The term tagging has become synonymous with social websites such as youtube.com and flickr and with image sharing in general. By assigning "tags" or attributes – keywords, ratings, dates and captions to images – photographers can categorize and organize their content. With tagging, users can make an image collection more useful for sharing or personal viewing. Without tags, images can end up in a meaningless collection of files. But despite the growing use of tags, many new digital photographers do not understand them.
How tagging works
One of the most common tags is auto dating, the digital alternative to the ‘annoying’ timestamp printed on the front of many film-based pictures.
What many people do not realize is how that date is actually stored in a digital image, how best to change that value, and what other types of tags can be assigned after taking an image. Most images can save additional data elements within the image file.
A basic understanding of metadata is useful before tagging images. Metadata is information attached to an image, such as camera settings, time of exposure, date, etc. Tags are saved in metadata within the headers of each image. Headers are merely the portion of the image file that contains information other than the actual pixels of the image and are usually at the front (or head) of a file, which is where they get their name. Headers can contain different types of metadata such as EXIF, IPTC and XMP, but they all serve the same purpose of describing the image contained within that particular file. How to assign tags
The following example demonstrates how to assign tags within FotoAlbum Pro from FotoTime. In the following illustration, an image auto-dated by the camera on 4/25/2003 later was tagged with a caption, comment, keywords and a 3-star rating. Notice how the assigned tags were written into the appropriate metadata. This ensures maximum portability and longevity of the tagging operation.
The following reasons illustrate why it is important to ensure tags you add are saved into the images and how the metadata updating process can be performed without any image degradation.
Embedded tagging helps ensure that your tagging efforts can be ported to other applications or sites. The support for metadata tagging is growing and even if your favorite site or application may not be able to display or use a tag today, it most likely will in the future.
Metadata saved within each image is the only vendor-neutral method of ensuring tagging work is backed up when images are copied or backed up. Backing up the index data associated with particular programs is doable. However, users often overlook that data when performing data backups because the index data is in a location separate from the image files. If images are backed up with the metadata inside, you won’t lose your associated tags.
Metadata can be updated without any loss of image quality. Unlike modifying an image, metadata can be updated without having to decode and re-encode the picture (some applications support this). This ensures the image does not degrade every time tags are updated.
All cataloging programs, such as Adobe Photoshop Elements and FotoAlbum Pro, have their own characteristics with regard to importing and updating metadata. Whatever program you ultimately use, make sure it has the capability to update metadata with the tags you assign. FotoAlbum Pro can update metadata for date/time, captions, comments, keywords, author, copyright and ratings and display all metadata present in an image.
The key to an effective tagging strategy is to use an image organizer that understands the different metadata formats and, more importantly, can update the metadata whenever you make changes to the tags. While an increasing number of image organizers can import and display metadata tags, very few update the metadata and fewer still do it in “real-time” as you make changes. Benefits of Tagging
Taking a lot of photographs and placing them on a large hard drive is merely the collection phase. To truly enjoy large collections of images, tagging must be done so that images can be searched, sorted and grouped according to something other than picture date. Tags should be written into each file in order to ensure that the tagging effort is maintained as long as the files are preserved. Take full advantage of tags – tag often and tag smart!
Author: Andrew Pitts is the chief executive officer of FotoTime, one of the leading innovators in digital photo and video solutions designed to handle the entire digital image lifecycle.