quality="/printer"
#Possible values are:
#/screen   (screen-view-only quality, 72 dpi images)
#/ebook    (low quality, 150 dpi images)
#/printer  (high quality, 300 dpi images)
#/prepress (high quality, color preserving, 300 dpi imgs)
#/default  (almost identical to /screen)

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=$quality -dNOPAUSE -dQUIET -dBATCH -sOutputFile="build/Dissertation_Daniel_Berninghoff.pdf" build/main.pdf