The word photography is derived from the ancient Greek words, "photos" and "graph" meaning "light writing". To understand light the photographer must be fully conversant with its qualities and behavior. In mastering the medium the photographer learns to take control over the creation of the final image. This takes knowledge, skill and craftsmanship. It can at first seem complex and sometimes confusing. However, with increased awareness and practical experience light becomes an invaluable tool to communication.
Seeing Light
In order to manage a light source, we must first be aware of its presence. Often our preoccupation with content and framing can make us oblivious to the light falling on the subject and background. We naturally take light for granted. This can sometimes cause us to simply forget to "see" the light. When light falls on a subject it creates a range of tones we can group into three main categories. Highlights, Mid-tones and Shadows.
Each of these can be described by their level of illumination (how bright, how dark) and their distribution within the frame. These are in turn dictated by the relative position of Subject, Light source and Camera.
Introducing Light
The major difference between studio and location photography is the studio itself has no ambient or inherent light. The photographer starts with no light at all and has to previsualise how to light the subject matter and what effect that light will have upon the subject. Studio photographers have to conceive the lighting of the subject rather than observe what already exists. This requires knowledge, craft, observation, organization and discipline. Good studio photography takes time, lots of time, and patience.
Understanding the Nature of Light
In order to make the best use of an artificial light source, we must first be aware of how light acts and reacts in nature. Observation of direct sunlight, diffuse sunlight through cloud and all its many variations will develop an understanding of the two main artificial studio light sources available. A spotlight (point light source) imitates the type of light we see from direct sunlight, a hard light with strong shadows and extreme contrast. A floodlight (diffuse light source) imitates the type of light we see on an overcast day, a soft diffuse light with minor variations in contrast and few shadows. To understand light fully it is essential to examine its individual characteristics.
- Source
- Intensity
- Quality
- Color
- Direction
- Contrast
Source:
Ambient
Ambient light is existing natural or artificial light present in any environment. Ambient light can be subdivided into four major categories:
- Daylight
- Tungsten
- Fluorescent
- Firelight
Daylight
Daylight is a mixture of sunlight and skylight. Sunlight is the dominant or main light. It is warm in color and creates highlights and shadows. Skylight is the secondary light. It is cool in color and fills the entire scene with soft diffused light. Without the action of skylight, shadows would be black and detail would not be visible. Most color films are calibrated to daylight at noon (5500k). When images are recorded at this time of the day the colors and tones reproduce with neutral values, i.e. neither warm nor cool.
Tungsten
A common type of electric light such as household bulbs/globes and photographic lamps. A tungsten element heats up and emits light. Tungsten light produces very warm tones when used as the primary light source with daylight film. Underexposure occurs due to the lack of blue light in the spectrum emitted. The orange color cast can be corrected with a blue filter if neutral tones are desired; however, correct color can be achieved without filtration if used with tungsten film. Digital cameras neutralize color casts introduced by light sources other than daylight by adjustment of the white balance to the dominant light source of by capturing as RAW format and correcting in post production.
Fluorescent
Phosphors inside fluorescent tubes radiate light after first absorbing ultraviolet light from mercury vapor emission. The resulting light produces a strong green cast not apparent to the human vision. If used as a primary light source the results are often unacceptable due to the broad flat light and the strong color cast. Underexposure is again experienced when using this light source and the cast can be difficult to correct. Fluorescent light flickers and causes uneven exposure with focal plane shutters. To avoid this shutter speeds slower than 1/30 second should be used.
Firelight
Light from naked flames can be very low in intensity. With very long exposure it can be used to create atmosphere and mood with its red tones.
Artificial Light
Tungsten (non-domestic)
There are many variations of non-domestic tungsten light sources used in a photographic, film and TV studios. They all fall into two major categories, floodlight and spotlight. The majority have a color temperature of 4300 - 3400K, and are compatible with tungsten color film and any black and white film. A simple floodlight would have an output of 500 watts and a basic focusing spotlight around 650 watts.
