Monitor greyscales

[Bob Courtney]

> 
> To my knowledge, using d.colormode float you should be able to display a lot
> more greyscales, although I don't know if there will be 256 of them.
> 
> Philip Verhagen

Be aware that many window managers reserve some colours that cannot be
accessed by the monitor. On my HP 9000/720 for example, I can only
set 190 or so colours out of the possible 256. If an image has more
than 190 colours on my system, then the default colour map is used
which only allows 5 or 6 grey shades. The default pallette is
particularly odious for grey scale images.

So the best best is to reclassify the image to contain, say, 100 grey
scale colours ( you can't discern more gradations for most
images) and use "d.colormode float".

Bob Courtney
Atlantic Geoscience Centre.