PDFs feel like documents but behave like decks of cards. Each page is its own little stage with its own content, completely independent. Understanding that one fact unlocks most of what makes PDFs odd and powerful.
Each page is self-contained
Unlike Word, where text flows from page to page, a PDF page knows nothing about its neighbours. The content on page two doesn't push to page three when you add a paragraph — there's no flow. This is why editing PDFs feels chunky. The upside: you can reorder, delete, rotate, or split pages without disturbing anything else. They're cards, not chapters.
Pages have fixed sizes
Each PDF page is locked to a specific dimension — A4, Letter, A3, custom. You can mix sizes within one file, which is why combined documents sometimes have a giant page in the middle. Most viewers handle this fine; print results vary. If you're merging files of different paper sizes, expect a slightly jagged result. Tools can normalise sizes during merge if you ask.
Why this design exists
PDF was invented to replace printed paper. The fixed-page model maps directly to physical sheets — same size everywhere, same content everywhere. That's also why PDFs don't reflow on mobile the way HTML does. The trade-off: predictability over flexibility. For documents that genuinely need to look identical on every screen, this is exactly the right model.
FAQ
Can I make a PDF page bigger after the fact?
Yes, but the existing content stays the same size — you just get more whitespace. To truly resize, re-export from the source document with new page dimensions.
Why does my PDF have blank pages?
Usually leftovers from the source document — extra paragraph breaks pushed content over. Easiest fix: delete the blank pages directly in Flint.
Can pages share a header or footer?
Headers and footers are added per-page, not flowed through. Source apps stamp them on each page during export. To add or change them in an existing PDF, use an editor and apply consistently.
Pages are independent — once you see them that way, PDFs make sense. Try shuffling some in Flint to feel how flexible the format actually is.