• The so-called "Cuirass-Torso," discovered on the Acropolis in Athens in 1896, would have been carved about 470 B.C. At first glance, the piece looks like a typical classical nude. In the 1990s, however, close study of the marble's surface revealed traces of an elaborately decorated undertunic that had once been painted poking out from all around the figure's torso. In ancient times, that would have made it doubly clear that the warrior's six-pack in fact represents a body-contoured breastplate made of beaten bronze. Almost invisible scratches in the marble had once acted as guidelines for the painting of the undertunic's pattern, and later weathering marks indicate that several different colors had been used to fill it in. The colors actually used on the reconstruction are hypothetical, based on other painted statues of the period. The marble of the breastplate might have been gilt, as a great many ancient sculptures were, but its gleaming metal could also have been rendered in shades of yellow.
• A marble nude, presumed to represent the god Apollo, survives in a museum in Kassel, Germany. The glowing whiteness we now see probably has nothing to do with how the work originally looked. The marble is almost certainly a Roman copy of a Greek original made hundreds of years earlier, about 450 B.C., perhaps by the great innovator Phidias. It would have been cast in bronze, like perhaps two-thirds of all Greek statuary -- almost every single piece of which has long since been melted down.

It's almost certain that the sculptor would have polished his figure to some kind of brassy sheen and added suitable accessories to it. In a bronze reconstruction in Kassel, the metal has been buffed and varnished to the point of imitating solid gold -- which, we know, was the prestige material for making monumental sculptures in the ancient world.

• The Augustus of Prima Porta, a marble sculpture of the Roman Empire's first emperor, was discovered in 1863 and is now in the Vatican Museums.

"Can you imagine the family-values, back-to-basics, republican emperor Augustus ... represented by something that looks like a cross-dresser trying to hail a taxi?" says Fabio Barry, an art historian at the University of St. Andrews in Scotland who's not overly fond of the Prima Porta sculpture's colored reconstruction. Barry, who is an expert on the history of marble and worked for a time in Washington, D.C., insists that the Romans cherished the whiteness of fine marble as an important symbol of light and purity. He doesn't deny that the precious Parian marble of the Prima Porta statue would have had some tints on top of it -- the colors noted when the piece was first unearthed were confirmed when it was cleaned in 1999 -- but he cannot buy their wildly unsubtle reconstruction. "I'm vehemently against any notion that people in the past were stupid or didn't have taste." Vinzenz Brinkmann, leader of the recent work on color in antiquity, doesn't disagree. He has a house on the Greek island of Paros, and often visits its ancient quarries. Their Parian marble, he raves, is "whiter than sugar and more beautiful than snow." And he says he's almost sorry there's such clear evidence that the Greeks and Romans often covered it in paint.

• A bronze head of a boy, cast by Roman artists about 20 A.D., survives in the Glyptothek collection in Munich. Eyeless and dark green, it represents our classic vision of classical art -- and one that's largely wrong. A bronze reconstruction shows it with the polished surface it once would have had; ancient texts refer to athletes' skin as glowing like "a well-mixed bronze," and to how sculptors labored to achieve lifelike colors in their metals. The reconstruction also re-creates the kind of inlaid eyes the sculpture had when it was found in the 1790s -- they were lost early on -- and the golden lips and eyebrows that still show traces on the Munich head. (Other ancient bronzes used polished copper inlays to represent red lips and nipples and even bloody wounds.) The dark hair is just a guess, but it evokes the broad range of finishes that ancient sculptors would have used for realist effects.