for white on black ps-print generates white on white text

[Jens Petersen]

To reproduce:

% emacs -q
 M-x set-foreground-color RET white RET
 M-x set-background-color RET black RET
 C-x C-f /usr/include/stdio.h
 C-u M-x ps-print-buffer-with-faces RET ~/tmp/psprint.ps RET y
 C-x C-c
% gv ~/tmp/psprint.ps

and observe that the default font with white foreground is rendered
white on white in the ps file.

Setting
(setq ps-default-fg "black"
      ps-default-bg "white")
doesn't seem to help.

-Jens

ps This was reported a good while back at
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=75763