My own observation of Bouguereau's paintings (and Boucher's), and my own experimentation with it lead me to believe beyond doubt that it was a planned effect rather than an accidental one. The shadows on the flesh of both figures in WB's Young Girl Defending Herself against Eros are translucent greys applied over a warmer, lighter, higher-chroma underlayer that gives them their color, which underlayer also shows through to varying degrees in the middletones, where the greyer tones over it are approximately the same value as the underlying color, or in some areas slightly lighter, blending seamlessly with the darker greys of the shadows on the one side, and with the more opaque lights on the other, apparently all done wet-into-wet over the dried underlayer of stronger color. It is too meticulously worked to have been done other than deliberately, with the ultimate degree of finesse that characterizes Bouguereau. That painting is only one of many in which it is fairly easy to read, if one is looking for it, but it provides an excellent example. There is a reduction of this painting in the Getty, and the effect can be seen in that (smaller) version of it as well.
Parkhurst mentions this approach as a method, without mentioning Bouguereau's name in connection with it, indicating that it was not necessarily unique to Bouguereau, but one of a number of variations of indirect painting that was in more or less common use at that time. Bouguereau does seem to have mastered it, refined and perfected it to a higher degree than anyone else, and it is one of the things that sets him apart from the legions of other fine painters of his time.
Virgil
