The Ultimate Guide to PDF Compression Levels
Screen, eBook, Printer, Prepress — what do these PDF compression presets actually mean? A technical breakdown of when to use each.
If you've used Ghostscript, Adobe Acrobat, or any serious PDF compressor, you've seen the presets: Screen, eBook, Printer, Prepress. These originate from Ghostscript's -dPDFSETTINGS flag and have been adopted by virtually every PDF tool. Most people pick one and hope for the best. Here's what they actually do.
What PDF Compression Actually Compresses
Most PDF file size comes from embedded images — rasterised photos, scanned pages, graphics. PDF compression works by:
- 1.Downsampling embedded images to a lower DPI target
- 2.Recompressing image data as JPEG at a lower quality
- 3.Flate-compressing text streams and vector data (lossless)
- 4.Removing embedded font subsets that aren't needed
- 5.Stripping metadata, form XObjects, and container overhead
The Five Presets, Explained
/screen — Maximum Compression
Target: 72 DPI, JPEG ~35 quality. Aggressively downsizes all images. Use when: on-screen reading only, or when file size is the only constraint. Not suitable for printing — text may look pixelated and photos show visible artefacts at 1:1 zoom.
/ebook — The Sweet Spot
Target: 150 DPI, JPEG ~60 quality. The recommended setting for most use cases — email, web upload, internal sharing. Text is crisp on screen and prints acceptably on standard office printers at normal reading distance.
/printer — High Quality
Target: 300 DPI, JPEG ~80 quality. For documents that will be professionally printed but don't require colour accuracy. Photos look sharp; line art is clean. File sizes are 2–5× larger than /ebook.
/prepress — Publication Quality
Target: 300 DPI with lossless compression where possible. Colour profiles are embedded and preserved. For sending to a print shop or publisher. Largest file sizes.
For scanned PDFs (images of pages), /ebook gives a 60–80% size reduction with no visible quality loss at normal reading zoom. For PDFs from Word or InDesign with vector content, the reduction is smaller — typically 20–40%.
Choosing the Right Level
- ●Email attachment (under 5 MB): /screen or /ebook
- ●Website download: /ebook
- ●Office printing: /printer
- ●Commercial printing / publisher submission: /prepress
- ●Archive with unknown future use: /printer or /default
# Ghostscript — free, cross-platform
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.5 \
-dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH \
-sOutputFile=compressed.pdf input.pdfTry our PDF compressor with adjustable quality settings, processed entirely in your browser.
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