Image to Black and White Converter

How to use

1. 1Drop an image into the upload area or click Choose file. PNG, JPEG, WebP, BMP, and GIF are supported up to 25 MB and 8192x8192 pixels.
2. 2Pick a conversion mode: Grayscale keeps a full tonal range; Black and white (1-bit) quantizes every pixel to pure black or pure white.
3. 3Choose the grayscale method. BT.709 is the default for photos; BT.601, Average, and Lightness change how channel brightness is weighted before the conversion.
4. 4For 1-bit output, pick a dithering algorithm (None, Floyd-Steinberg, Atkinson, or Bayer 4x4) and drag the Threshold slider to set where the cut between black and white falls.
5. 5Use the Brightness bias slider to lift dark sources or pull down washed-out ones, and toggle Invert if you want light and dark swapped.
6. 6Choose an output format (PNG, JPEG, or WebP) and quality if relevant, then click Convert and download to save the result at the original resolution.

About this tool

Image to Black and White Converter turns any color image into a clean grayscale or a true 1-bit black and white image, with the math used by the conversion shown alongside every choice. The tool runs entirely on a local canvas: the file is loaded into an object URL, every pixel is processed by getImageData and putImageData, and the result is downloaded as a Blob. Nothing is uploaded. Grayscale mode offers four named methods so the result matches what other software produces: Luminance BT.709 (0.2126 R + 0.7152 G + 0.0722 B) for modern sRGB and HDTV, Luminance BT.601 (0.299 R + 0.587 G + 0.114 B) for the older NTSC weighting most editors used last decade, Average for an equal-weight (R + G + B) / 3 conversion, and Lightness for the HSL (max + min) / 2 method that gives a softer look. Black and white (1-bit) mode applies a threshold to the grayscale value and quantizes every pixel to pure black or pure white. The threshold slider runs from 0 to 255 with 128 as the neutral midpoint, and four dithering algorithms cover the common cases: None for a stark high-contrast silhouette, Floyd-Steinberg for the classic 7/16, 3/16, 5/16, 1/16 error diffusion used in photo prints, Atkinson for the higher-contrast original Macintosh diffusion that loses 1/4 of the error on purpose, and Bayer 4x4 for an ordered dither that produces a clean repeating pattern. A brightness bias slider lifts or pulls midtones before grayscale or threshold is applied, useful when the source is too dark or washed out, and an Invert toggle swaps light and dark for negative-style output. The live preview is rescaled to fit the panel so updates are instant, but the final download is rendered at the full source resolution, with PNG (lossless), JPEG, and WebP outputs and an adjustable quality slider for JPEG and WebP. Useful for laser engraving artwork, e-ink display assets, screen-printing source files, zines and risograph layouts, accessible high-contrast versions of marketing imagery, photographic black and white edits, badge and logo preparation, and any workflow that needs a predictable, fully local grayscale or monochrome conversion.

Free to use. Works in your browser. No signup, no login.