20 guides on how PDF documents actually work — why a conversion loses formatting, why a search finds nothing in a scan, what travels inside a file you send. Each one explains the mechanism first, then what to do about it.
What a PDF actually is, how it stores content, and how to tell one kind of PDF from another.
A PDF is a description of where marks go on a fixed-size page, not a document that reflows — which is exactly why it survived thirty years of format churn.
Use Word while a document is still being written, and PDF once it is finished — the formats are built around opposite assumptions about change.
Try to select a word. If the cursor sweeps across the page without highlighting anything, you have a scan and need OCR before anything else will work.
Modern browsers can parse, render and rewrite PDFs at usable speed, which removes the upload step for most everyday tasks — but not for all of them.
Merging, splitting, extracting, reordering and cleaning up the page structure of a document.
Merging copies pages between documents without re-encoding them, so quality never changes — the things that go wrong are order, orientation and mixed page sizes.
Split when you need many files, extract when you need one smaller file, and remove when you want the original minus a few pages.
Capture consistently, fix orientation before merging, then compress and OCR once at the end rather than per file.
PDF to Word, images to PDF, PDF to JPG or PNG — what survives a conversion and what does not.
A PDF stores positioned glyphs, not paragraphs — so conversion has to infer structure that was discarded when the PDF was made, and inference is imperfect.
JPG for pages that are mostly photographs, PNG for pages that are mostly text and line art — and set the resolution from where the image will be used.
Each image becomes one page, so the decisions that matter are page size, orientation and how much resolution you keep.
Turning photographs of text into searchable, selectable characters — and why accuracy varies so much.
OCR reads pixels and writes characters into an invisible layer behind the page image — the picture you see never changes.
Recognition accuracy is set by resolution, contrast and straightness — fix the capture and the results improve far more than changing tools ever will.
Metadata, redaction, signatures and the checks worth running before you send a sensitive document.
A PDF carries author names, software fingerprints, timestamps, and sometimes earlier versions of its own content — none of it visible when you read the pages.
Drawing a black rectangle hides text from your eyes while leaving it fully recoverable in the file — real redaction has to remove the underlying content.
A drawn signature is a picture on a page — fine for everyday consent, but it proves nothing cryptographically about who signed or whether the document changed.
Five checks, in order, that catch the overwhelming majority of accidental disclosures — each takes under a minute.
End-to-end recipes: preparing files for email, upload limits, printing, and paper-to-digital archives.
Scan at 300 DPI in greyscale, fix orientation and margins first, recognise once, then name files so you can find them without opening them.
Most attachment failures are one oversized scan or one uncompressed image — find the cause before compressing the whole document.
Convert everything to PDF first, standardise page size and orientation, then merge — combining in the wrong order creates most of the mess.
File size is almost always images. Find out whether your PDF is text or scan first, because compression helps enormously with one and does nothing for the other.