The city at night is a marvellous place. The way you experience its buildings and urban space is so different from the experience you have during daytime, that with sunset a completely different city arises. Light is the defining feature during this time. You can change its quantity, but also its qualities: intensity, rhythm, size, form, temperature and finally colour. A conscious project, which takes light’s physical qualities into account, recent technological developments as well as its experiential effects, could create a relation between different forms of light and specific nocturnal urban spaces. This way light could be used to strengthen the identity of a place, because a park is lit in a specific colour. It could help someone to find his way through the night, because certain main streets could have a different colour, based on the frequency of taxis passing. It could help to communicate to the citizen upcoming events such as the extend of a future urban intervention inside the city.