Film Production - Lighting Equipment & Techniques
Filmmaking is all about capturing light. A bright light draws the viewers eye. A scene can be lit by available light (the sun, moon or existing light sources) or using powerful and expensive artifical light. The way a scene is lit influences how the audience will react emotionally to your movie.
The angle and direction of light gives your audience clues about where and what time of day the scene is taking place. Painters have long understood that the quality of light in a scene can hide or reveal things and influences the viewer's reaction.
In feature films the lighting is a high priority because how well the movie is lit influences how the audience perceives the production values of the movie and therefore the quality of the movie. Badly lit images can do more to make a film look amateuric than any with the possible exception of bad sound.
In documentary films the light is given much less consideration because it often isn't possible to control the light and audiences are used to documentary movies having a "news footage" look. A feature filmmaker can choose to use documentary lighting to create a sense of realism.
Quality of light
Light can be classified in several ways including:
- How sharp is the shadow?
- What is the angle of the light?
- How bright is the light?
- What color is the light?
- How many lights are there and how do they contrast in all the ways just listed?
A hard light, coming from a single small source such as the sun or a spotlight, creates a harsh appearance. They also create harsh shadows on the background as well as on the face and features of your actors. The prettiest actress can look homely in hard light.
A soft light, coming from a large area of lighting or many small lights, creates a soft, gentle or romantic look. It generally takes much more power to create the same amount of soft light compared to hard light. Many old films had to use hard lighting because the film was so insensitive to light.
The direction of light effects the audiences perception of the subject.
A film is rarely lit with a single light source. There are usually a minimum of four sources in a professionally shot film.There is a key light that provides most of the illumination on the subject and is typically at a 3/4 position. Next a fill light from the side fills in the shadows to soften them.
Key light only
Fill light only
The relative brightness of these lights is referred to as the contrast ratio of the lighting. Low contrast, where the two light are close to equally bright is a soft light. High contrast where the shadow fill light is much dimmer creates a harsh, hard light that is appropriate for villains and used much in film noir.
A third small, direction light illuminates the back of the actor. The light may be to the side or above. This light outlines the actors form giving a some three-dimensional appearance. It also puts a gleam on the actors hair and is therefore sometimes called the hair light. If the back light is the brightest light you get a dramatic silhouetted look which makes a great dramatic entrance for the hero or villain, or a very romantic look for the leading lady.
Back light only
These first three lights--key, fill and back--are sometimes referred to as three-point lighting. It consitutes the most pleasing and common way that people are lit, whether for films or formal portraits. Having an understanding and mastory of this three light combination will handle about 95% of the artificial lighting situations you encounter.
Complete 3-point light setup
At least a fourth light source is usually aimed at the background behind the actor to illuminate the setting. Otherwise the actors might look like they are floating in space.
You can also change the vertical angle of the light. Normally the key and fill lights are slightly above eye height. The back light in a studio would be above and behind the actor as they face the camera.
Top light creates deep eye shadows and is almost always unattractive. Unfortuneately that is often the only existing light angle you will find in many locations such as offices and stores. Low light creates the classic, and overused, monster lighting.
The lighting contrast ratio can be very misleading if you try to judge it visually. Both film and video cameras can't see the range of brightness in a scene that the human eye can see. The contrast ratio that is recorded on film or video always appears much higher than what you eye will tell you. You need to get very good with an exposure meter for film, or use a good video monitor when working in video to see what the lighting is really going to look like in the final image.
Shadows that appear to have detail to the eye will end up as totally black. Highlights will completely wash out, especially with video, to a very ugly, detail-less blob like glaring snow.
Generically movie lights are called units, heads, luminaires or heads. The light bulbs in them are referred to as lamps or globes. There are many additional names you will hear them called by experienced gaffers based on tradition or specific names given by manufacturers. I'll list them while I'm describing the various kinds of lights.
First a little bit of physics.
Lighting units are classified according to their color temperature. The sun has a color temperature of about 5000 degrees K. A typical tungsten light like you would have in your home would have a color temperature of about 3200 degrees K.
The "K" stands for Kelvin, a measure of temperature in celsius starting at absolute zero. You don't need to know that last part. Just remember that any lighting unit with a color temperature of 5000K or higher will match to sunlight and will be referred to as "daylight" balanced.
Any light unit with a color temperature of 3200K to 3400K will match to room lighting, but look very orange next to something that is lit by the sun or a 5000K unit, and referred to as "tungsten" balanced.
Lights are also classified by how much electricity they consume. While a typical room light consumes 100 watts of electricity a typical small spotlight might consume 1,000 Watts of electricity. Such a light unit would be called a 1K tungsten spot. (The "K" in this case is shorthand for one thousand.)
One more thing you need to understand is how light loses intensity at a distance. If you use a light meter to measure the light from a bare bulb hanging in a room at a distance of 1 foot, then measure it again at 2 feet you will discover that you only get 1/4 intensity reading as you double the distance.
Even putting a reflector behind a light source may increase the light intensity at any distance compared to the same light source without the reflector, but the light still falls off to 1/4 the brightness every time you double the distance. There are several lessons to learn from this experiment.
One is that you need to get light sources as close to your actors as possible. Another lesson is that if you want the object on your set to appear to be illuminated equally you will need to light each part of the set with lights that are very close to the same distance from what they are being used to illuminate.
As a safety precaution realize that most artificial light sources get hot and movie lights get extremely hot. The beam from a large spotlight can set fire to flamable objects and if shown through a household window will shatter it. Never touch a light instrument unless you are wearing heavy insulated leather gloves. Even if the light is turned off it can stay extremely hot for some time.
Movie lights also use a lot of electricity. Working with electricity is always potentially dangerous if you don't know what you are doing and work very carefully.
To use many of the kinds of lights I'll be talking about requires a special portable generator that you will need to rent. The typical household wiring can't begin to handle large movie lights. A 1K lamp draws about 10 amps of electricity. That as half as much electricity as a single circuit in modern houses is designed to handle. A single 10K spotlight would need all the electricity that the average house has available on all the circuits put together.
Most of the kinds of movies the typical independent filmmaker does will not require anything like this amount of lighting, especially with modern video cameras.
Type of bulbs
Common household tungsten light bulbs can be used to light your film but the color temperature is typically around 2900 degrees K so the light will still look a bit orange compared to a true photo bulb. The slight color cast is often not a problem. With filters or by color balancing your video camera you can adjust the color to look right.
Special photo bulbs that are usually 250 or 500 watts are sold that have correct tungsten color balance. They are inexpensive but have a very short life. After about 25 hours burning time they become badly blackened, lose much of their brightness and should be replaced.
Photo bulb may be either photofloods which are typically used in domed reflector units, or reflector floods which have their own built in reflector.
Tungsten-Halogen bulbs are designed so they don't blacken with age. They also are usually 250 or 500 watts and are very small and rather fragile. A good bounce will usually destroy a burning halogen bulb. They are available up to 20,000 watts. The quartz glass is damaged by oils so you should always wash your hands and/or use a clean rag to touch or change a halogen bulb. Halogens are daylight color balanced.
HMI (Halogen-Metal-Iodide) Bulbs are about four times as efficient in their use of electricity as tungsten-halogen bulbs so they are both brighter and slightly cooler for the same amount of electricity. They have the added bonus of being balanced for daylight (5600 to 6000 degrees K).
They use standard AC current but require a heavy ballast unit to control the lamp. Although they have a very fast flicker it is typically timed to be the same frequency as film and video cameras and is not noticeable. HMI's would be a very good source of light except they are extremely expensive and far beyond the budget of all but the best heeled indie movie makers.
There are two types of Fluorescent bulbs as far as filmmaking is concerned.
Conventional fluorescent lights, as commonly used in public buildings, are terrible as a light source. They cast a flickering, greenish light that makes anyone look terrible. The light they produce does not contain equal amount of all the basic colors so no amount of color correction can make them look natural.
Of course if this is the look you want for you movie then you're all set. Remember that the human eye adjusts to the quality of flourescent lights and film and video cameras don't.
Fluorescents for film and video are available. Kino Flo makes light units for their daylight balanced fluorescent bulbs with special ballasts that make them flicker free. You can also buy Optima 32 bulbs for tungsten balanced lighting, and for daylight balance use the Vita-lite and Chroma50 tubes.
Reflectors are another category of lighting instrument that are priced right for low-budget filmmaking. Use them to fill in shadows as you use the sun other other natural light sources for you key light.
Crumple aluminum foil then straighten it out and paste for tape it onto large sheets of cardboard. Buy foam core boards from art supply stores with white, silver or gold foil coatings. You can also get fold up reflectors that work like the round foldup sun screens people put in their car windows to block the sun, but YIU reflectors work just as well and cost a lot less.
The most contollable lighting units are the focusing spotlights which use a fresnel lens (pronounced fruh-NELL, silent "s"). They emit a bright, focused light in parallel rays that travel over a distance with less fall-off of brightness. They will cover a rather wide area with a 30 degree spread or focus down to as little as a five degree spread.
These are the type of instrument traditionally most used in filmmaking. The units are relatively heavy and expensive and may be out of their league for many low-budget filmmakers.
Open-faced spotlights don't use an expensive fresnel lens. They are able to focus the light beam by using a carefully designed reflector shape and moving the actual light bulb forwards and backwards. They are less expensive than fresnel spots, lighter but don't have the same crisp hard light.
For low-budget filmmaking they are a good choice.
Nonfocusing lights include the lowest cost lights available for filmmakers.
PAR lamps look a bit like automobile headlamps. They have a built-in reflector and come in variety of wattages and coverage angles. Open bowl shaped reflectors are available in many sizes that take standard tungsten or photo tungsten bulbs.
For the very lowest budget you can use clamp-on reflectors from your local hardware store. Also very inexpensive, but very bright, are quartz-halogen work lights from lumber stores.
Umbrellas and softlights give very soft and attractive light. Umbrellas are just umbrellas made with a white or reflective inner surface. Shining any light into them reflects back a very broad, soft coverage. Softlight or softboxes and large cloth boxes on a metal frame with a light source inside. They also give a very broad light.
Barndoors use metal flaps to cut off the light from falling on part of the set.
Scrims are pieces of metal screening that lower the amount of light without changing the angle or color.
Cookies are sheets of material with holes cut out. When placed in front of a light they created a dappled appearance to the set, much like when light filters through tree leaves.
Century stands, or C-stands, are the stands most commonly used in the industry. They are very strong but a bit expensive for low-budget filmmakers.
Sand bags are cloth bags full of sand to weight your light stands so they aren't pushed over by accident. Use Them!
Gels are filters made out of a thin, heat resistant material to alter the color of your light instruments. They are available in a large range of colors and sizes.
Other Lighting Resources
Meadows Farm Studios has a great, detailed article on video lighting.