Almost any type of light can be used for portrait photography. This includes natural light, such as the sun, as well as artificial light, such as electronic flash.

The sun, with its different forms of illumination-daylight, skylight, and window light-is the major source of natural illumination for portraits. The sun is used primarily for location portraiture.

Most types of artificial light can be used for portrait photography as long as the intensity is sufficient to permit short exposures. Short exposures are desired because it is difficult to keep a subject motionless during a long exposure. For color portraits, the color quality of the light source should be the same as that for which the film is balanced. Of all the artificial light sources available, electronic flash is the best light source for portrait photography because of the following:

It provides a large output of light without the annoying heat produced by incandescent lights.

The extremely short duration of the flash stops subject movement.

The color temperature of the light is compatible with daylight.

They are as versatile as other light sources.

Electronic flash units specifically designed for portraiture usually have tungsten modeling lamps located near the electronic flashtube. These modeling lamps provide constant, low-intensity illumination on the subject or background. This allows you to see the lighting effect that will be produced when the electronic flash units are fired.

BASIC LIGHTING UNITS. Studio electronic flash units are divided into two broad classifications: those that project a relatively narrow cone of concentrated, crisp light and those that project a broad area of softer, more diffuse light.

Spotlight. A spotlight projects a narrow, highly concentrated, crisp beam of light, produced by an undiffused clear flashtube. A Fresnel lens or a small reflector with a mirror finish is used to direct and focus the light. The light produced by a spotlight is very much like direct sunlight on a clear day. The light rays are nearly parallel and are not diffused. The shadows cast by a spotlight are hard with sharply defined edges that add crispness. A spotlight is usually used to highlight or stress a feature of the subject or as a hair light or background light.

Floodlight. A floodlight produces a broad area of partially diffused, soft light, very much like sunlight on an overcast day. A frosted globe is used over the flashtube, so the light produced is initially diffused. The light is further diffused by the reflector that causes the light rays to cross and interfere with each other. The rays, projected from the front of the flashtube, however, are not as diffused and have a crisper quality. The light, produced by an electronic flash floodlight, has a crisp quality at the center and a softer quality toward the edge. When you want to use just the softer part of the light, allow only the outer part of the light beam to fall on the subject. This technique is called feathering the light. When you want the entire beam of light to be diffused and very soft, use a diffusing screen over the light source. There is also a type of light unit known as a capped light. This type of unit has an opaque metal cap placed in front of the flashtube to block specular light from reaching the subject. All light projected by a capped unit is diffused.

A floodlight is usually used as the main (modeling, or key) light in portraits, especially where a soft effect is desired. It is also used as a fill light because a fill light is always diffused.

ACCESSORIES. Many accessories are available for use with studio lighting units. Accessories are important tools that make your portrait lighting units either more dependable or more versatile. They aid in creating the exact lighting affect you want. Common accessories are as follows: diffusers, barn doors, snoots, and umbrellas. If accessories are not available, compromises in the lighting can alter the effect and quality you desire.

Diffusers. You use diffusers when you want to change specular light to a softer, more diffused light. Diffusers are made of translucent or mesh materials that, when placed in the light beam, break up or diffuse and soften the light. The finer the mesh, the more diffused the light. When only a small amount of diffusion is needed, a wide mesh material, such as gray window screen, works well. For more diffusion, two pieces of screen can be placed together slightly out of alignment, or a finer mesh material, such as white cheesecloth, can be used. Floodlights initially produce a fairly diffused light, but diffusers may also be used with them. Diffusers can be mounted on the light unit or placed somewhere between the light unit and your subject.

There are many reasons for using a diffuser instead of a light that already produces diffused light. A diffuser may be needed when you do not have a soft light available. A softness that is between two different light sources may be needed, or you may want to produce a small area of diffused light that can only come from a spotlight with an installed diffuser.

Barn Doors. Barn doors are made from opaque material. They are usually made of metal, painted black, and attached and hinged to the front of a light unit. They can be positioned to block or feather a portion of the light produced by the unit. Barn doors are made for both spotlights and floodlights. They are good accessories for controlling spill light.

Snoots. Snoots are cylinders, open at both ends, usually made of metal and painted black. They are used at the front of a spotlight to limit the size of the circular area projected by the unit. Short, wide snoots give a large circle of light. Long, narrow snoots give a narrow circle of light. A cardboard tube or black-rolled paper can be used for a snoot when you need to improvise.

Umbrellas. Umbrellas work much like the reflectors used on floodlights and provide an excellent means of converting specular light into soft, diffused light. They are used with any light source. The light unit is pointed away from the subject; the umbrella is

7-4 attached in front of the light and reflects or bounces the light back and onto the subject. The reflected light falling on the subject is softer and more diffused than the light originally emitted by the source.

The reflecting surface of the umbrella determines the quality of the light. Umbrellas are usually made with a matte, white surface that provides a very soft, completely diffused light. Some umbrellas are constructed with a shiny, metalized surface. Metalized umbrellas throw a somewhat specular light, but the light is softer and spread over a larger area than the light emitted by the original light source.

FILM FOR PORTRAITS

For black-and-white portraits, black-and-white panchromatic film is generally used. With a pan film, the appearance of any red spots, veins, or redness in the subject's skin is apparently reduced in the final print, because of the sensitivity of the film to red. Conversely, an orthochromatic film can be used when the texture of a man's skin, especially an older man, is to be emphasized.

When you select a color film for portrait photography, there are two important considerations: What type of product is to be produced and what is the color of the light source?

Another factor to consider in selecting a film for portraiture is the ISO film speed in relation to the intensity of the light source. A slow film can be used successfully with a light source that has relatively high intensity, such as an electronic flash unit. When the same slow film is used with a light source that has relatively low intensity, an extremely wide aperture must be used. When a fast film is used with a high-intensity light source, a smaller aperture is required, increasing the depth of field which may not be desirable for portraiture.

When you are shooting portraits, do not be stingy with film. With a medium-format camera, you have 9 to 15 frames to work with. When you have the commanding officer or the admiral in the studio for a portrait, shoot at least the entire roll. Never shoot just three or four frames. Film is cheap and you want to provide the customer with a variety of poses and expressions to choose from.