I did some more studies and I specially like the way the way the last pink floating ball has come out. It is of a matte surface in outdoor light. Matte surfaces absorb light and have a uniform gradation from light side to shadow side. Here, the color gradation is also visible from orangish on the left, sunlight side to a slightly more saturated pinkish salmon tone at the centre and more of a reddish violet on the right top side which is catching the skylight. The bottom shadow side shows a bit of the reflected light of the green grass hitting it from below which also gradates from left(warm) to right(cool).
Reflective surfaces reflect light from light sources as well as other surfaces around them and values on them jump suddenly and donot have a uniform gradation. Highlights are sharp and take on the color of the light source except for metals (gold always keeps a dull yellow highlight, copper an orangish one..regardless of color of light source)
Translucent surfaces allow light to pass through them partially. As the light passes through layers of tissue in a grape, the light becomes more chromatic on the other side as it picks up the color of the material. The shadow is very slight, maybe a sliver across the middle. In semi transparent colored glass (maroon ball) the colored light spills out on the other side and makes for a light reflection in the cast shadow.
Pearls have all kinds of pastel colors bouncing off them, no deep shades. Soft highlights.
Every material has its own way of absorbing and reflecting light which gives it its own unique visual appearance.
Watercolor Journal 