The PDFDad blog
Practical guides to working with PDFs, written by the people who build the tools. We explain what actually happens to your file, including the parts other guides leave out.
Splitting, Extracting and Reordering: Taming a Large PDF
Four operations do almost all the work of reorganising a document. Here is which one to reach for, how page ranges behave, and the order that avoids counting pages twice.
GuidesHow to Merge PDF Files Without Uploading Them
A practical guide to combining PDFs: getting the page order right, what merging keeps and loses, handling locked files, and why the upload step is worth avoiding.
GuidesUpload or In-Browser? What Happens to a PDF You Hand to a Website
Most online PDF tools send your file to a server. Here is what that involves, why browsers can now do the work locally, and how to check for yourself which kind you are using.
GuidesWhy PDF Files Get Corrupted, and What Repair Can Actually Recover
Interrupted downloads, broken cross-reference tables and truncated writes all produce a file your reader refuses to open. Here is what goes wrong inside, and how much of it is fixable.
GuidesWhat Flattening a PDF Actually Does (And When You Need It)
Forms, comments and signatures live in a layer above the page until you flatten them. Here is what that step changes, what it permanently removes, and the four times you should always do it.
GuidesWhat Your PDF Quietly Reveals: A Guide to Document Metadata
Author names, software versions, creation dates and old filenames travel inside every PDF you send. Here is what is stored, how to see it, and what to clear before a file leaves your hands.
GuidesHow to Sign a PDF: Electronic Signatures vs Digital Signatures
Pasting an image of your signature and cryptographically signing a document are two different things. Here is what each one proves, when either is enough, and how to sign without an account.
GuidesJPG or PNG? Choosing a Format When You Export PDF Pages
One is lossy and small, the other lossless and sharp. Which you want depends entirely on what is printed on the page — here is how to decide in about five seconds.
GuidesPDF Passwords Explained: Open Passwords, Permissions and Real Encryption
A PDF can have two different passwords that do two very different jobs. Here is what each one protects, why one of them can be removed in seconds, and what AES actually does to your file.
GuidesOCR Explained: How a Scan Becomes Searchable Text
What optical character recognition does to a scanned page, why 300 DPI matters more than megapixels, which characters get confused, and how a searchable PDF is put together.
GuidesWhy PDF to Word Conversion Is Never Perfect
PDFs store positioned glyphs, not paragraphs. Here is what a converter has to guess, why tables and columns break, and how to get the cleanest result from the file you have.
GuidesHow to Compress a PDF Without Wrecking It
Why PDFs get large, which compression settings actually matter, when a file simply will not shrink, and how to hit an email size limit without turning your document to mush.
GuidesWhat PDF Redaction Really Means (And Why Black Boxes Fail)
Drawing a black rectangle over text does not remove it. Here is how PDF redaction actually works, how leaked documents get un-redacted, and what to check before you send a file.
Looking for something specific?
These guides cover the thinking behind the tools — what a PDF actually stores, what each operation permanently changes, and the mistakes that are easy to make. If there is something you would like explained, tell us.
Browse all 30 tools