Why This Matters
Lighting design isn't just about making actors visible—it's about sculpting space, directing attention, and creating emotional landscapes that support the story. Every term in this guide connects to core design principles you'll apply in production work: controllable properties of light, fixture selection, beam manipulation, and cueing systems. Understanding these concepts means you can communicate effectively with your production team and make intentional choices that serve the narrative.
Don't just memorize definitions—know what each term allows you to do. When you understand that intensity and color temperature both affect mood, or that gobos and barn doors both shape light but in fundamentally different ways, you're thinking like a designer. That's the difference between technical knowledge and creative fluency.
Controllable Properties of Light
These are the fundamental qualities you manipulate every time you design. Master these, and you understand what light can do.
Intensity
- Brightness level of a light source—measured in lumens (output) or foot-candles (illumination on a surface)
- Controls mood and focus by drawing the eye to brighter areas and letting others recede
- Adjusted via dimmers to create dynamic shifts during performance
Color
- The hue of emitted light—achieved through gels, LED mixing, or inherent lamp characteristics
- Directly affects emotional tone, with warm colors suggesting intimacy and cool colors creating distance or tension
- Creates visual contrast and depth when multiple colors interact across the stage
Color Temperature
- Measurement of light's warmth or coolness—expressed in Kelvin (K), where lower values (2700K) read warm and higher values (5600K+) read cool
- Critical for consistency when mixing fixture types or matching practicals to stage lighting
- Affects perception of time and place—warm light suggests sunset or candlelight, cool light suggests daylight or sterility
Compare: Color vs. Color Temperature—both affect emotional tone, but color refers to distinct hues (red, blue, amber), while color temperature describes the warmth or coolness of white light along a spectrum. You might use warm color temperature for a "neutral" interior scene, then add a colored gel for a specific dramatic moment.
Focus
- The sharpness or softness of a light beam's edge—adjustable on most theatrical fixtures
- Sharp focus isolates subjects precisely; soft focus blends light for naturalistic washes
- Directs audience attention by controlling where light begins and ends
Beam Characteristics and Control
Understanding how light spreads and how you can shape it determines your ability to place light exactly where you want it—and keep it off everything else.
Beam Angle
- The cone of light where intensity is at 50% or greater—determines the "hot spot" of useful light
- Narrow beam angles (under 20°) create tight pools; wide angles (40°+) cover broad areas
- Drives fixture selection based on throw distance and desired coverage
Field Angle
- The wider cone where intensity drops to 10%—represents visible spill beyond the beam angle
- Critical for planning to avoid unwanted light bleeding onto adjacent areas or scenery
- The difference between beam and field angle tells you how gradual or abrupt the falloff will be
Barn Doors
- Adjustable metal flaps mounted on the front of Fresnel and PAR fixtures
- Control light spread by blocking portions of the beam—top, bottom, left, right independently
- Create rough shaping for washes, though edges remain relatively soft
Shutters
- Internal blades within ellipsoidal fixtures—four shutters that slide into the beam path
- Produce sharp, precise cuts for masking scenery, architecture, or creating geometric shapes
- Essential for accurate control in proscenium and repertory situations where light must stop exactly at a line
Compare: Barn Doors vs. Shutters—both shape light, but barn doors attach externally and create soft-edged cuts, while shutters are internal to ellipsoidals and create razor-sharp lines. Use barn doors for general shaping; use shutters when precision matters.
Color and Pattern Modification
These accessories transform a basic white beam into something with character, texture, and storytelling power.
Gel
- Colored polyester or polycarbonate filter—placed in a gel frame at the fixture's front
- Subtracts wavelengths from white light to produce the desired color, which means gels always reduce intensity
- Available in hundreds of colors from manufacturers like Rosco and Lee, with standardized numbering systems
Gobo
- Metal or glass template inserted into an ellipsoidal's gate—projects patterns, textures, or images
- Creates visual interest by adding breakup (foliage shadows), architectural elements (windows), or abstract texture
- Enhances storytelling by suggesting environment without physical scenery—a window gobo implies a room, leaf breakup implies outdoors
Compare: Gel vs. Gobo—both modify the beam, but gels change color while gobos change shape and pattern. A single ellipsoidal can use both simultaneously: a gobo projecting window panes with a warm amber gel suggesting afternoon sunlight.
Fixture Types and Their Applications
Different instruments produce fundamentally different qualities of light. Choosing the right fixture is half the design.
Fresnel
- Soft-edged wash fixture—named for its stepped lens that produces an even, blendable field
- Adjustable spot-to-flood focus by moving the lamp relative to the lens
- Ideal for washes and blending where you need coverage without hard edges
PAR (Parabolic Aluminized Reflector)
- Punchy, intense beam—originally a sealed-beam lamp, now often LED-based
- Oval beam shape that can be rotated for horizontal or vertical spread
- Excellent for bold color washes and rock-concert aesthetics; less controllable than ellipsoidals
Ellipsoidal (Leko/Source Four)
- The workhorse of theatrical lighting—produces a sharp, controllable beam
- Accepts gobos and has internal shutters for precise shaping
- Available in multiple beam angles (19°, 26°, 36°, 50°) for different throw distances
Compare: Fresnel vs. Ellipsoidal—both are standard theatrical fixtures, but Fresnels produce soft, blendable light ideal for washes, while ellipsoidals produce hard-edged, controllable beams for specials and gobo projection. Most plots use both: Fresnels for general coverage, ellipsoidals for precision.
Lighting Positions and Functions
These terms describe what a light does in your design—its role in the overall composition.
Key Light
- Primary illumination source for a subject—establishes the dominant direction and quality of light
- Sets the mood through its angle, color, and intensity
- Typically the brightest light on a subject, creating the main shadows that define form
Fill Light
- Secondary source that softens key light shadows—placed opposite or at an angle to the key
- Lower intensity than key light to maintain dimensionality while reducing harsh contrast
- Creates balance between dramatic shadow and visibility
Backlight
- Illumination from behind the subject—separates performers from the background
- Creates a rim or halo effect that adds three-dimensionality and visual "pop"
- Essential for depth on stage, where flat front light alone looks lifeless
Wash
- Broad, even coverage of a large area—the foundational layer of most lighting designs
- Created using multiple fixtures (often Fresnels or PARs) blended together
- Establishes base visibility before adding specials and accents
Specials
- Isolated fixtures for specific moments or areas—a solo spotlight, a doorway practical, a moonlight effect
- Draw focus to key dramatic moments or important stage locations
- Planned individually rather than as part of a system, often with unique color or angle
Compare: Wash vs. Specials—washes provide general coverage and establish the overall environment, while specials create specific moments of focus. A scene might play in a cool blue wash until a character's revelation, when a warm special isolates them.
Control Systems and Cueing
This is how you actually run your design—the technology that makes dynamic lighting possible.
Dimmer
- Electronic device controlling power to fixtures—varies voltage to adjust intensity
- Enables smooth fades and transitions rather than abrupt on/off switching
- Rated by wattage capacity—a 2.4kW dimmer can handle fixtures up to 2,400 watts total
DMX
- Digital Multiplex protocol—the industry standard for fixture control since the 1980s
- Sends data over a single cable to address up to 512 channels per universe
- Each fixture receives a unique address allowing individual control from the console
Control Board (Lighting Console)
- The brain of your lighting system—where you program, store, and playback cues
- Ranges from simple preset boards to sophisticated computer-based systems (ETC Eos, grandMA)
- Allows real-time manipulation during tech rehearsals and live adjustment during performance
Cue
- A recorded lighting state or transition—the fundamental unit of a lighting design's execution
- Includes intensity, color, timing, and any other parameter changes for all active fixtures
- Called by the stage manager and executed by the board operator during performance
Compare: Dimmer vs. DMX—dimmers physically control power to fixtures, while DMX is the communication protocol that tells dimmers (and intelligent fixtures) what to do. Your console sends DMX signals; your dimmers receive those signals and adjust power accordingly.
Quick Reference Table
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| Controllable Properties | Intensity, Color, Color Temperature, Focus |
| Beam Characteristics | Beam Angle, Field Angle |
| Beam Shaping Tools | Barn Doors, Shutters, Gobos |
| Color Modification | Gels, Color Temperature |
| Conventional Fixtures | Fresnel, PAR, Ellipsoidal |
| Lighting Positions | Key Light, Fill Light, Backlight |
| Coverage Types | Wash, Specials |
| Control Technology | Dimmer, DMX, Control Board, Cue |
Self-Check Questions
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Both barn doors and shutters shape light beams—what's the key difference in the quality of edge they produce, and which fixture type uses each?
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You're designing a scene set in a forest at midday. Which two tools would you combine to suggest dappled sunlight through leaves, and why?
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Compare beam angle and field angle—if a fixture has a 26° beam angle and a 45° field angle, what does that tell you about its light quality?
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A director asks for the stage to feel "warm and intimate" during a love scene, then "cold and isolating" when the characters argue. Which controllable properties of light would you adjust, and how?
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Explain the relationship between DMX, dimmers, and cues—how do these three elements work together to execute a lighting change during performance?