|png-bw [-ntsc] [-crt] [-R [num]] [-G [num]] [-B [num]] [in.png] > out.bw|
Pix-bw will convert a PNG format file from its standard input and produce a black and white bw(5) file on its standard output, If the PNG file contains a B/W image the conversion is direct, however, if the PNG file contains a color image, then by default all three colors are weighted equally. The -ntsc uses weighting based on the NTSC primaries and the D6500 alignment white. The -crt flag applies weights for "typical" CRT phosphor chromaticities and the D6500 white.
Individual color plane(s) can be selected via the -R -G and -B flags. If one or more of these flags is followed by a value, the value will be treated as a weight to be applied to that color This value is implicitly 1.0 divided by the number of colors selected for the flags which are not followed by a value.
png-bw -R -B < file.png > file.bw will equally blend the red and blue color planes.
png-bw bw_file.png < file.bw will convert a b/w PNG file to bw(5) format.
png-bw -R0.30 -G0.59 -B0.11 < file.png > file.bw has the same effect as the -ntsc flag. [The -crt weights are: 0.26, 0.66, 0.08]
brlcad(1), png-pix(1), bw-png(1), pix-png(1), pix(5), bw(5).
John R. Anderson
This software is Copyright (c) 1998-2013 by the United States Government as represented by U.S. Army Research Laboratory.
Reports of bugs or problems should be submitted via electronic mail to <firstname.lastname@example.org>.