Fresco in the sun
The dials are designed as frescoes (pigment diluted in water and applied on a still fresh airborne lime coating and marble powder). The fresco offers numerous advantages over other techniques of painting on the exterior of a building: as a mineral material, the fresco reacts to light and hygrometric variations such as the white cast concrete of the facade or the larch wood of the panelling. In some of my early project, and when storing some historical dials, I observed that pigments mixed with the fresco withstand attack by UV radiation more effectively than any other paint. This type of coating “breaths” and is chemically compatible with all internal supports, thereby facilitating its adhesion
The fresco coating is very fine (about 5 mm thick) and is clearly demarcated at the circle of the dials. When the surface of the motif is too large to be painted in a day, the application of the coating is divided according to the outlines of the parts to be pained. Each “day” is connected to the previous days, like fish scales.

I will not dwell on the technical considerations of the fresco which induces me to be lyrical despite the physical commitment that it requires. The balance between the preparation of the coating, its execution, the transformation of the colours when drying and the various tonalities varying according to the light makes this a unique technique half way between masonry and painting. These gestures have hardly changed in three millennia. It is hard for me to contemplate sundials on buildings without using the fresco.