The teacher asked me to do my photography homework:

Reflectivity is the degree of reflection of light on an object.

Low reflectivity: generally something dark. Such as coal

High reflectivity: such as white walls, snow, mirrors (of course, mirrors are more directional)

The reflectivity is between the two.

These three areas are the relevant reflection intensity parts.

For example, taking a photo of a person with black hair and wearing a white coat and gray pants will be found in all three areas.