Façades versus Public Displays

Media façades are a prominent example of the digital augmentation of urban spaces. They denote the concept of turning the surface of a building into a large-scale urban screen. Due to their enormous size, they require interaction at a distance and they have a high level of visibility. Additionally, they are situated in a highly dynamic urban environment with rapidly changing conditions, which results in settings that are neither comparable, nor reproducible. Altogether, this makes the development of interactive media façade installations a challenging task. Over the last years, urban environments and public places emerged as prime locations for deploying digital technologies, which increasingly affect the daily life [16]. For example, they optimize heating systems in buildings, balance the flow of electricity through the power grid, and keep autonomous public transportation networks moving [16]. Hence, urban environments are on their way of being turned into dynamic and programmable surfaces [11]. The notion of Smart Cities increasingly enjoyed popularity over the last decade. There are enormous efforts by the European Union, governments and cities to make them smart in different domains by utilizing information technologies (IT). Some parts of this technology are visible, for example when long serving artifacts such as analog billboards for advertising are being replaced by digital displays. The computer chip manufacturer Intel estimated in a recent case study on digital signage that the number of digital public displays will reach 22 millions screens worldwide by the year 2015. As a consequence one of the main goals when planning and building urban environments is to achieve that the residents identify with it [14]. Architectural principles state that an effective way of achieving identification is to focus in the design process on the communication between people and buildings [17]. Besides large scale digital displays, an increasing number of media façades are embedded into the urban landscape (compare Figure 1), becoming more and more ubiquitous. In a common sense, the term media façade describes the idea of turning the façade of a building into a very large public screen by equipping its outer shell with interactive, light-emitting elements [12,14]. However, untill now, there is no clear definition that sufficiently delimits media façades from urban media architecture and large-scale digital displays, which are embedded into the urban environment. In this case the display appears as a second skin of the building. Media façades can be classified based on different characteristics and properties. Among others, these might include their technical composition, as well as the main principles of how content can be displayed. Along with media façades, the manifold use of light and light-emitting elements in general plays a more and more important role in the architecture of urban environments. In this sense, we have to note the differences between lighting architecture, media architecture and media façades. Haeusler [12] distinguishes these terms as follows: Lighting architecture subsumes the illumination of a building using daylight and artificial light in order to underline parts of the building to create a certain atmosphere. This also holds for media architecture, whereas media architecture also includes all aspects of dynamically displaying media, such as dynamic graphics, dynamic text and spatial movement, but with a strong focus on dynamic content. Media façades build on this by including media to transform the building façade into a communicative element.The transition between lighting architecture, media architecture and media façades can be seamless. While media façades enable communication via technologies onto a façade in the form of digital media, and media architecture describes the cultural, social and economic implications of these façades for the immediate