QUESTION: What is metadata?

ANSWER: Metadata is "data about data." Often, the term "metadata" is used to refer to data that helps to describe the content or characteristics of a file. For example, the metadata for a PDF file might include such things as

  • Title
  • Subject
  • Creator
  • Producer
  • Creation Date
  • Searchable keywords
  • Author and copyright information, status or notices
  • Special caption or headlines
  • Project name and description
  • File's project version number or final version notice
  • Owner URL, final posting URL or URL to a database containing more information relevant to a project.
  • Page Size

The metadata for a JPEG file includes such things as

  • Number of bits per sample
  • Number of lines in the image
  • Number of samples in each line in the image
This information is what enables software that displays or prints JPEG images to do those tasks properly.

Sometimes a document's metadata is embedded in the document file itself, whereas in other situations a document's metadata could be in a separate file.

Standards for metadata

There has been a movement toward adoption of a standard way of representing metadata and a standard way of embedding metadata into files. There are several standards relevant to the printing, publishing, and graphic-arts industries.

One such standard is referred to as XMP, which stands for eXtensible Metadata Platform. Adobe Systems Incorporated developed the XMP specification. Quite a few Adobe applications support XMP, including Adobe Acrobat, Adobe Illustrator, Adobe InDesign, Adobe Photoshop.

Opaque metadata

Metadata that is not organized in a standard format for which documentation is widely available is known as "opaque metadata."

Making use of metadata

Various software tools and systems are available that facilitate the task of utilizing metadata in various kinds of document files. Such software tools facilitate the tasks of creating, managing, and utilizing content by:

  • allowing for the creation of "smart assets" that retain context when passed across multiple file formats, software applications, devices, and databases
  • enabling flexible search and retrieval across diverse file formats and databases
  • facilitating workflow automation (content-management systems can be customized to automate tasks with the help of the metadata schema)
  • extending the content life cycle (files can be found and repurposed across multiple versions and renditions.

Software tools and systems that can make good use of XMP metadata are referred to as "XMP-enabled" software tools and systems.

See also What is XMP?