When you increase the resolution of a PDF file, the file is more precise, but the
file size is also larger.

When you create PDF files intended for printing from Adobe Reader, select a resolution
to match the output of your plotter or printer. High resolutions (over 2,400 dpi)
are for viewing. For example, when you create PDF files of drawings that contain a
lot of detail, such as a topographical map of a large region, use a higher resolution
setting for greater detail in the PDF file. As you increase the resolution setting,
raster image quality increases, the speed of printing decreases, and memory requirements
increase.

Vector quality

Specifies the resolution (in dots per inch) for vector graphics and gradients for
PDF files.