DITHER
☞ runs entirely in your browser — nothing is uploadedDrop your image here
or click to browse — JPG, PNG, WebP
Dither preview
OneImageTool
Free Image Tools
DITHER
Reduce a photo to pure black and white with Floyd–Steinberg error diffusion — the 1-bit look of early screens and laser prints.
or click to browse — JPG, PNG, WebP
Dither preview
two colours, and the rounding error passed along
Rounding every pixel to the nearer of black and white on its own gives you a blotchy mess: whole regions land on one side and the midtones disappear. Floyd–Steinberg fixes that by refusing to throw the rounding error away. Each pixel is rounded, and the difference between what it was and what it became is handed to the neighbours that have not been decided yet — seven sixteenths to the right, and the rest spread across the row below. The errors cancel over a small area, so the average brightness survives even though every single pixel is one of two values.
The pattern only means something if you can see it. On a four-thousand-pixel photo a pixel-by-pixel dither is averaged straight back into flat grey the moment the picture is displayed at screen width, and the result looks identical to the original. So the error diffusion runs on a grid whose cells scale with the image, and each decided cell is painted as a block. The file keeps its original dimensions; the texture stays visible.
three steps
A JPG, PNG or WebP. Photos with a broad range of tones show the diffusion pattern best.
The grid is derived from the image, so there is nothing to set — the preview is the finished result.
Save as PNG. A two-colour image is exactly what PNG compresses well and what JPG turns into grey mush.
quick answers
An error diffusion algorithm from 1976. Each pixel is rounded to the nearest available colour and the leftover difference is pushed onto neighbouring pixels that have not been decided yet, so the error averages out instead of accumulating.
A halftone keeps a fixed grid and varies the size of each dot. Dithering keeps the dot size fixed and varies how many dots land in an area. Halftone looks like newsprint; dithering looks like an early monochrome screen.
On purpose. A pixel-fine dither on a large photo is invisible once the picture is scaled to fit a screen — the display averages it back to grey. The cells scale with the image so the texture survives being looked at.
Not here; this filter is deliberately one bit. If you want a reduced but still coloured palette, the GIF tools quantise to a chosen number of colours instead.
As a PNG, usually yes and often by a lot, because there are only two values to store. As a JPG it can get larger — JPG is built for smooth gradients and a dither pattern is the opposite of that.
No. The picture is reduced to grey first and then to black and white. That is what makes it a 1-bit image.
No. The picture is decoded and converted inside your browser, and the download is built on this device. There is no server in this tool to receive an image.
Yes — free, with no watermark and no sign-up.