These basic qualities of light are; INTENSITY, FORM, COLOR, DIRECTION and MOVEMENT.

You’ll also recognize when there’s no pizzazz to the light and, most likely, you will not make so many disappointing images. Photography is “writing with light.” So, let’s build our conversation about lighting on five fundamental characteristics of light: Direction, Intensity, Color, Contrast, and Hardness.

The primary properties of visible light are intensity, propagation-direction, frequency or wavelength spectrum and polarization, while its speed in a vacuum, 299 792 458 m/s, is one of the fundamental constants of nature.

Theories of Light

• Newton’s corpuscular theory.
• Huygen’s wave theory.
• Maxwell’s electro magnetic wave theory.
• Planck’s quantum theory.

Wave-Particle Duality of Light. Quantum theory tells us that both light and matter consists of tiny particles which have wavelike properties associated with them. Light is composed of particles called photons, and matter is composed of particles called electrons, protons, neutrons.

In the seventeenth century two rival theories of the nature of light were proposed, the wave theory and the corpuscular theory. The Dutch astronomer Huygens (1629-1695) proposed a wave theory of light.

two theories

Christiaan Huygens

Christian Huygens

But, the Dutch physicist, Christiaan Huygens believed that light was made up of waves vibrating up and down perpendicular to the direction of the wave propagation, and therefore formulated a way of visualizing wave propagation. This became known as ‘Huygens’ Principle’.

Waves come in two kinds, longitudinal and transverse. Transverse waves are like those on water, with the surface going up and down, and longitudinal waves are like of those of sound, consisting of alternating compressions and rarefactions in a medium.

Based on the orientation of particle motion and direction of energy, there are three categories: Mechanical waves. Electromagnetic waves. Matter waves….Electromagnetic Wave

• Microwaves.
• X-ray.
• Radio waves.
• Ultraviolet waves.