Free web tool
Convert an image to black and white using a configurable threshold, with optional inversion.
Convert an image to black and white by splitting luminance at a threshold. It is useful for scans, line art, and quick checks of where an image separates into light and dark regions.
The tool does not use a simple average of R, G, and B. It calculates luminance with standard weighting that gives green more influence and blue less.
That produces a split that is usually closer to perceived brightness. Raising the threshold makes fewer pixels qualify as white.
Fully transparent pixels can still contain hidden RGB values. Counting those values in the white-pixel percentage can make the number disagree with what you see.
In v1.49, fully transparent pixels are excluded from the white-share denominator and reported separately. The original Alpha values are preserved.
A two-color PNG is still an image. Text does not become searchable text, and lines do not become editable SVG paths.
Use OCR when you need text recognition, and vector tracing when you need editable paths.
If black and white removes too much information, Image posterize reduces tonal levels while retaining RGB color.
Decide first whether you want “shape in two colors” or “flatter color regions.” That usually makes the tool choice obvious.