Hard Light & Soft Light
The first thing to consider in lighting a scene is the character of light itself. Light can be hard, soft or gradations between. Hard light casts strong, well defined shadows and the softest light is shadowless. Hard light is generated from small sources whereas soft light comes from large ones.
A cinematographer would be unwise to judge a style of lighting on its own merit. Sometimes the qualities of soft light that seem less interesting are just the qualities needed to serve the story. The argument between hard and soft light is kind of weak because in a sense you really make your judgment based upon whatever the story is.
The hardest source of light known in nature is the noonday sun; an overcast sky is the softest source known. It is as a diffusion material has been stretched from horizon to horizon. The illumination comes from all directions and cancels out the shadows. The hardest light in general use is the arc. Its light, created between two carbon electrodes, is smaller and brighter than the filament of an incandescent bulb A Fresnel lens is used with an arc to bring the light into a narrow beam (arc sources are the Cinelight HMI lights). Incandescent lights with Fresnel lenses also fall in the range of hard lights (like Cinelight Fresnel Junior series).
Open-ended lights can be hard or soft, depending on the size of the reflector and on the type and positioning of the bulb. The softest are boxlike soft lights and a variety of lighting instruments made in the studio that consist of rows of bulbs behind a diffusion screen (we can give an example by pointing to Cinelight SpaceLight series). Even softer sources can be created by placing very large diffusion screens in front of conventional lights or by bouncing light off large reflective screens onto the subject. Soft light also comes from naturally broad sources, like a cluster of fluorescent tubes, which cannot create a sharp shadow (an example of this kind of fixtures are the CineFlo and D-Lite series for location shots and the Studio Cool lights for studio productions).
Soft light produces much lower light levels for the same wattage used than hard light and it falls off with distance much faster. Many leading cameramen developed a style of lighting that utilizes soft light as the chief light source in a majority of scenes. Other equally distinguished cinematographers continue to favor the predominantly directional focusable key lights; these should be chosen carefully for a particular area or function. There is, of course, a middle ground, which might be to use predominantly soft light but accentuate modeling with some harder sources.
Soft light technique is basically area lighting, which creates a more natural look. Since less equipment is involved, it actually helps to keep the production moving at a better pace, especially when less professional actors and directors are involved. Soft light is less specific to a single area, allowing actors more freedom of movement on the set without “missing” their light. These attributes become rather important with today’s budget considerations. There is a drawback to using soft light, however. It is difficult to control because, originating as it does from a large source, it spreads in all directions. Therefore huge black screens (flags, teasers) are needed to cut off the light from certain parts of the set.
Soft light falls off rather sharply also; therefore it must be positioned relatively close to the subject. That becomes problematical in a wide angle shot when a large area of the set is in the frame.
Soft light gained its popularity because it gives the scene a more natural, less “filmic“ look than hard lighting. At the same time it has a danger of lacking character. In the final analysis, it is just another “brush” to paint with, but not the only one.
Hard light also gained an important justified place in both still and motion pictures, because even though soft light is more convenient to work with, lighting too soft makes a particular scene boring for the viewers. Flat lighting (also known as high key lighting because there’s a high ratio of key to fill) provides very little modeling. Evenly lit flat areas often need to be broken up with shadows. So the difficult thing is really to light softly but to create a contrast at the same time, in order to create a sense of shape and depth.
In real life we are used to having only one shadow. On the set each hard light casts a shadow. Multiple shadows on film are distracting. Cinematographers take great care to minimize multiple shadows. The creation of softer or harder shadows to take the light away from certain areas constitute methods of controlling light and creating mood in the scene. A large arsenal of light-restricting devices has been developed over the years specifically for hard lights; they are often too small to be used with soft light. From ever present scrims and barndoors on the lamps, to cutters, fingers, sticks, they all help to keep the light from being in one tonality. They come in a variety of sizes and shapes to hold back the light from carefully selected and often very small areas.
In immediate and practical terms, the character of light will be initially designated by the time of day. Day interiors are affected by sunlit windows. Many cinematographers call sunlight coming through the windows “sourcy” light, meaning that it is well defined in its origin. Most daylight scenes are very soft, except for harsh sunlight coming through the window, which is sourcy, and should be handled like a bounced light. But night interiors and night exteriors are, in real life, defined by shadows. Creating varying degrees of softness and directionality becomes one of the important methods used to create mood through lighting.
There is a tendency to think that the philosophy is soft or hard lighting, but in reality the philosophy is what film you are doing. Basically you should have at your disposal any range of lighting styles. One has to have practical experience in both styles of lighting to be able to mix and match them effectively.