pnmgamma

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

• Convert the image from BT.709 luminance to radiance or sRGB luminance:

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

• Convert the image from radiance or sRGB luminance to BT.709 luminance:

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

• Specify the gamma value used for the gamma transfer function:

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

• Specify the gamma value used for the gamma transfer function per color component:

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