Not sure I can help too much. In a real scene, the colors of the cloth will reflect onto the apple. And the colors of the apple will reflect into the cloth. In the highlights this reflection is minimal. In the shadows, even the small shadows in the cloth texture, this reflected color would be more apparent. With the cloth, a "dull" surface, this would tend to desaturate the reds, (a red color illuminated by a green light). With the more shiny apple, the shadows facing the cloth would take on a reddish surface glow. The shadow around the stem is not facing the cloth, so would be unchanged. Even though the cloth is a dull surface, it will have a few green specks. With wet paints, one would "pull" some of the colors together.