Colors and daylight in Pompeii: how light affects colors and colors affect light

Pompeii offers amazing examples about the use of daylight by ancient roman architecture and substantially they can be interpreted and analyzed by two different points of view: on one side it’s possible to evaluate how, by means of on field measures and simulation techniques, during the ancient life of Pompeii both the architecture and the choice of colors controlled daylight spatial and spectral distribution and created environmental effects; on the other it’s important to assess how daylight is used at today, in spaces that often can be defined “neither indoor nor outdoor”, given the modifications occurred during the modern life of this archeological site. In the latter case it’s fundamental to analyze lighting conditions along the visit paths, in order to avoid that critical effects as glare phenomena or excessive luminance contrasts could impair the correct perception of spaces and artworks. From the results obtained by a measurement campaign, including wall color paintings’ spectral reflectance and spectral characteristics of light, a deep interconnection between light and colors has been revealed: not only light, with its variation during daytime affects colors appearance, but colors used for wall paintings, together with architectural characteristics, affect the color of light, creating warm or cool atmospheres.