Threshold Image

Thresholding converts an image to pure black and white using a single hard cutoff: each pixel becomes black or white depending on whether its brightness is below or above the midpoint. Unlike dithering, there is no dot pattern - edges are clean and solid, the classic high-contrast line-art look.

A thresholded image is useful for line art, stencils, high-contrast logos, scanned text or a stark graphic style. The output keeps your original format and dimensions - a PNG stays a PNG (with transparency), a JPEG stays a JPEG.

Everything runs entirely locally in your browser on a canvas (no upload, even offline) - your image never leaves your device. Thresholding converts to greyscale first, so colour is discarded; for a softer, shaded black and white use dithering instead. Animated images are flattened to a single frame.

The threshold itself is the boundary on the brightness scale from 0 to 255: everything below it becomes black, everything above it white. A low value leaves more white, a high one more black. Unlike with dithering, no midtones arise - which is exactly what makes the result ideal for line art and cleanly cuttable stencils.

Specifications

In 3 steps

1. Drop or tap your image (PNG, JPEG or WebP).
2. It is converted to greyscale and split into black or white at the midpoint.
3. Download the black-and-white image (several at once as a ZIP).

Limitations: Converts an image to pure 1-bit black and white with an adjustable threshold (default: midpoint 128; no error diffusion, so no dot pattern - clean hard edges). The original format and dimensions are preserved (PNG keeps transparency; JPEG flattens onto white). Colour is discarded. Animated inputs are reduced to a single frame.

FAQ

Related tools

Dither Image · Posterize Image · Grayscale Image · Solarize Image