Halftone image
Classic newsprint-style dot halftone, on your device.
Runs on your device. The file is never uploaded.
Halftone image divides the picture into 8 pixel square cells and measures the average brightness of each. It then draws a black circle at each cell's centre, its radius growing as the cell darkens. Cell size accepts nothing below 2. Each pixel ends on pure black or pure white, so this is one screen rather than a CMYK separation.
Questions
What does the halftone look like?
A single black dot screen on white, in the style of newsprint. The image is divided into square cells, the average brightness of each cell is measured, and a black circle is drawn in the middle of that cell whose radius grows as the cell gets darker. A fully black cell fills the square; a white cell draws nothing.
What does the cell size option control?
Dot grid cell size in pixels, default 8, is the width of one screen cell. Smaller numbers give finer, denser dots that keep more of the picture; larger numbers give a coarser, more obviously printed look. The minimum is 2, and anything below or any fractional value stops with "cellSize must be a whole number of 2 or more".
Is the result in colour?
No. Every output pixel is pure black or pure white, so colour and gray tones are gone. This is one screen at a fixed grid, not a CMYK separation, and there are no angled screens, no rotated cyan, magenta, yellow and black plates, and no dot shape choice. Alpha is copied from the input, so transparent areas stay transparent.
Why does my halftone look muddy after saving?
Hard black dots on white are hard for JPEG, which adds ringing around every edge. The output keeps your input format and encodes JPG and WebP at the Quality option, default 80. Feed it a PNG, or convert the result with Convert image, to keep the dots crisp.
Does anything leave my device?
No. The image is decoded, screened and encoded in a Web Worker in this tab with the jSquash codecs. Nothing is uploaded and no account is needed. The output is named with a -halftone suffix in the original format, and you can drop several files at once.