Origin
According to the Chinese philosophy, the concept of yin-yang ( traditionalChinese : 陰陽 ) , which is often called "yin and yang", is used to describe how seemingly opposite or contrary forces are interconnected and interdependent in the natural world; and, how they give rise to each other as they interrelate to one another. Many natural dualities ( such as male and female, light and dark , high and low , life and death, and so on ) are thought of as physical manifestations of the yin-yang concept.
Yin and yang are actually complementary, not opposing, forces, interacting toform a whole greater than either separate part; in effect, a dynamic system.
Everything has both yin and yang aspects, ( for instance shadow cannot exist without light ). Either of the two major aspects may manifest more strongly in a particular object, depending on the criterion of the observation.
Yin and yang like inseparable as body and shadow. This is basic on dualism use for monochrome photograph about what I think of Eastern philosophies.