PDF Tools

Almost everything here edits the PDF’s structure rather than its contents. Merging, splitting, reordering, rotating and deleting pages copy the original page objects across untouched, so text stays selectable, vectors stay sharp and the file quality is byte-for-byte what you started with. If a tool is doing one of those jobs, there is no quality decision to make and nothing to trade away.

Compression is the exception, and it is worth understanding why. A PDF that is large because it contains scanned images can only be shrunk by re-rendering those pages at a lower resolution — which turns the text in them into part of the picture. That is why Compress PDF warns that text stops being selectable. A PDF that is large because it contains a lot of real, selectable text is usually already close to its floor, and compressing it will cost legibility without saving much.

So the first question is what is making your file big. If it came from a scanner or a phone camera, compression will help enormously. If it came from a word processor, splitting out the pages you actually need will help more.