Not all PDFs are equal. Different formats serve different purposes — sending the wrong one to a printer can ruin your output. Here is a plain-English breakdown.
The everyday PDF you create when you hit "Save as PDF" in Word or Chrome. Supports text, images, links, and basic forms. Best for screen viewing, email attachments, and general sharing.
Designed for long-term preservation. PDF/A embeds all fonts inside the file, prohibits external content (like linked images), and bans JavaScript and encryption. Governments, libraries, and legal systems require PDF/A for official records. Sub-types: PDF/A-1 (basic), PDF/A-2 (supports layers and JPEG2000), PDF/A-3 (allows embedded attachments).
Built for professional printing. PDF/X requires all fonts to be embedded, all images to be CMYK, and all color profiles to be specified. Print shops ask for PDF/X because it eliminates ambiguity — what you see on screen is what comes off the press. Common versions: PDF/X-1a (CMYK only), PDF/X-4 (allows RGB with color management).
Optimised for CAD and technical drawings. Supports 3D models, layers, and large-format pages (A0, A1). Used in architecture, manufacturing, and construction.
Ensures PDFs are readable by screen readers and assistive technologies. Requires tagged content, alt text for images, and logical reading order. Mandatory for government websites under WCAG 2.1 guidelines.
| Use Case | Recommended Format |
|---|---|
| Email attachment | Standard PDF |
| Legal archive | PDF/A-2 |
| Commercial print | PDF/X-4 |
| Public website | PDF/UA |