How To Decrease the Size of a PDF File

You can decrease the size of an pdf file with using gs command. It has lots of options and some of them are described in the example below.

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

Example

Compression’s results of 17.7 MB pdf file are as follows

# -dPDFSETTINGS=/default: selects output intended to be useful across a wide variety of uses, possibly at the expense of a larger output file
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/default -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.default.pdf input.pdf
# 17.9 MB

# -dPDFSETTINGS=/prepress: output similar to Acrobat Distiller "Prepress Optimized" setting (300 dpi)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/prepress -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.prepress.pdf input.pdf
# 17.9 MB

# -dPDFSETTINGS=/printer: selects output similar to the Acrobat Distiller "Print Optimized" setting (300 dpi)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/printer -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.printer.pdf input.pdf
# 17.9 MB

# -dPDFSETTINGS=/ebook: for better quality, but slightly larger pdfs. (150 dpi)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.ebook.pdf input.pdf
# 6.3 MB

# -dPDFSETTINGS=/screen: lower quality, smaller size. (72 dpi)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.screen.pdf input.pdf
#  2.4 MB (bad quality, not usable)