I found this article in the New Yorker interesting:
We have exchanged views on how ancient sculpture was painted in the Aegina thread http://discourse.textkit.com/t/visit-to-greece-especially-aegina/16208/1
There is a discussion in the NY article of how the colour of statues is affected by the material used in reconstructing the statues themselves. Plaster affects the results by making the painting seem flat. Layering the paint as in Oil painting and reconstructing on marble produces a more translucent effect. Modelling the statues digitally is one way forward. At the British Museum Ashurbanipal exhibition some of the reliefs were coloured using projections. The colours were added successively which helped (me at least) to “read” the panels.