For the word 'Luminous' (my daughter's idea) and for the angel wings (my son's idea), I set the exposure for fifteen seconds. Also, writing words is harder than it looks as she had to write backwards! We worked that out pretty quickly :) I also used the Bulb option on my camera which until very recently I had successfully ignored because I hadn't bothered to find out what its purpose is! It basically means that you can carry on taking a photograph for longer than the thirty seconds maximum that most DSLR's allow. The preview screen on my Canon is also a touch screen which made this easier. I turned the dial to Bulb, pressed the screen when I was ready to start and pressed it again to finish. Simple but the effects are incredible. It's also very important to use a tripod when attempting photographs like these. There is no way anyone can hold a camera perfectly still least of all me. My tripod has since come out of hiding and I am not sure how I managed without it. It's always there just waiting...