THE ANCIENT MOSAICS
Aut lux hic nata est
aut capta hic libera regnat
(Light was either born
or captured here, and here reigneth freely)
In order to decorate the walls and the domes of the early Christian or Byzantine basilicas mosaicists used “tesserae” made of glass which, in comparison to stone and marble, have the the advantage to be lighter and brighter. The colour is obtained by adding metal oxides to ordinary glass during fusion.
According to the type of oxides used we will obtain a different range of coloured tesserae, i.e. cobalt oxide for blue, copper oxide for green and red and manganese oxide for purple.
For golden and silver tesserae another procedure is adopted. In fact for these kinds of tesserae the colour is not obtained by using any particular oxides but by sandwiching a very thin metal leaf (of gold or silver) between two layers of transparent glass: one slightly thicker acting as a base, the other used as a protective glass film, commonly called “cartellina”. This is the reason why these tesserae are more precious than the others.
If compared to painting, mosaic art offers the advantage of inalterability of colour and resistance: therefore it is suitable for decorations on surfaces exposed to atmospheric agents as well as for decorations on hard surfaces like floors.
Mosaic art is durable, it is not subjected to corrosion or atmospheric alterations, it always preserves its fresh lively brilliant splendour. For this reason a famous italian artist of the XV century considered it “la vera pittura per l’eternità” that is to say a real eternal painting.
MOSAIC ART TODAY