300dpi is typical for most things that go from graphic designer to professional printer. It should be sufficient for most things. If you're looking for a way t

300dpi is typical for most things that go from graphic designer to professional printer. It should be sufficient for most things. If you're looking for a way to turn a bitmap into a vector type thing, for a plotter or laser or so on, then potrace or the bitmap->vector converter inside Inkscape should be able to do it. They work well for line art.