Colours adjustment with `sane'

[Rodolfo Medina <rodolfo.medina@gmail.com>]

I got not sufficient help from the `sane' mailing list about this problem: I
don't manage to properly adjust colours when scanning a photo with `sane'.  In
particular, I want to diminish the red colour from a photo, but with the
--red-gamma-table option all I get is that red turns to grey and grey turns to
red!  Whereas the --gamma-table option is inactive and I don't manage to
activate it.

Anybody on this list who has experience with this matter?  Or maybe adjust
colours with another application?

Thanks,
Rodolfo