We need more information as to OS (not that important), printer (very
important) and printer driver (also very important). If you are sending
the pdf to inkjet printer it frequently has to rasterize (convert to
dots) all of the information contained in the file.If it is a 3 or 4
color printer using 24 or 32 bits for each dot on the page and you are
printing at 600 or 1200 dpi much higher you are going to find yourself
with a very very large file.