The following is a glossary of lighting terms from Ross Lowell's book, Matters of Light & Depth.
* Not a conventional term but coined by Ross Lowel. Words with Initial Caps are separate entries elsewhere in the glossary.
Absorption of Light
The fate of non-Reflected, non-Scattered light. The reason why black suits are difficult to light (and hot to wear) is that they absorb most of the light and convert it into heat. Surfaces that absorb only parts of the Spectrum appear pink, purple, green, or some other color.
Any Source from almost any direction which is used in addition to more basic lights to call attention to an object or area - not the Lighting.
A subject, scene, or image without color.
Aims of Lighting
To enhance mood, atmosphere, and drama; to illuminate the story; to separate planes; to suggest depth; to direct attention; to reveal character; to convey time of day; to enrich and, occasionally, bedazzle. Minimum aim: to stimulate microchips and silver halides.
Formula: Amps = watts ÷ volts. Tip: When the no-nonsense electrician asks: "How many amps will you need at 120 volts?" just divide the maximum watts you expect to use by 100 (it has a built-in safety factor and you won't have to hunt for a pencil). Need 3,000 watts? 3,000 ÷ 100 = 30 amps. Remember, if you don't know watts what, you'll blow it - with the electrician.
Angle of Light
The angle formed between the light/subject axis and camera/subject axis is probably the most important aspect of light in determining mood, modeling, and "message." Both the horizontal and the vertical angle should be indicated. Examples: true Rim Light 180 degrees for both; Key Light commonly 15 to 45 degrees for both. Tip: On the job, pros tend to use less specific designations such as Top, Side, and 3/4-back, which indicate the approximate angle yet allow for fine-tuning based on the subject.
Angle of Reflection
see Glare Angle
Angle of View
The angle accepted by a lens or meter which depends upon its Focal Length and the camera Aperture (commonly, the horizontal angle). Answer Print, Trial Print (film) One of the early lab attempts (typically there are two or three) to combine picture and sound. It is also the time for light and color correction and exploration; the time when all your previous efforts can be spoiled or perfected. Be there. See: Timed Print (an earlier stage).
Aperture (light and camera)
The camera, projector, or printer opening that controls the size and proportions of the recorded image - the Frame. See: Aspect Ratio. The area from which light is emitted from a Fixture is also an aperture and the size, among other factors, influences the Quality of the light.
A rectangular wooden box used to support people, props, or equipment at any of three different heights. Thinner half-apples offer other options, alone and in stacked combinations.
A very large, near-daylight, carbon-arc source that was used to shoot Hollywood blockbusters - now rivaled by HMI and MSR Lights.
An ambiguous term that refers to light produced by electricity as opposed to a Natural source and to illumination introduced to record images. Depending upon how it is used, it looks either artificial or natural.
Aspect Ratio, Frame Proportions
The proportions of an Image; width divided by height. Example: 1:1.33 for 16mm. The ratio changes depending upon the medium of reproduction and the proportions of the monitor or screen on which they are projected, which plays havoc with Composition and the tops of heads. Tip: Foreground framing with dark shapes will appear to change the aspect ratio.
A continuously graduated color or Neutral-Density camera filter used to tame snow, enrich sunsets, and perform Absorption magic more subtly than can be done with a Graduated Filter.
Attributes of Light
Every source has five main attributes that affect the quality of light emitted and the overall lighting-look: 1) Hard or Soft (or in between); 2) Intensity (the amount of light); 3) Direction (in relation to the lens/subject axis); 4) Color (of light emitted); and 5) Beam pattern (the Beam Angle, shape, and any shadow patterns). All but color are affected by the light's Size and Distance, which may also be considered attributes.
Auto White Balance
Some video cameras automatically adjust the relative proportion of red, blue, and green in order to neutralize color variations from one light source to another. See: White Balance for more colorful details.
Automatic exposure controls on video cameras, for all their blessings, are subject to rapid, distracting brightness changes. Alternative: use it to set exposure, lock it out and make manual Stop changes, or allow the image temporarily to be dark or light. See: Through-the-Lens Metering.
Light of almost any sort which exists and has not been introduced to record images. Its use is sometimes fast, cheap, and even beautiful. Tip: The more you understand lighting technique, the better prepared you will be to take advantage of the good stuff - when it is available. Before committing, what are the odds that it will last as long as your shooting will and that the mood is appropriate? Keep a few lights available - in case. Also see: Natural Light.
Available Light Phobia *
The morbid fear of uncontrolled lighting situations.
The light meter's arithmetic mean of all the light it "gathers."
Axial or Axis Lighting
Illumination from the lens axis using light reflected from a partially mirrored glass angled 45 degrees in front of the lens. Used primarily for medical and scientific recording where access or shadows are a problem. Also see: Ring Flash.