PDF compression
PDF compression is not magic. Some PDFs are already optimized, some are mostly vectors or fonts, and some cannot shrink much without damaging readability. Diagnose the file before assuming a second compression pass will help.
Details
If the source already uses compressed streams, optimized images, object streams, or linearized output, there may be little safe size reduction left. Recompressing repeatedly can lower quality without meaningful savings.
Scans, photos, and image-heavy reports usually offer the most size savings, but they also carry the highest visual-quality risk. Check image density and review the compressed output before sharing.
Removing metadata can make a sharing copy cleaner, but it rarely solves large-file problems by itself. Compression, page splitting, image preparation, and output format choices address different parts of the task.
If the file is too large because it contains unnecessary pages, hidden attachments, repeated scans, or oversized source images, organize or rebuild the packet first. Compress only after the final copy is assembled.
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