3 - Fundamentals of Lighting Optical Control

Reflection (and Reflectors)

Process - part of the light falling on medium leaves that medium from the incident side

Lacquer, Brilliant White

What Surface Material?

87-88% Reflectance Factor (Highest)

White

What Surface Color?

70-85% Reflectance Factor (Highest)

Brick, dark

What Surface Material?

10-15% Reflectance Factor (Lowest)

Black

What Surface Color?

5% Reflectance Factor (Lowest)

Specular

reflecting in polished surfaces

Specular

The angle between the reflected ray and the normal to the surface will be equal to the angle between the incident ray and the normal.

Specular

Spread

If a reflecting surface is not smooth (ex. corrugated, etched, or hammered), it spreads parallel rays in to a cone of reflected rays

Spread

Diffuse

If a material has rough surface or is composed of minute crystal or pigment particles

Diffuse

Compound

reflectors that exhibit all three reflection components (i.e. specular, spread, and diffuse) to varying degrees

Diffuse and Specular

Diffuse and Spread

Specular and Spread

Refraction (and Refractors)

Change in the velocity of light (speed of propagation, not frequency)

Refraction (and Refractors)

Occurs when a ray leaves one material and enters another of greater and lower optical density

Interference

When two light waves of the same wavelength come together at different phases of their vibration, they make up a single wave

Interference

The combined wave’s amplitude is between the difference and the sum of the amplitudes of the two

Diffraction

a phenomenon that occurs when light passes by an obstruction, producing an indistinct shadow of the edge

Diffusion

Breaking up of beam of light and he spreading of its rays in many directions by irregular reflection and refraction

Diffusion

from crystalline particles, droplets or bubbles within a transmitting medium

Absorption

occurs when a light beam passes through a transparent or translucent medium

Absorption

occurs when a light beam also meets a dense body

Red

A ____ object reflects red and absorbs other colors of white light

White

A ______ object reflects all colors of white light equally

Black

An objects is seen as ____ if it absorbs all colors of white light