Clean lines?

Hi. I'm restricted to free software online. I've primarily been using Serif Photoplus 6. The problem is that i can't adjust my scanned art to appear as clean as it could be. I go through all the equalization, contrast, and threshold filters but regardless the lines never are consistent.
I really would like to produce decent lineart as I think it would greatly enhance the quality of my work. Anyone know of any free software that can produce really nice, neat lineart?

Have you tried scanning it in at high resolution? I found that scanning stuff in at 300 dpi (Dots Per Inch) looks a lot better than, say 150 or 200. That would be the first step I'd suggest.

i actually do scan at the highest resolution possible. I then do a series of filters to enhance the outline. When I get to making the lines all solid black though its never consistent around the art and i have to doctor it until it looks reasonable. I really just envy lineart that looks pristine and was wondering if its a software issue.

OK, I follow you. I've noticed that too with my own stuff. I always thought it was just me. Now you have me curious!