Set the resolution (in dots per inch) for raster images for PDF files.
When you set a higher resolution, the file is more precise, but the file size is also larger.
When you create PDF files intended for plotting, 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.