IPTC and keywords

As well as picture data, image files contain extra information known as metadata which tells you about the photo – metadata literally means ‘data about data’.

Some of this metadata is recorded at the time the photo is shot and includes details of the camera make, model and serial number, the exposure settings, the time and date, whether the flash fired and even which way up the camera was held.

This camera data is in a standard format called Exif (Exchangeable Image File Format).

Another acronym that you’ll see applied to image metadata is IPTC (International Press Telecommunications Council). This applies to data added after the photo was taken, including a title, description, copyright notice and keywords.

The IPTC standard originated with the need for information in a standard format to accompany press pictures. It includes many other fields providing additional information about the image content as well as the photographer, but photo album software, if it supports IPTC at all, tends to include only the title, description and keyword fields.

Photo album applications are simply databases for images. In order to be able to quickly locate and display individual photos, or groups of photos from among thousands, they store information about your pictures in a text-only database.

The advantage of using a database is speed, the disadvantage is that your photo files and the information about them are stored in two separate locations, some of it is in the photos themselves, the rest is in the album application’s database.

For Exif data this isn’t really an issue because you don’t usually change it and it remains embedded in the original photo file.

With IPTC data, if you mean to use it as intended (to provide information about your photos to others) you must ensure your album application can write the data from the database back into the photo file.

The issue is more critical (and confusing) when it comes to keywords. Typically these will exist independently in two locations – the IPTC keywords field in the photo file and the album application’s database.

This isn’t necessarily a problem – some applications just ignore the IPTC keywords, others support them and allow you to append database keywords to the IPTC keywords. However, Corel Photo Album 6 overwrote the existing IPTC keywords in our tests with new keywords.

As well as being aware of the difference between database and image file data, for obvious reasons you must also ensure your album database is regularly backed up.

This article is part of a group test of photo album software
See also
ACDSee 8 Photo Manager
Adobe Photoshop Elements 4.0
Corel Photo Album 6
Google Picasa 2
Microsoft Digital Image Suite 2006
Serif Album Plus 4

The table of features can be read via our pdf downloads above