As a genealogist, you may find yourself with a collection of old photographs and the fortunate few, will have names, dates and sometimes even places hand lettered on the front or back. One advantage of digital photos is that data about the photographs, the subject matter, the identity of the individuals and the place can be digitally included with the original and any copies. A considerable amount of data is automatically attached to digital photos by the camera and that more can be added, including geolocation information.
Some authorities try to make a distinction between the terms "data" and "information." In our technical computer world, information is usually considered to be the raw unorganized stream of anything. Once the information is organized in a form that can be recognized by a computer, it becomes data. Using this definition, the outside world containing a birthday party is the information. When you point a camera at the party and push the shutter button, you select a portion of the overall information in the scene that is then transformed by the camera into data or in other words, a photograph. Realistically, both terms are often used interchangeably, but in order to discuss metadata, I have to make a distinction between information and data.
Metadata is data about data. When you take a picture with a digital camera, the light sensor almost instantly gathers in information in the form of a photographic image. If you then consider a photograph to be a "data set" or collection of information, additional attached information about the photograph itself; the camera used, the settings, the date and time, the location and many other types of information comprise the metadata. The additional data (metadata) adds to and gives meaning to the original data. The metadata is not usually readily ascertainable from the original photograph. For example, by looking at the photogrpah you cannot easily tell what kind of camera was used to produce the picture. Using my first reference above, writing on the back of an old photograph could be considered as metadata.
A paper photograph has already lost all of the associated metadata which could have been included. Unless the photographer was a meticulous professional, it is highly unlikely that very much of the surrounding information about the photo was preserved. Part of the detective work of genealogists is trying to puzzle out the metadata of old photographs to give them meaning and context and even just to identify the people. Unfortunately, many, probably almost all, present day digital photographers fail to take advantage of the metadata opportunities afforded by their choice of digital imagery.
As I already mentioned, all digital cameras automatically store information about the camera and its settings with each picture. The problem is that this information is mostly hidden, either in attached files or embedded in the photographic file itself. Many of the current photo manipulation, storage and editing programs have a way to display some or all of this hidden metadata after the photo is downloaded to your computer. For example, iPhoto from Apple will show some information including the camera manufacturer, model, size of the photo, the original date, the digitized date, modification date and date the picture was imported. Another program, Picassa from Google, can show the dimensions of the photo, the camera make, the camera model, the camera date, the resolution, the orientation, whether a flash was used or not, the focal length of the lens, the 35mm equivalent, the CCD width, the exposure time, the aperture, the ISO, the exposure bias, the metering mode, the color profile name, the size of the thumbnail view, the quality of the JPEG image and the photo's unique ID. Don't worry if you don't have a clue as to what all this stuff means. Unfortunately, nearly all of that information is useful only to a photographer not to genealogist. With Picassa you can also add tags which are essentially metadata and the tags can contain geographic information.
Some makes of cameras and some cameras in cell phones have GPS (Global Positioning System) capabilities and mark the location of every picture taken. This is only helpful if you have a way of viewing the attached metadata. One program that gives you virtually unlimited ability to add metadata, including geolocation information is Adobe Bridge. Bridge is sold as a companion program with either Adobe Photoshop Essentials or the full Photoshop program. There are several other programs, some shareware, that will also add the metadata.
Tune in for the next installment on the advantage of metadata.