January 28, 2008
Exif, IPTC, XMP & The Mess We’re In
Adding proper support for Exif, IPTC & XMP data to the gallery application that powers my Eyeballism site proved a lot more tricky than could be considered healthy by any stretch of the imagination. We quickly found ourselves trying to decipher the image meta tag soup mess we’re in.
Some of the issues we encountered:
- data may or may not be present in Exif headers
- data may be present at different locations
- data may be present in different formats
- data may be present in different formats at different locations with different values
Terminology
For those among us who are new to image tagging, I’ll quickly explain some of the terminology used in this article.
- Exif: an outdated format mainly used for technical image data (aperture, date of capture, etc). This format has served us well up until this point, but it’s time for a replacement.
- IPTC: an outdated format used mainly for user description of the image (where was it taken? what keywords belong to the image? what copyright info?).
- XMP: a relatively new format developed by Adobe. This format could incorporate both Exif and IPTC data. XMP, being XML based, can be extended. For instance, unlike IPTC, it can deal with different character sets.
XMP & Industry Standards
I would really like to see speedy universal adoption of the XMP format. Standards are here for a reason: they generally make our lives more efficient, productive & enjoyable. XMP has the potential to become the imaging industry’s meta data standard. No more “Waiter, there’s a tag in my soup.“
It would be great if Apple would use XMP for tagging in their Aperture suite. As far as I know Adobe has released the XMP toolkit under a standard BSD license, so it allows other manufacturers to integrate it into their own proprietary applications.
Camera manufacturers for some time now have been adding their own “standards.” Enough already with the “Exif MakerFiles.” This is confusing and counter-productive for independent software developers. I venture to suggest it will be equally confusing for the developers employed by the camera manufacturers: “Which standards are we working with today boss?“
The Added Value Of Meta Data
In a time where meta data is becoming increasingly important, we really should pull together and set up & follow industry standards.
For instance, over 3,000 images were added to Flickr in the time it took me to write this sentence. Suppose that a mere 1 percent of these images were properly tagged (keywords/location/etc). That still equates to around 45,000 tagged images per day. This number is likely to increase when people become more aware of the benefits of tagging content and geo-tagging is more widely adopted (wireless meta data transfer between your camera and GPS enabled mobile phone?).
Tagged content has added value for its consumers and ensures it can be found in the first place. Tags could very well be the single most important reason behind the success of Flickr and YouTube. Enough said.