Daylight affordance as ecological approach to domestic activities in House A in the ancient city of Orraon

Daylight affordance as an ecological factor that is inherent in the remains of built environments can contribute to our understanding of the locations and conditions of domestic activities within ancient dwellings. This paper discusses a general approach to assess daylight affordance and presents first results from the case study of Greek residential architecture in ancient Orraon. Orraon was founded in the Late Classical period at a key position for controlling the traffic and trade routes between central Epirus and the Ionian Sea. After its partial destruction by the Romans in 168 BC it was rebuilt and continued to be inhabited until the early Imperial period. Thanks to the use of a local limestone as the main building material, some of its residential dwellings, especially House A discussed here, have been preserved to such an extent that they allow the best possible reconstruction of their different construction phases, both in terms of building geometry and surface materiality. To calculate a metric for daylight affordance the method combines a digital reconstruction model with climate-based daylight simulation and a set of measurement geometries and thresholds for detail and colour vision in a spatial grid. This facilitates the study of domestic activities and their changes over the course of the house's history, which lasted around 300 years. The analysis of House A demonstrates clearly how activities demanding detailed or good colour vision are limited to certain rooms or areas within the building. It further suggests that architectural changes were driven by lighting conditions, too. These results can be read against the background of scholarly attributions of activities to certain rooms that are based on mere typological thoughts or the distribution of finds. It thus offers a new perspective on the methodologically difficult question of spatial use scenarios in ancient residential buildings. The method of applying the theoretical concept of daylight affordance to ancient architecture is still new. We are currently refining it on the basis of further case studies. Important insights are also expected from experimental archaeological approaches.