Ravenna Master Mosaicists
425–565Byzantine-Italian · Byzantine Mosaic Art 330–1453
The mosaicists of Ravenna set glass cubes at deliberately irregular angles so that candlelight would never strike them evenly. The shimmer is not a happy accident; it is engineered.
Formation
Ravenna became the capital of the Western Roman Empire in 402, then of Ostrogothic Italy, then the seat of Byzantine power in the West after Justinian's reconquest in 540 — three regimes in a century and a half, each of which built and decorated. The workshops were almost certainly mixed, with craftsmen trained in the eastern Mediterranean working alongside local labour, and the individual names are unrecorded. The mosaics of San Vitale, Sant'Apollinare and the Mausoleum of Galla Placidia were made across roughly a hundred and forty years.
Technique
Tesserae of coloured glass, stone and gold leaf sandwiched between glass, pressed into wet lime plaster over a prepared wall. The technical sophistication lies in the setting: cubes are tilted at varying angles rather than laid flat, so that a curved surface catches light from many directions at once and the image appears to move as the viewer walks past or as a candle flickers. Gold tesserae are set at a slightly steeper angle than the surrounding colour. Joints are left wide and irregular, and the mortar between them functions as a dark drawing line.
The palette
Gold above all, as a ground rather than a colour — a gold background is not a place but an absence of place, an uncreated light. Against it: deep blues from cobalt-coloured glass, greens, the purple reserved for imperial figures, white marble for highlights, and terracotta and stone for flesh. Colour is applied in flat zones with abrupt transitions, since a tessera cannot be blended, and the modelling of a face is achieved with three or four discrete tones set side by side.
Legacy
These are the best-preserved Byzantine mosaics anywhere, better than most of what survives in Constantinople itself, and they are the reference point for the entire tradition. Klimt visited Ravenna in 1903, and the Golden Phase follows immediately — one of the most traceable single influences in this atlas. The gold ground persists in Italian panel painting for eight hundred years afterward.
Palette
The colours reconstructed for this artist, with the reasoning behind each.
Pigments used: Gold leaf · Cobalt blue