IPTC, Exim and other Meta-Data for Photos
When you have a huge collection of photos, chances are you’ll have a hard time sorting them by category, copyright and others. Photo editing software such as Photoshop supports adding metadata in a file. The following are the most common format used for metadata tagging.
IPTC Format
This format was defined by the International Press Telecommunications Council. In 1994, Adobe defined a specification that would allow adding IPTC headers in JPEG, TIFF and PSD file. The most format are: Instructions, Keywords, Photogapher, Copyright, Credit, City, State, Country, Date.
Extensible Metadata Platform (XMP)
This format is used for photography, PDF and photo editing application. First introduced by Adobe System in 2001 to define the schemes for attributes for recording changes on a file. XMP format can be used for JPEG, JPEG 2000, GIF, PNG, HTML, TIFF, Illustrator file, PSD, PostScript and Encapsulated Postscript.
Exchangeable Image File Format (EXIF)
EXIF metadata for image file are commonly used by digital cameras to preserving the important attributes of an image such as: manufacturer and model of the camera, orientation, software version, date/time (original, digitized) , comression (JPEG), resolution (x and y), unit of resolution, Exif version, exposure, flash (on or off),maximum aperture value, color space( sRGB ). Exif specification also describes the RIFF file format for WAV audio files.
For developers, these metadata are of big help when importing large quantities of images to your main data store. A couple of libraries that you can use to get most of the benefit of these meta data are the following:
For PHP
- iptcparse Image Function
- PEAR Image_IPTC
- The PHP JPEG Metadata Toolkit (free, GPL)
- PHP EXIF function
For Java
For Python
For regular users who just love to collect and share photos, most photo sharing sites and softwares nowadays fully supports these popular metadata format. Any unmodified images (even those modified by image program that supports metadata inclusion) can be directly uploaded to your favorite photo sharing site and it will properly categorized and tagged.