from some luminous source.
Black cloth or areas of dark forest, for instance, absorb
more light than objects such as a white sheet or a coral
sand beach. When light comes in contact with the
surface of an object, a certain degree of reflection, and
some absorption, always takes place.
When an object is opaque and the light is not reflected,
it is absorbed by the object. When light is absorbed, its
energy is converted and it no longer exists as light.
of white light and reflects the red waves. A lawn appears
green because the grass blades absorb the red and blue
rays of light and reflect the green rays.
proportions of the colors of light. Varying reflective
powers account for their differences. White is highly
reflective, while an object of absolute blackness, no
on film except by contrast.
some medium they encounter. When objects can be
clearly seen through the medium, the medium is
in a regular, or uniform, pattern. When the medium
transmits light but breaks up the orderliness of the
pattern, sending the transmitted rays in many directions,
the medium is translucent. In other words, a medium is
said to be translucent when light is visible through it, but
objects are NOT clearly distinguishable. Thin fabrics
that allow the passage of diffused light (fig. 1-7). One
important form of transmission is termed refraction.
substance of different density is called refraction.
Refraction enables a lens to form an image. Without
refraction, light waves behave as X rays and pass in
straight lines through all suitable substances without any
control of direction, and only shadow patterns can be
at different speeds in different transparent substances.
The speed of light in each transparent substance is called
Basic Photography Course