Are you talking about on screen or on your printout? I find that a 1 mil line on my 600 DPI laser printer is almost unreadable. If I fax the printout anythin less than about 12 points has a great chance to be lost. If it is on screen go to the Preferences and turn on the Zoom Line Thickness option. This will show the actual set line thickness as you zoom in. This will give you a better idea of how the printout will look. Remember, the screen has a resolution of between 1/72 and 1/100 inch. A