[newbie] Increasing Print Darkness

[Han2097]

How do I change the darkness of printed documents?  Papers come out about half as dark 
as they should be.  (It works fine in Windows, so it's not my printer).  I've played 
around with CUPS and not seen anything worthwhile in there.  My printer is an Epson 
Stylus Color 600, if that makes any difference...

TIA

Dan