PDF guides

Practical answers to common PDF problems, with the free tools to fix them.

• How to reduce a PDF's file sizeWhat makes a PDF large, and five ways to make it smaller without making it unreadable: compression, removing pages, splitting and re-exporting.
• How to redact a PDF properlyDrawing a black box over text doesn't remove it. Why common redaction methods leak, how to redact a PDF properly, and how to check the result.
• What is PDF/A?PDF/A explained: what makes it different from a normal PDF, the difference between PDF/A-1, 2 and 3 and levels a, b and u, and who requires it.
• PDF passwords explainedThe two kinds of PDF password, what print and copy restrictions really do, which encryption to use, and how to choose a password that holds.