will increase contrast in a dark subject, whereas decreasing exposure may increase contrast in a light gray scene.

increasing exposure

Refraction

translucent

that strikes it: it can transmit, absorb, or reflect that photon.

The subject can do three things to a photon

Absorption and reflection are both more major influences on

direct transmission, in which light passes through a material in a predictable path.

Light rays from a low-contrast source strike the subject from many different angles.