Temporary Nocturnal Signs: to draw with lighting and luminous materials for the urban regeneration

The night-time of the city can be designed with the aim of increasing the perceptive quality of space in terms of comfort and safety, through a good lighting project. The strategic use of artificial light and luminous materials reinterpreted as nocturnal messages helps to convey information and define an image of the city other than the daytime. The light helps to expand the city life at night by creating new points of interest, provoking discussions and attracting an increasing number of people. This also helps to reduce criminal acts. Analogue, digital or virtual graffiti that use the medium of light, allow to modify the nocturnal city, illuminating it and using light as a sign on a black canvas. Drawing with light on urban surfaces is also a way in which urban artists can express their creativity in a more responsible and sustainable way, to regenerate the urban landscape. In this article, we propose an analysis of case studies that results in a taxonomy aimed at investigating the following characteristics: temporal and spatial localization, intent of installations, graphic and communicative level, and symbolic and semiotic content. The aim is to outline a first descriptive framework, identifying how these phenomena affect the city and society, the designer and the design process. Many lighting techniques and technologies are becoming important to communicate with the public the importance of lighting in regenerating the city at night and are also at the service of designers as tools to stage their ideas quickly and in a visually effective way.