pnmgamma

Perform gamma correction on PNM images. More information: https://netpbm.sourceforge.net/doc/pnmgamma.html.

pnmgamma -bt709tolinear|bt709tosrgb path/to/image.pnm > path/to/output.pnm

pnmgamma -lineartobt709|srgbtobt709 path/to/image.pnm > path/to/output.pnm

pnmgamma -gamma value path/to/image.pnm > path/to/output.pnm

pnmgamma -rgamma value -ggamma value -bgamma value path/to/image.pnm > path/to/output.pnm