Is my file uploaded to a server?

No. This tool runs entirely in your browser via WebAssembly — your file never leaves your device. You can verify this in your browser's DevTools Network tab.

Why does the file change after grayscale?

Each page is re-rendered as a grayscale image, so text becomes part of the image and is no longer selectable — the same trade-off as heavy compression.

Is colour really removed?

Yes — every pixel is converted to its grayscale luminance, so the output prints cleanly in black and white.

Grayscale PDF

Convert every page to black and white — ideal for printing.

Local processing — your files never leave your browser