There’s room for more than meets the eye inside a digital photo image file. Regardless of the format, these files can store not only image data but also information about the images. Metadata is, literally, data about data. When included in image files, we call this information “photo metadata.”  Metadata is actually part of the image file, effectively a bundle of image data and information about that image.

Digital photo files can include descriptive, technical (sometimes called structural) and administrative classes of metadata of several types. These can list an image’s creator, copyright holder, source and description. They can explain rights released and available to an image. They can list how and when an image was created, its size, color characteristics and more. Read our Metadata FAQs

Embedding and preserving photo metadata can prevent and solve many issues confronting photographers and others who work with digital images. Our goal is to help everyone involved with digital photos – from image creators to distributors, users, archivists and developers – better understand photo metadata and best practices for harnessing this amazing tool to organize and communicate. Read our Metadata Manifesto

Are you ready to get meta-smart?

Start by reading our Metadata Manifesto.It explains the challenges we face in protecting
identifying, and managing or digital photos.

Ready to dig a little deeper? Tackle our list of Recommended Reading.

View our View META Tutorials which include screencast tutorials and step-by-step instructions showing you how to embed metadata using a range of popular software tools.

SAA's Manifesto put forth three guiding principles:

Metadata is essential to identify and track digital images.

Ownership metadata must never be removed.

Metadata must be written in formats that are understood by all.

Now, we need to take these guiding principles and put them into practice.

This starts with industry wide commitment to use metadata. We then need to embrace metadata standards and best practices that have a consistent world-view approach. Finally, we need technology that makes it easy to embed metadata, preserve it, and facilitate tracking and rights management.

SAA’s “Manifesto” concludes with a list of specific action steps for photographers, distributors and end users, and offers guidance for developers.

Read the Manifesto

MetaSurvey of Stock Distributors
The first phase centered on a comprehensive survey of metadata practices among major stock image distributors. The study looked at a representative group which included Getty Images, Corbis, Jupiterimages, Masterfile and Alamy.  SAA conducted extensive random sampling of digital image files available on their websites to document the presence of metadata in both "thumbnails" and larger "preview" images. The team then tracked sample images to see what happens to embedded metadata as files are forwarded on from distributors to multiple sub-distributors.

Preliminary findings confirmed what SAA has long suspected: Too many images in the licensing market lack key identifying and content information.

After presenting our preliminary findings at major industry conferences including the 2008 Microsoft Pro Photo Summit and 2008 International Photo Metadata Conference, and sharing them with stock distributors and fellow association leadership, the SAA Photo Metadata Project team gained a better understanding of the challenges that need to be met to implement best practices across the licensing industry.

A white paper report of MetaSurvey findings is currently in development.

MetaSurvey of Photographers
With the launch of the Project web site, the second phase of our MetaSurvey begins with an online questionnaire directed to pro photographers of all types. We hope to gain broad participation in the survey which will give us a better idea of the level of metadata use in the pro photo comunity, including types of metadata embedded, software tools used, and insights into digital imaging workflows.

Photographers, Take the MetaSurvey!

Later in 2009, a report of our findings will be posted to this site.

Some classes of metadata can be - and are - embedded in digital image files. Some schemas, or data formats, actually identify their elements by these classes, although this may not be readily apparent. Each of the followig three “classes” of metadata become part of the image file when embedded in JPEG, TIFF, PSD, Raw or several other popular formats. They can also be stored in a sidecar file.

Technical Metadata
Most modern image-capture devices generate information about themselves and the pictures they record, such as that stored in Exif. These data describe an image’s technical characteristics, such as its size, color profile, ISO speed and other camera settings. Some professional cameras can be configured to add detailed ownership and descriptive information in a note or comment field stored within the Exif container.

Descriptive Metadata
A photographer or image collection manager can enter and embed various information about an image’s contents. This can include captions, headlines, titles, keywords, location of capture, etc. These metadata fields were included in the original IPTC-IIM schema. They have been expanded in the IPTC Core and IPTC Extension metadata schemas. Good descriptive metadata are key to unlocking an image collection to find stored images.

Administrative Metadata
Image files can also include licensing or rights usage terms, specific restrictions on using an image, model releases, provenance information, such as the identity of the creator, and contact information for the rights holder or licensor. These types of metadata have been comprehensively addressed and standardized within the PLUS sytem. The IPTC Core and IPTC Extension schemas also expand on the types and quantity of such information metadata can store.

Named for Dublin, Ohio, where a gathering of librarians first discussed its need, the schema is now maintained by the Dublin Core Metadata Initiative (DCMI). DC comprises 15 basic elements. The NISO (National Information Standards Organization) and ISO (International Standards Organization) have accepted it as a standard. The current IPTC Core schema has five fields interoperable with Dublin Core (Title, Subject/Keywords, Creator, Rights/Copyright Notice, Description).

Official Dublin Core Website: http://dublincore.org/

Digital cameras embed technical metadata, called Exif data, into image files (primarily JPEG and TIFF formats) they create.

Exif’s primary feature is its ability to record camera information in an image file at the point of capture. Some common data fields include the camera make and model, its serial number, the date and time of image capture, the shutter speed, the aperture, the lens used and the ISO speed setting. Exif metadata often includes other technical details, such as white balance and distance to the subject.

Exif metadata can also include thumbnails along with technical and primary image data in a single image file.

The Exif standard was established in 1985 by the JCIA (Japan Camera Industry Association), the predecessor of CIPA (Camera & Imaging Products Association). Today, JEITA  (Japan Electronics and Information Technology Industries Association) manages the standard, while CIPA discusses new technology and promotes the standard.

Although Exif data come primarily from digital cameras, some scanner drivers also write such information in the files they generate. Raw file processing software can use the Exif information to more accurately render the images, and new technologies, such as Exif 2.2 (also called “Exif Print”), incorporate this photographic information to help render a photographers' intentions in finished prints.

A fairly comprehensive list of the various attributes which can be stored in Exif (Exif Tags) can be found on Phil Harvey's ExifTool site.

History of the Exif standard

Source: Hiroshi Maeno, Canon Inc. June, 7, 2007, First International Photo Metadata Conference, Florence, Italy.

Official JEITA Website: http://www.jeita.or.jp/

Exif Print PDF on CIPA site: http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf

Unofficial Exif Website: http://www.exif.org/

The Extensible Metadata Platform or XMP is a specific type of extensible markup language used to store metadata in digital photos. Adobe introduced the format in 2001 when it released Photoshop 7.

Adobe, IPTC and IDEAlliance then collaborated in 2004 to introduce the IPTC Core Schema for XMP. It transfers metadata values from IPTC headers to the more modern and flexible XMP format.

A unique advantage of XMP is that it allows creation of custom metadata panels. These not only store additional forms of data, but also organize it differently from Photoshop’s "File Info" defaults. These XMP-based panels can be installed in Photoshop (see http://www.adobe.com/products/xmp/custompanel.html for details), and allow anyone to insert custom metadata in image files.

Understand, however, that while you can add custom information this way, only Adobe Photoshop and Bridge, along with a few other image databases can import or see these metadata. And custom panels require additional set up work before others can use them.

Deeper Reading:

XMP is a combination of XML and RDF. XML is like HTML. But while HTML focuses on the presentation of data, XML is concerned with “representation.” Additionally, XML is non-proprietary, operating system independent, fairly simple to interpret, text-based and cheap. RDF is the WC3's solution to integrate a variety of different applications using XML as an interchange syntax. Some uses include library catalogs, worldwide directories, news feeds and software, as well as as collections of music, images and events.

Together, the specifications provide a method that uses a lightweight ontology based on the Dublin Core. It also supports the “Semantic Web” (allowing for easy exchange of knowledge on the Web).

A good comparison for how the Dublin Core metadata fields compare to the IPTC fields was on a Dartmouth University site: http://www.dartmouth.edu/comp/about/projects/digitalmedia/images/resources/metadata-schemas.html (now linking to the page on the Internet Archive Wayback Machine).

A recently introduced form of photo metadata, the Picture Licensing Universal System, provides an integrated set of standards for communicating rights and ownership information associated with commissioned and existing images.

The international, non-profit PLUS Coalition develops, approves and maintains a set of standards for licensing language and formats. It serves as an umbrella association representing publishers, designers, advertising agencies, photographers, illustrators, stock image distributors, artist representatives, museums, libraries and standards bodies, such as UPDIG, IPTC, IDEAlliance and others.

The PLUS website offers free tools to embed and read PLUS licenses using an XMP metadata format. A license string can reside in IPTC or XMP metadata, with potential for direct embedding in an image file.

PLUS metadata help with Orphan Works impacts.
The ability to easily identify and contact an image’s rights owner will become vitally important when proposed “Orphan Works” legislation or copyright reform acts become law. Regardless of where first enacted, such changes would affect photographers worldwide. If the bills proposed recently in the United States passed, they would allow anyone in possession of an image to use it for virtually any purpose (including commercial use), after conducting a reasonably diligent search and failing to locate the copyright owner. Under this broad definition, any and all images previously circulated without rights metadata could be defined as “orphaned” images. Embedding complete and accurate rights metadata using IPTC, IPTC Core and/or PLUS metadata helps protect images from these and other unlicensed uses. Several countries are considering similar legislation, and Canada already has a copyright board that makes decisions on works produced by “unlocatable” copyright owners.

Official PLUS Website: http://www.useplus.org

SAA's Calculator brings PLUS Packs™ to life.
To help spur adoption of the standard, SAA developed the SAA PLUS Packs™Calculator. Based on the licensor's own pricing data, this free, open-source software tool automates the first step of the licensing process - selection and pricing of a Pack. On one screen, and with just a few clicks, RM (Rights Managed) licensing will be easier than ever. Learn more about SAA's Calculator

In 2005, the International Press and Telecommunications Council released an updated standard for using IPTC data within Adobe's XMP schema, dubbed the “IPTC Core.” This enables IPTC data to be incorporated (via XMP) into a wider range of image formats, such as JPEG, TIFF, JPEG2000, DNG and more.

Since XMP supports Unicode text, it can represent non-Roman alphabets (such as Cyrillic, Japanese, Chinese). It also solves the issue of diacritical characters getting garbled when moving images between Macintosh and Windows operating systems. Unlike the legacy format, IPTC Core does not have specific character limits for each field, except for maintaining backward compatibility with the original IPTC schema.

This format, initially named IPTC4XMP, after its working group’s moniker, stores information separately from the IIM form of IPTC metadata. But it shares many fields, and they are largely backward compatible. The IPTC Core Schema for XMP comprises the fields included in the IPTC Contact, Image, Content and Status panels that appear within the File>File Info menu item in Adobe Photoshop.

When you first open the File Info panel in recent versions of Photoshop, you see the built-in Description panel. The IPTC Core Custom Panels appear along the left-hand side (Photoshop CS through CS3), or along the top (Photoshop CS4) as one of several choices.

IPTC Official Website: http://www.iptc.org/

IPTC Core (IPTC Metadata for XMP): http://www.iptc.org/IPTC4XMP/

While now considered a legacy format, the International Press and Telecommunications Council’s original schema is widely recognized by software products that access metadata, many of which cannot read or write the more recently defined IPTC Core/XMP schema.

Based on a format for text files that described accompanying media, the IPTC’s Information Interchange Model (or IIM for short) launched in 1991, providing a new way to handle “digital resources” with metadata and content held in a binary-structured framework. In the mid-1990s, Adobe added the ability to insert descriptive metadata in TIFF and JPEG digital image files, giving birth to IPTC headers. An Adobe-specific container or “wrapper,” dubbed the Image Resource Block (IRB), encapsulated a subset of the IPTC’s IIM metadata structure, allowing editing through the Photoshop "File Info" dialog.

The IIM as introduced was designed for describing all types of media (articles, images, etc). Some of the early digital imaging programs (like Photoshop) found it to be particularly useful set of values, and a subset of them were adopted by the photographer community. After the release of the IPTC Core in 2005, it was no longer the only method of embedding photo metadata, and the tide has been slowly turning. Many of the better applications embraced the XMP method of storing metadata, but maintain backwards compatibility with the IIM standard by synchronizing the data and writing the saved values (for any shared fields) into both the IIM and XMP containers.

Many third-party developers have created software applications that read and write to IPTC headers. But some consider it metadata “black art,” since the storage location and structure vary with image file formats. Occasional glitches appear in how certain diacritical characters - such as accents, tildes, umlauts, etc. (áçèîñõü) - translate when exchanging files between operating systems. This schema also has specific limits on the number of characters each field can hold.

For specifics on the various field names used in different imaging applications, you might want to download the IPTC Core mapping chart on the Controlled Vocabulary website
 

IPTC Official Website: http://www.iptc.org/