ppmtopgm

Convert color PPM images to grayscale

Convert color to grayscale

$ ppmtopgm [input.ppm] > [output.pgm]

ppmtopgm [file]

ppmtopgm converts PPM color images to PGM grayscale. Uses standard luminance formula to compute gray values. Part of Netpbm toolkit.

sudo apt install netpbm

sudo dnf install netpbm

sudo pacman -S netpbm

sudo apk add netpbm

sudo zypper install netpbm

brew install netpbm

nix profile install nixpkgs#netpbm