Compress a PDF for Print Without Losing 300 PPI

Four things, and only one of them is about file size. The authoritative numbers are not a matter of opinion: Adobe ships them as plain-text preset files that Distiller and the Creative Cloud applications read, and you can open them.

ls "/Library/Application Support/Adobe/Adobe PDF/Settings/"
# High Quality Print.joboptions   Press Quality.joboptions
# Smallest File Size.joboptions   PDFX1a 2001.joboptions  …

So, in plain terms:

• 300 PPI at final size. Not 300 PPI in the original photograph. What matters is the resolution across the inches the image occupies on the printed sheet.
• Every font embedded and subsetted. A missing font is not a quality problem, it is a reprint.
• The color space the press expects. [Press Quality] converts to CMYK; [High Quality Print] leaves color alone for a desktop printer or proofer that manages its own conversion. Ask which one your printer wants rather than guessing.
• Bleed, if anything runs to the edge. Compression does not touch bleed or trim boxes, but a compressor that rebuilds the document can drop them. Check the output with pdfinfo -box file.pdf, which prints MediaBox, CropBox, BleedBox, TrimBox and ArtBox. mutool info only reports media boxes, so it will not catch this.

One detail out of those files that catches people: [Smallest File Size] sets EmbedAllFonts to false. Adobe’s own description of that preset is “best suited for on-screen display, e-mail, and the Internet,” and it means exactly what it says. It is not a print preset and it never was.

One command, and it reports effective resolution rather than raw pixel count, which is the number that matters:

pdfimages -list artwork.pdf

The x-ppi column is the resolution of each image at the size it is drawn on the page. Two of our test files make the point:

Same source photographs, three completely different answers. That is why “which preset should I use for print” has no universal answer and why anyone who gives you one has not looked at your file.

Because they cap pixels and a printer cares about inches. A pixel ceiling produces whatever resolution the page geometry happens to yield, and on a large page that number collapses.

Here is the same tool, the same five presets, run across two documents. Our presets are long-edge pixel caps of 600, 900, 1,200, 1,800 and 2,400 pixels:

Medium leaves 68 PPI on one document and 344 PPI on the other. On the layout it is genuinely press-viable. On the brochure it is a photocopy. Nothing about the preset name tells you which one you are getting, and this is the single most important thing to understand before compressing anything destined for paper.

Preview’s Reduce File Size has the same shape of problem with the dial welded shut. Its filter hard-codes 144 DPI and an absolute ceiling of 2,400 pixels per image, whatever the page size:

We take that filter apart properly in why Preview’s Reduce File Size ruins PDFs. For print work the summary is short: do not use it.

Two moves, in this order. Both were run on the same files as everything above.

1. Re-encode without resampling. If the PDF carries uncompressed or Flate-encoded images, which is common in exports from drawing tools and anything with pasted screenshots, you can convert them to JPEG with the pixel dimensions untouched:

qpdf --optimize-images artwork.pdf artwork-smaller.pdf

On a two-page file with Flate-encoded 2,550 × 3,300 images that took 19,873,274 bytes to 1,989,730 bytes in 0.33 seconds, still 2,550 × 3,300, still 300 PPI. A 90% saving with zero resolution change is as close to free as this gets, and it should be the first thing you try.

2. Downsample to exactly 300 PPI, and only above 300. Ghostscript with explicit parameters rather than a named preset:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.6 \
   -dDownsampleColorImages=true \
   -dColorImageDownsampleType=/Bicubic \
   -dColorImageResolution=300 \
   -dColorImageDownsampleThreshold=1.0 \
   -dDownsampleGrayImages=true \
   -dGrayImageDownsampleType=/Bicubic \
   -dGrayImageResolution=300 \
   -dGrayImageDownsampleThreshold=1.0 \
   -dAutoFilterColorImages=false -dColorImageFilter=/DCTEncode \
   -dEmbedAllFonts=true -dSubsetFonts=true \
   -dNOPAUSE -dQUIET -dBATCH \
   -sOutputFile=print-ready.pdf artwork.pdf

That is the behaviour you want from a print tool. It removes what is redundant and declines to touch what is not. Note the DownsampleThreshold of 1.0: Ghostscript’s default of 1.5 means a named preset like /prepress ignores anything under 450 PPI, which is why running it on our 342 PPI brochure changed the file by −0.0%. Adobe’s presets carry the same 1.5 threshold, and this is the usual reason “I used Press Quality and it is still huge.”

The full set of terminal recipes, including the grayscale and color-conversion flags, is in compressing PDFs from the Terminal on macOS.

This is our tool, and for press work there are three cases where it is the wrong one. We would rather write them down than have you find out at the proof stage.

Full-bleed pages at A4 or larger. Our presets are pixel caps, and 2,400 pixels is the ceiling. On a full-bleed A4 page that is 137 PPI, and on a 24 × 36 inch poster it is 67 PPI, which is the same ceiling Preview hits and for the same reason. If the artwork bleeds and the page is big, use the Ghostscript command above or send the file as it is.

Anything that has to be CMYK or PDF/X. We do not convert color spaces, attach output intents or enforce a PDF/X profile. Our outputs stay in the color space they arrived in. If the spec says PDF/X-1a with a SWOP output intent, that is an export setting in the application that made the artwork, not a compression step.

When the images are already at or below 300 PPI. There is nothing to win, and original is not a no-op: it re-encodes and resamples anything above 2,400 px. If pdfimages -list shows you are already near target, the correct action is to do nothing. The preset breakdown covers what each level does in detail.

Where we are a good fit for print-adjacent work: proofs, client review PDFs, and the folder of one-off exports that has to go out by email today while the press file stays untouched on disk. For that, $29 once and a resolution ladder beats one button, and the file never leaves your machine. If the export itself is the problem, start with why your InDesign PDF export is enormous instead of compressing after the fact, and the five-method comparison has the screen-side numbers.

Run on 26 September 2026 on a MacBook Pro (Mac14,9), Apple M2 Pro, 16 GB of RAM, macOS 27.0 (build 26A428). Sizes are raw bytes from stat -f%z; resolutions from pdfimages -list (poppler 26.04.0). Ghostscript 10.07.0, qpdf 12.3.2, Smol 1.0.35.

Fixtures. Three files built for this article so the results are reproducible. An eight-page A4 brochure with full-bleed images, and a twelve-page layout with twenty-four placements in 88 mm and 54 mm frames, both rendered by headless Chrome from eight synthetic 6,000 × 4,000 photographs generated with ImageMagick 7.1.2. A 24 × 36 inch poster page built from the same source at 134 PPI. No client artwork and no third-party photography was used.

Adobe preset values were read from the .joboptions files Adobe installs in /Library/Application Support/Adobe/Adobe PDF/Settings/, not from documentation. Those files are plain text and self-describing; each one carries Adobe’s own description string alongside the numbers.