The effect is preternatural--bringing an immediacy to the past that is paradoxically fresher than the present--and is accomplished with careful attention to the texture of materials and the play of light on surfaces, modulated with projected shadow.
Even the maroon background is enlivened with a subtle grid texture that reflects myriad points of background light while lending the frieze the suggestion of gilded relief-carved marble (by then it was known that ancient Greek marbles were originally painted and gilded).