Unusual Rainbow. Images and Projections Between Art and Science

What do have in common a friar lived in the XVII century, a contemporary American artist belonging to the land art movement and an Italian structural engineer become famous between the two world wars? The answer can be certainly found in the common scientific approach of the three authors, but more precisely in their shared passion for the natural phenomenon of rainbow. The paper focus on the contextualization of studies relating to this atmospheric phenomenon - investigated since the classical period - considering its depictions in the history of science and art. Among the protagonists of this story, whose approaches are between aesthetic researches and natural philosophy, we find the friar Emmanuel Maignan (1601–1676), a scholar of optics and author of one of the most important gnomonic treatises of the Baroque period. From 1980 the artist Charles Ross had used big glass prisms, precisely oriented, to project the chromatic spectrum inside architectural scale installations. Finally the engineer Arturo Danusso (1880–1968) developed in the early decades of the 1900s a method for evaluating the tension stress of reinforced concrete structures based on photoelasticity. Beyond the examination of the heterogeneous uses of rainbow in art and science, the paper also intends to focus on the relation between light and optics assumed as an ‘universal method’ for investigating natural phenomena during the centuries.