Characteristics of Light

The subjective interpretation of an object is formulated by light’s characteristics. This information that light presents is placed into different categories. Each of these areas explores and qualifies:

INTENSITY is the amount of light that is falling upon a subject from a lighting source

The Sun and a candle are just two sources, One strong, one weak.

Light's intensity is measured in Foot-candles.

Foot-candles:The amount of light that is radiated
within one cubic foot of the source.
A light meter is needed to measure the intensity

QUALITY is an interpreting factor: Is the light hard or soft?

• HARD LIGHT: strong, bright and direct with dark and crisp shadows.
• SOFT LIGHT: diffuse, not as directional. Light or no shadows.
• SEMI-DIFFUSE LIGHT: a midway point. Directional diffuse light. Moderate shadow definition.

REFLECTION:

The ability of an object to bounce light. The reflective property of an object is defined by it's surface texture: A shiny surface will have a greater reflective index then that of a matte surface

The scientific law of reflection is: "The angle of incidence equals the angle of reflection."

REFRACTION:

The ability of an object to bend light.As light passes through an object, the path it travels will be altered based upon the properties of the object.

Examples: Water, camera lens, and diffuse material

ABSORPTION: (This is not a characteristic of light.)

Is based on an object’s specific color properties. Its abilities to except or reflect a specific color wavelengths. Absorption is a determining factor when making a subjective observation of an object.

The above mentioned characteristics will help in the evaluation and implementation of lighting. Whether you are shooting with natural light or creating a lighting design the vocabulary remains the same. Lighting is a subjective interpretation. It sets a mood and evokes emotion from the viewer. The choices that are made will define the aesthetic characteristics of your scene.

 

Contrast

Lighting Contrast is the difference between the lightest and darkest areas of a subject. These differences are known as tonal ranges. Other determining factors are quality of light, the subject's shape, color and the light direction. Each of these will affect your judgment of a scene.

Tonal Range is the density of the dark to light areas within a scene. The same factors that effect lighting contrast will also affect tonal range.  

Tonal range

Color and Contrast: The presence or absence of color will strongly effect the lighting contrast. Colors create their own contrast. The further apart the colors are in spectrum the greater the contrast.

Color Intensity or saturation is another area that can be manipulated by light. A light striking an object from different angles will produce tonal values within the color.

Subject Properties: The physical properties of a object react differently to light.

• The surface of an object can be glossy, matte, flat and textured.
• The material the object is made of will be opaque, transparent or translucent.

A black opaque, glossy vase will absorb the color wavelengths while reflecting the light's intensity.

FALLOFF: The transition from light to dark is based upon the quality of light used.

• Hard light has a quick falloff with no gradation between light and dark.
• Soft light has a slow falloff that produces a gradation between light and dark.

Effect of Light Direction

The angle and direction that light falls on a subject has a considerable influence on its appearance. There are three directions:

Frontal lighting comes from the camera position 

The illumination from a light reveals the most details in a subject, while the shadow and texture areas are minimized. Shadows fall away from the camera and are hidden by the subject.

Side-lighting is at a right angle to the camera. 

It reveals and enhances the depth of a three dimensional subject. Over all detail is reduced. Shadow areas appear and sculpt the face. Textures areas can be enhanced.

Back-lighting/rim-lighting comes from opposite the camera. 

Backlighting will produce a silhouette of the subject. The subject will appear as a black shape with no details. Backlighting/Rim lighting is used to separate a subject from a dark background. Both of these techniques produce similar results but are used in different applications.

Function of Lighting

The chief function of lighting is to understand and implement the affects of light when creating images. A scene can convey different meanings to your audience. For example:

A woman seated near a window:
What time of day is it, morning, afternoon, or night?
Are there lights on in the room?
If so, what types of lights are they?
Does the light from the window work as the main source of light
or is she lit by a practical lamp within the room?
What color is the room?
What is the mood you want to set?

The above questions are just a small sample of areas that need to be addressed when creating an image. Lighting’s function and objective is achieved through the control of light and shadows. Learning to control light will influence what type of emotional impact your image will present. The two major styles that help to establish an atmosphere or mood are:

High Key Lighting: A scene that is bright with little contrast between light and dark areas is considered high key. Television news and Sitcoms are good examples of high key lighting. Low Key Lighting: A dramatic and moody scene that is dominated by dark tones. Low key lighting has a strong contrast between light and dark areas. High drama and suspense films are good examples of low key lighting.

Each of these styles has a unique aesthetic value. When choosing a style, one must consider what information one would like to convey to an audience about the subject or story. The decisions involve the understanding of light, color, contrast, exposure and lighting instruments. Creative freedom begins with a solid foundation.