg sends the error to four neighbors: 7/16 to the right, 3/16 down-left, 5/16 down, and 1/16 down-right. The fractions add to 16/16, so the error is conserved. On a sky that must be only three blues, you get a pepper of those blues instead of two hard bands. That pepper is the point. At width 64 and 8 colors, a sunset usually wants this mode.
The cost is speckle in places you wanted flat. A white wall becomes a mix of white and light gray. A logo's flat red picks up dots along the edge. If you see that, switch to Atkinson or to off. Don't "fix" it by raising the color count to 40. You'll get the photo back.
Atkinson
Atkinson, the dither Bill Atkinson used on the original Macintosh, pushes error to six neighbors and divides by 8, so only 6/8 of the error moves on. The missing 2/8 makes the picture punchier. Highlights stay bright. Shadows stay dark. Flat areas stay flatter because a tiny error dies instead of walking across the wall.
It's the better default for a face at 16 colors when Floyd looks dirty, and for UI icons where a flat fill is part of the design. It's worse for a long smooth sky. You'll see steps again, just softer than dithering off.
Off
Off means nearest color and nothing else. A cell is one stitch. This is what you want on the cross-stitch page and the fuse-bead page. A dithered bead chart looks clever on screen and miserable on a pegboard, because a "skin tone" might be a checker of two bead colors you've to place one by one. If you like the look, export it as pixel art. Don't pretend it's an easy craft pattern.
A test you can run in a minute
Open the pixel converter on the Sunset example. Set width to 48 and colors to 8. Export is unnecessary. Just flip the dither menu through Off, Floyd–Steinberg, and Atkinson without moving anything else.
Off: the sky is bands. Floyd: the sky is mixed and the hill's edge is noisier. Atkinson: the sun stays a cleaner disc and the sky is a bit steppy. None of these is the "correct" sunset. They're three answers to "8 colors isn't enough." If 8 colors is enough for your shape, leave dithering off and spend the time on contrast instead. The muddy conversion guide puts dithering third, after contrast and pixel width, on purpose.
One limit: dithering runs in cell space, not in source-pixel space. A 16×16 sprite has too few cells for the pattern to read as a tone. On a tiny sprite, dithering usually looks like a mistake. Prefer off, and paint the one highlight by hand.
If you're comparing the two dithers for a write-up or a style frame, export both small PNGs and open them at the same zoom. Don't compare a large preview of one against a zoomed screenshot of the other. The large file adds no new colors. It only makes the same cells easier to see. Name them sky-floyd.png and sky-atkinson.png so you don't mix the pair a day later. The legend should list the same hex values in both files when the color cap didn't change. If the hex list changed, a slider moved and the test is invalid.
When dithering makes things worse
Turn it off for beads, cross-stitch, drills, and most chat emotes. Below 24 cells wide, speckle can't average out. Fix contrast and width before you dither mud.
Pick a mode in one minute
Sky or skin in the frame: try Floyd. Logo or emoji: off or Atkinson. Craft export: off, full stop. Still unsure: export three small PNGs at the same settings and compare at 400% zoom. The winner is the one where you can name each flat region without squinting through pepper. For stitch-specific reasoning, read photo to cross-stitch.
Questions
What's dithering here?
When a cell is forced to a palette color, the leftover red, green, and blue error is added to neighboring cells so the average still looks close.
Which dither should I try first?
Floyd–Steinberg, if the picture has a sky, skin, or any smooth shade. Off, if you're making a stitch or bead chart.
Why does Atkinson look harsher?
It only passes on 6/8 of the error. The rest is dropped, so contrast stays higher and some cells never get a speck.
Does dithering add new colors?
No. It rearranges which allowed palette color each cell gets. The legend list stays the same length.
Can I dither only the background?
Not in one pass. Pick off and paint, or export flat for crafts and keep dither for screen-only PNGs from a duplicate tab.
Keep going
Updated 30 September 2026