[comp.sys.sgi] Black/White inversion of rgb img

deyrau@ciba-geigy.ch (Dipl agr Veronique Eyraud) (08/17/90)

Is there a command somewhere in /usr/sbin allowing to invert the
black and white of a rgb image, and thouse only?
(The invert command, as one can expect, takes all the complementary colors
of the image)

Thanks,