Emphasis by Color Contrast

Rainbow necklace. Ad (detail). Pamplemousse. 1979. Boucheron

From Parkland library, "Advertising, Reflections of a Century" by Bryan Holme
I think this ad serves a good function giving attention to the jewelry. You think, "Is there a necklace on that cat?" and then you obviously look at it, observing the bright shining colors in contrast with the black. I also think the lighting from the left does very well to draw the eye in a natural motion. The image is also very  symmetrical by being just a simple picture of a cat, which does all the better at creating focus on the product of interest.