"Vague" lines

Hi list, I have created plots, but I find the line style is

    > a bit "vague". The line isn't one sharp, contrasting color,
    > but smoothly blended to the background. Is the correct term
    > anti aliasing?

Yes.

    > When setting the linestyle to 'dotted', the plot is not very
    > clear, see the following result:
    > http://vankuik.nl/cgi/wiki.cgi/download/vague_dotted_plot.png

Try turning antialiasing off for certain lines with

  ax.plot(x,y,antialiased=False)

or globally with the lines.antialiased rc parameter; see
http://matplotlib.sf.net/matplotlibrc

JDH