Think that you know the ancient Greek statues? Think again. These marble marvels were once brightly painted, but thousands of years of wear have stripped these masterpieces of their true hue. But modern technology can now detect patterns and colors that were once thought to be lost.
According to io9: "A technique called ‘raking light' has been used to analyze art for a long time. A lamp is positioned carefully enough that the path of the light is almost parallel to the surface of the object. When used on paintings, this makes brushstrokes, grit, and dust obvious. On statues, the effect is more subtle. Brush-strokes are impossible to see, but because different paints wear off at different rates, the stone is raised in some places – protected from erosion by its cap of paint – and lowered in others. Elaborate patterns become visible.
Ultraviolet is also used to discern patterns. UV light makes many organic compounds fluoresce. Art dealers use UV lights to check if art has been touched up, since older paints have a lot of organic compounds and modern paints have relatively little. On ancient Greek statues, tiny fragments of pigment still left on the surface glow bright, illuminating more detailed patterns.
Infrared and X-ray spectroscopy can help researchers understand what the paints are made of, and how they looked all that time ago."