The Technical Architecture of PDF: A Labyrinth of Objects
Beneath the surface, PDF files are complex compositions made up of objects: text blocks, images, vectors, fonts, metadata, and instructions for rendering. These elements are often stored in fragmented sequences that are optimized for viewing rather than editing. The text is not always stored in logical reading order, and words may be divided into separate character objects placed precisely on the page based on coordinates.
Maybe 10 years ago I was a student of file formats and I actually liked PDF as it had a clear theory of how you serialize a graph of objects. It's more like the old Microsoft Word format or the current DOCX and much better than the atrocious PSD format. PDF is a good format for one developed in the 1990s for what it was intended to do.
Comments
There's a pretty decent explanation here:
https://mailmergic.com/blog/why-pdf-are-hard-to-edit/
The most compelling tidbit I found was this:
Lots more there. No more spoilers.
Maybe 10 years ago I was a student of file formats and I actually liked PDF as it had a clear theory of how you serialize a graph of objects. It's more like the old Microsoft Word format or the current DOCX and much better than the atrocious PSD format. PDF is a good format for one developed in the 1990s for what it was intended to do.