Attributes of Light
What are the Attributes of Light?
Brightness, size, beam pattern, color, direction, quality (specular/ diffuse), and contrast are the major attributes found when lighting a subject(s).
The brightness of the light source is simply the light’s intensity and how much light it emits. Brightness is measured in either f-stops or t-stops, with a light meter. Light sources closer to the subject(s) your shooting will of course appear brighter than if the light source was further away from you subject(s)
The size of the light source is a major factor, considering if the size is large enough to light your entire subject(s). If you’re wanting to add a twinkle to someone’s eye (using an eye light), the size of the light source will be smaller than, say, your key or fill light on the same person.
The beam pattern of the light creates different shapes and even shadows that may fall on the subject(s). Is the light focused in on one spot? If you’re using a lensed light source such as a Fresnel, and the subject is further away from the source, this beam will be more noticeable.
What color temperature is the light emitting? Tungsten and daylight are only a couple and the most commonly known or used. However, there are various color temperatures on the Kelvin scale, all ranging from 0 K (midnight) up to 25,000 K (shade or north sky). Read more about color temperatures here.
The direction, or angle at which the light source hits the subject(s) should always be considered. Not only will the direction of light, if properly placed on the subject, look appealing; but the direction of light also helps establish mood. Considering direction, there is an imaginary axis between the light source on your subject (light source/ subject) relative to the axis at which the camera is positioned (camera/subject). If the light source is too low, the shadows on the subject will be high; and if the light is positioned too high, the shadows will fall low. A common angle for a key light is positioned at a 15 to 45 degrees, both horizontally and vertically, from the camera lens. However, on a set there are other places to place light sources, and these light angles are usually classified as top, side, kicker, and 3/4 back.
Soft vs. Hard
The quality of light is usually describing whether the light is diffused (soft) or specular (hard). This is one common attribute found in light, and one that most beginners are aware of. Diffused light is usually determined by the large size of a light source, or a diffusive-type of material over the light source that scatters the light in various directions. The result, soft light creates softened shadows with a slow fall-off edge, can hide wrinkles, and is commonly used in high-key lighting situations, such as in comedies. Hard light is the opposite, for hard light creates sharp fall-off lines that create sharp, angular shadows. This type of lighting brings out details and exaggerates textures and can help establish off-beat moods.
The contrast of lighting isn’t used to apply to the light source itself, but rather to the contrast the light creates upon the subject(s). Contrast refers to the difference between black and white; however, colors also have contrast between them. Shadows have contrasts as well. For instance, hard lighting situations exaggerate, or increase contrasts. The less fill light on a shadow, the more contrast on the subject(s). The more fill light, the less contrast. Therefore, the lighting ratio between the key and fill is an important consideration when determining contrast.