"My oldest daughter, Lena was born on my birthday, September 9th, 1991. Every year on that day we make a birthday portrait of the two of us, assisted by my wife, Emily Matyas. This is an ongoing series. The making of birthday portraits is an ordinary family event and the pictures result from the natural desire to mark a moment in time, one year apart. Taken together this series carries personal significance for me as it also challenges my perception of life passing. The linear sequence suggests that growth and change and the direction of time, is one-way- confirming an ordered flow from past to present. But even though the duration between exposures is uniform, the rate of our change and our experience of time is not. We're both getting older, but for many years she was changing much faster than I was. Now, that relationship to change has begun to reverse itself and I am changing more rapidly than she. In a world where photographs represent individual moments, every moment of our lives can be made to exist side by side as ordered images. But the flow of experience, duration and rate of change is not necessarily uniform or in any one direction. I have often thought that change resulted from the passage of time. But I am starting to realize that the opposite is true: That change is the true measure of time passing." -Mark Klett