Some years ago I was rummaging through some photographs taken by my father, when it occured to me that the significance of a photograph can change over time. A photograph that can be considered to be just a snap now can convey so much more information, simply through the passage of time. I'm sure everyone has informal family portraits that captured ephemeral moments but the photographs later became much more significant with the loss of a loved one. Even simple things such as capturing the use of some outdated technology or clothes that have long since become unfashionable may be enough.