I see what you are saying now, and I agree, Virgil.
Bouguereau uses what paint does best, being translucent. Paint the thickest patch of paint on glass, hold it to the light, and voila, it's translucent. The only thing I might add is that this procedure is a tendency rather than a method. For example, I don't think Bouguereau painted everything more chromatically as a base for neutralized passages. He instead, I believe, used the technique selectively and in areas where the ruddy areas are most telling, like the extremities, cheeks, and top planes (the veins are always in the crevices and are instead greenish). Also, because he paints in veils, some of the added chroma underneath was achieved by the nature of paint itself on a light ground. By continuing to refine the image by adding additional layers, Bouguereau was able to achieve a certain fleshiness by method, for free as it were, much like
Fantin-Latour achieves the silvery quality of flower petals by painting them on a darker ground.
