The Play of Light

The sixth century apse mosaic at Sinai depicts the Transfiguration of Christ. His garments are white, with shades of light grey. They are bordered by gold bands, executed in tesserae of light gold, dark gold, and tesserae with gold leaf.

When the light is direct, the gold leaf is bright, and it blends with the light gold tesserae. When the light is oblique, the gold leaf is dark, and it then blends with the dark gold tesserae. This play of light was clearly understood by the artists who created the mosaic so many centuries ago.