>> The statues depicted in the ancient artworks appear to be very delicately painted, often with large portions of the surface left white. A well-known example is the depiction of a statue of Mars at the House of Venus in Pompeii.
Oh, I see, if you look at the statue with the right eyes it's really obvious what they did. They started with a white primer then gave it a red-tinted wash all over, thinned down for the body parts so that they look flesh-coloured (ish... ) and progressively darker for the spear, helmet and shield, then the cape, and then the hair. This really helps to keep the mo... the statue together in terms of colour, and it's very efficient since the entire palette is tones of a single tint. I guess they gave the helmet and the spear the old non-metallic metal treatment, then they highlighted the helmet, the cape, the shield and the spear, and blended the feathers on the helmet.
That's a really classically modern paint job that you might find in any miniature painted to modern miniature-painting standards [1]. In fact it's surprisingly modern, I'd even go as far as to say that the one-tint wash job is positively avant-guard. I'm certainly trying that next time I paint a model with nice, big, flat areas like that one... like the statue, I mean.
>> I have given an example of this below a famous mosaic depicting a statue of a boxer, from the Villa San Marco in Stabiae. Note the subtlety of color recorded by the mosaic, in which the boxer is reddened and sunburned on his shoulders and upper chest, but not his pale upper thighs. There is nothing here to suggest that the statues depicted would have struck a modern viewer as garish.
Oh and here I guess they started with a zenithal primer, with the lighting coming from below and the right, then they did some dry-brushing with a darker tint. Nice job!
No but seriously, it's a bit dumb to think that the ancients would just apply a thick layer of basecoat and call it a day. If we do all those elaborate things today on plastic miniatures, I can imagine what they did.
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[1] https://youtu.be/92YtIbpG6EE?si=ezhOx9u5Ek6FW3M-