I am generating two plots. One has 11,001 data points on a 2D plot with 23 different polynomial curve fits, each curve fit uses all 11,001 abscissas. The other plot has 11,001 data points with a single polynomial curve on top that again uses all 11,001 abscissas. When I save the latter plot as a PDF file, it is a gorgeous vector graphic that I can mess with in Adobe Illustrator. When I save the former plot as a PDF file it is always bitmapped and looks terrible. I have tried EPS and I get the same thing for both plots. Why is this happening and how do I get a non-bitmapped plot for the former plot?