I think the most relevant answer to this is revealed by the date of the picture, which puts in a period in which Weston was in transition from the studio portraits and "pictorial" (i.e. painting-like) work of his early career to the mature abstract images. In the later phase, he set himself the target of producing abstract images which revealed "the thing itself and also more than the thing" (quote from memory). By this, Weston's own ultimate benchmark, the image of the eggplant, although a valid exercise in itself in tone and texture, falls short of Weston's best by the simple virtue of being too literal and showing ONLY "the thing itself."
Originally Posted by Christopher Colley