R help - Dec 2004 - FW: Unsightly lines from x*y grid in levelplot with Postscript

> One typical problem with gv is that some artifacts show up (which may 
> not be what you describe) when the display is anti-aliased. Try 
> turning that off (by pressing 'a') and see if that improves the 
> display.
> If you produce PDF, it's possible to just turn off antialiasing for 
> "line art", so the text doesn't go chunky.
Sorry, I should have said this is a Ghostview thing.

A summary of the suggestions from Deepayan and Paul:

Pressing "a" does fix the problem in Ghostview by turning off the
anti-aliasing.  It can also be done from the menu under "State."
 
In Adobe Acrobat Reader 5.0, on the Edit menu, in the Preferences 
dialog, in the Display panel, there are three smoothing checkboxes
(one for text, one for line art, and one for images).

None of this matters for printing, where the white lines will not
show up.

--Scott Waichler