pnmgamma
Apply gamma correction to PNM images
TLDR
Apply gamma correction
$ pnmgamma [gamma] [input.pnm] > [output.pnm]
Brighten image$ pnmgamma 2.2 [input.pnm] > [output.pnm]
Darken image$ pnmgamma 0.5 [input.pnm] > [output.pnm]
Per-channel gamma$ pnmgamma [r_gamma] [g_gamma] [b_gamma] [input.pnm] > [output.pnm]
SYNOPSIS
pnmgamma [options] gamma [file]
DESCRIPTION
pnmgamma applies gamma correction to PNM images, adjusting the brightness curve by raising each pixel value to a power function. Values greater than 1 brighten the image while values less than 1 darken it.
Per-channel gamma values can be specified separately for red, green, and blue. The -ungamma option reverses a previously applied gamma correction. Part of the Netpbm toolkit; superseded by pamgamma.
PARAMETERS
GAMMA
Gamma correction value.FILE
Input PNM file.-ungamma
Remove gamma correction.-cieramp
Use CIE luminance ramp.
CAVEATS
Values >1 brighten, <1 darken. Part of Netpbm suite.
HISTORY
pnmgamma was created as part of Netpbm for gamma correction operations.
