Compression reduces file size, mostly by re-encoding images, since images are almost always the bulk of a PDF. There is a trade-off against quality, and the right setting depends on whether the file will be read on screen or printed.
Compression works mainly by re-encoding images. A text-only PDF is already small and will barely shrink, however hard you compress it.
Heavy compression softens scanned text. Always open the compressed file and read a page at full zoom before deleting the source.
Compression re-encodes the page images but leaves any searchable text layer intact, so a compressed scan stays searchable.
A document scanned in colour that only contains black text will shrink dramatically. Scanning in greyscale at 300 DPI avoids the problem at source.
Compression is not always the right answer. If the file is large because it contains pictures you do not need, Remove Images is more effective and lossless for the text. If it is large because it is simply long, Split by Size or Count gets you under an upload limit without degrading anything. Compress when you need the whole document, at smaller size, and can accept some loss in the images.
Image-heavy scans often drop by 50 to 90 percent. Text-only PDFs are already small and compress little.
Real text is unaffected. Scanned pages are images, so heavy compression softens them. Check before committing.
It was probably scanned at high DPI in colour. Greyscale at 300 DPI is usually enough for text documents.
No. The text layer is preserved.
Image-heavy scans commonly drop by 50 to 90 percent. PDFs that are mostly real text may shrink by only a few percent, because there was little to remove.
Text drawn as text is unaffected at any compression level. Scanned pages are images, so they soften as compression increases.
Almost always because it was scanned in colour at a high DPI. A text document rarely needs more than greyscale at 300 DPI.
No. The text layer added by OCR is preserved.
Remove the password first, compress, then re-protect it if you still need encryption.
These tools handle one document at a time. When the job is thousands of files, Greenbooks handles document digitization as a managed service, including bulk scanning, OCR and metadata capture, with the output loaded into DocuVenta DMS. Talk to us about volume work.
