# Preserve PDF Metadata and Properties When Merging
A colleague once merged 50 client contracts into one master document. Everything looked perfect—all pages were there, in the correct order, properly formatted.
But then legal complained: all the original author information, creation dates, and document tracking metadata had vanished. For compliance auditing, that metadata was critical. The merge had essentially erased the document's history.
This is a hidden problem with PDF merging. Most tools focus on combining visual content—the pages you see—but completely ignore or strip out the invisible metadata that often matters just as much.
In this guide, I'll show you exactly how to preserve PDF metadata and properties when merging. We'll cover what metadata exists in PDFs, why it matters, and how to maintain (or selectively merge) it using various tools and techniques.
Understanding PDF Metadata
PDF metadata is information about the document that isn't part of the visible content. Think of it as the document's "identity card."
Standard Metadata Fields
Every PDF can contain these common properties:
Title - The document's title (not necessarily the filename)
Author - Who created the document
Subject - Brief description of the document's content
Keywords - Search terms associated with the document
Creator - The application that created the original document (e.g., "Microsoft Word")
Producer - The software that created the PDF (e.g., "Adobe PDF Library")
Creation Date - When the original document was created
Modification Date - When it was last modified
Trapped - Whether the document is prepress-trapped
Custom Metadata (XMP)
PDFs can also store custom metadata in XMP (Extensible Metadata Platform) format:
- Copyright information
- License terms
- Document ID and version
- Custom business fields (case numbers, client IDs, etc.)
- Rights management info
- Geolocation data