.TH LUM 9.1
.SH NAME
lum \- compute luminance
.SH SYNOPSIS
.B fb/lum
[
.I input
]
.SH DESCRIPTION
.I Lum
computes the luminance of the input picture using the NTSC formula
.I L=.299R+.587G+.114B.
Pixel values are mapped through the input image's color map, if any.
The resulting image is written to standard output.
.SH "SEE ALSO
.IR picfile (9.6)