Convert formats

Conversion is never quite lossless

Every format encodes different assumptions, and moving between them means deciding what to keep. A PDF fixes each character at a coordinate. An image is a grid of pixels with no notion of a character at all. Converting between them means discarding one model in favour of the other, and something is always lost in the exchange.

That is worth knowing before you judge the output. A page rendered to an image can no longer be searched; text pulled out of a PDF no longer carries its layout. Neither is a fault in the tool. Both are the cost of crossing a format boundary, and the pages here say which cost applies.

Choosing between JPG and PNG

This is the only real decision in the image conversions, and it goes the same way in both directions. JPG compresses by discarding detail the eye is unlikely to miss, which suits photographs and produces small files. PNG discards nothing, which keeps text and line art crisp but produces much larger files on photographic content.

The practical rule: pages of text, tables and diagrams belong in PNG. Pages carrying photographs belong in JPG. Choosing wrongly costs you either visible smearing around letterforms or a file several times larger than it needed to be.

The scanned-document trap

A scan looks like a document but is a picture of one. Nothing in it is text, so a search finds no matches and an extraction returns an empty file.

Every text-based conversion here depends on the PDF actually containing text. If yours does not, the tools will tell you rather than hand back an empty file. Adding a text layer to a scan requires character recognition, which is not offered on this site.