Lighting for film and television

In short

Lighting for film and television is the controlled use of light sources, shaping tools, gels and grip hardware to give an image correct exposure, a chosen colour, modelled form and a mood that matches the story. It is half technical (photometry, colour temperature, electrical load, flicker) and half aesthetic (direction, contrast ratio, continuity between shots). University papers in Production Craft examine it as theory plus a practical lighting-plot submission; placement tests at broadcasters and studios ask it numerically — ratios, exposure, load calculation. Employers that hire for it in India include Prime Focus, Annapurna Studios, Ramoji Film City, Zee, Star/JioStar, Sony, Doordarshan, NFDC, ad production houses, and rental/lighting houses such as Light & Light, Modern Cine Services and Ravi Kiran Cine Lab.

Explained

1. How light is measured — the photometric quantities

• Luminous flux (lumen, lm): total visible light a source emits. Luminous intensity (candela, cd): flux per unit solid angle in one direction — what a spotlight's rating means.
• Illuminance (lux, lx = lm/m²): light *falling on* the subject; this is what an incident meter reads. 1 footcandle = 10.764 lux.
• Luminance (cd/m², "nits"): light *leaving* a surface — what a spot/reflected meter and a waveform monitor respond to; depends on illuminance × reflectance.
• Inverse square law: illuminance falls as 1/d² from a point source. Doubling distance costs two stops. A large soft source close to the subject falls off more slowly than the law predicts over short distances, and only behaves like a point source obeying 1/d² once it is far away relative to its own size.
• Exposure in stops: every doubling of light = 1 stop. Stops between two readings = log₂(ratio).
• Efficacy (lm/W): tungsten ≈ 15-25, fluorescent ≈ 60-90, HMI ≈ 85-105, modern film LED ≈ 70-120. Efficacy decides heat load and generator size.
• Colour temperature (K): the temperature of a black body whose colour matches the source. Tungsten studio lamps 3200 K, household lamps ~2700 K, HMI/daylight 5600 K, overcast sky 6500-7500 K, candle ~1900 K. Low K = warm/orange, high K = cool/blue (opposite of everyday speech).
• Mired (micro reciprocal degree) = 10⁶/K: gels are rated as a *mired shift*, which is additive, unlike Kelvin.
• Colour rendering: CRI (Ra) averages 8 pastel patches — poor at red and at LEDs; TLCI-2012 (EBU) is the television-specific index; TM-30-20 gives Rf (fidelity) and Rg (gamut); SSI compares spectra. Broadcast practice asks for CRI ≥ 90 / TLCI ≥ 85 and matched spectra between fixtures.
• Green-magenta error is measured as CC or duv and corrected with Minus-Green/Plus-Green gel; it is why mixed fluorescent and LED sources look mismatched even at the same Kelvin.

2. Sources and fixtures — classification

• Incandescent/tungsten-halogen: 300 W to 20 kW; 3200 K, CRI ~100, fully dimmable without colour shift beyond warming. Hot, inefficient. Types: Fresnel (stepped lens, spot-flood "spotting" by moving the lamp-reflector), open-face (redhead 800 W, blonde 2 kW), soft light, cyc/ground row, Space Light (hanging silk softbox), Dinky/Baby/Junior/Senior = 200 W/1 kW/2 kW/5 kW.
• HMI (Hydrargyrum Medium-arc Iodide): metal-halide arc, 5600 K, 3-4× the efficacy of tungsten, needs a ballast; magnetic ballasts flicker at 2× mains frequency, electronic ballasts offer flicker-free and "high-speed" modes. 200 W to 18 kW; the standard daylight/window-punch unit in Indian features.
• Fluorescent: Kino Flo-type banks, soft and cool-running, 3200/5600 K tubes, needs high-frequency ballast; largely displaced by LED.
• LED: now dominant. Sub-types — bi-colour (2700-6500 K), RGBW/RGBACL full-colour (gel and gobo emulation, hue/saturation control), hard COB point sources with Fresnel or dome, soft panels, flexible mats, tube lights, cine floodlights. Advantages: battery/DC operation, low heat, DMX/CRMX wireless control, effects engines (fire, TV, police). Limitations: PWM flicker at high camera frame rates, spectral spikes, cheap units with poor Rf and bad skin tones.
• Practicals (lamps in frame) and bounce sources (light thrown onto a white poly/bedsheet/ceiling) are treated as fixtures in a plot.
• Natural light: sun as key, sky as fill; golden hour, magic hour, overcast as a giant softbox. Shaped with reflectors, bounce boards, butterflies/overheads (silk, grid cloth, ND, solid) on frames.
• Modifiers and grip: barndoors, snoot, scrims (single = ½ stop, double = 1 stop), flags/cutters/gobos (cut light), dots and fingers (small cuts), cookie/cucoloris (dappled pattern), soft boxes, chimeras, umbrellas, egg-crate/honeycomb (controls spill of a soft source), C-stand, century stand arm and knuckle, sandbag, apple box, stinger, spigot, menace arm.

3. Gels, diffusion and control of colour and intensity

• Conversion gels: CTB (colour temperature blue) raises Kelvin — Full Blue ≈ −131 mireds, converts 3200 K → ~5500 K at ~35-40% transmission. CTO lowers it — Full CTO ≈ +159 mireds, 6500 K → ~3200 K. Partial grades: ½, ⅓, ¼.
• Correction gels: Minus-Green (magenta) for fluorescent sources; Plus-Green for matching tungsten to fluorescent.
• ND gels: ND0.3 = 1 stop, ND0.6 = 2 stops, ND0.9 = 3 stops — used on windows (often as ND+CTO window rolls) to balance interior to exterior.
• Diffusion: frost, opal, Hampshire, 216 full white (≈1-1.5 stops loss), 250 half, 251 quarter, grid cloth, silk, bleached muslin. Diffusion makes a source bigger relative to the subject — that is what makes it soft; a diffuser far from the subject is still a hard source.
• Dimming: tungsten dims to warmer colour; LED dims without colour shift but may change flicker behaviour; HMI dims only over a narrow range. DMX512 over 5-pin XLR or wireless CRMX, controlled from a lighting console or tablet; channels, patch, cue, blackout, chase are the console terms examined for TV.
• Intensity can be changed five ways: lamp power, distance, scrim, diffusion, dimmer — exam answers are expected to say which to choose and why (distance and scrim keep colour unchanged).

4. Lighting design — direction, ratio and continuity

• Three-point lighting: key (main modelling source, usually 30-45° off the lens axis and above eye line), fill (opposite side, softer, controls shadow depth), back/rim/kicker (separates subject from background). Add background light, eye light, hair light for the classic five-light portrait.
• Quality: hard (small source, crisp shadow edge) vs soft (large source, gradual shadow). Direction: front, 3/4, side (split), back, top, under (horror). Contrast is set by the fill, not the key.
• Lighting ratio = (key + fill)/fill, on the subject: 2:1 = 1 stop (news, comedy, bright TV), 4:1 = 2 stops (standard drama), 8:1 and above = 3+ stops (noir, thriller). Indian television serials typically run flat 2:1 for multi-camera speed and for safe broadcast levels.
• High key (low contrast, bright, even — song sequences, game shows, commercials) vs low key (large dark areas, hard source — thrillers, item-song club looks).
• Motivation and continuity: every light should plausibly come from a window, lamp or sky established in the wide shot; direction, Kelvin and ratio must match across coverage shot hours or days apart — hence lighting continuity stills and meter notes.
• Day-for-night, night-for-night: underexpose and cool the scene, light with hard backlight and keep practicals in frame; avoid lighting the sky.
• Exposure strategy: place the key so the subject's skin sits around middle grey to one stop over; judge with false colour, zebras (70%/100%), histogram and waveform on a calibrated monitor, with an incident meter for ratios and consistency. Log capture widens latitude but does not remove the need to light.

5. Studio and television lighting

• Multi-camera studio: lights hung on a grid/pantographs/barrel and hook clamps, plotted so every camera angle is covered without boom or stand shadows; a lighting plot (scaled plan with fixture symbols, channel numbers and focus notes) plus a cue sheet is the standard deliverable.
• News set: soft key banks, eye light, back light, separate cyc/background wash with colour, plus dedicated desk and chroma-key lighting; levels kept even so auto-iris and switcher do not hunt.
• Chroma key (green/blue screen): light the screen separately and evenly — within ⅓ stop across its area — then light the subject with enough separation and backlight to avoid spill; keep the subject 2-3 m from the screen; use Minus-Green or blue backlight to kill green spill. Blue screen for blonde hair/skin tones, green for better camera sensitivity and lower light levels.
• Exposure vs screen: common practice is the screen at the same exposure as the subject's key or up to ½ stop under for digital keyers.
• Flicker and frame rate: Indian mains is 230 V, 50 Hz; magnetic-ballast HMIs and discharge lamps pulse at 100 Hz. Safe combinations at 50 Hz are 25 fps with a 180° shutter (1/50 s) or 1/100 s; 24 fps needs a 172.8° shutter (= 1/50 s). Indian broadcast is 25 fps (PAL heritage); theatrical shooting is usually 24 fps — the conversion is a standard exam point. High-speed and LED PWM flicker are checked on a monitor at speed before the take.
• Monitor/LED-wall shoots: screen refresh must be in sync with camera; moiré and banding are lighting-department problems in virtual production (ICVFX), where the LED volume becomes the key light.

6. Power, safety and Indian codes

• Supply: 230 V single phase / 400 V three phase, 50 Hz. A 1 kW tungsten lamp draws about 4.35 A at 230 V, so a 16 A domestic circuit safely carries roughly 3 kW.
• Three-phase balancing: distribute the load across R, Y, B within about 10%; never exceed the DG set rating — generator sizing uses kVA = kW/power factor, and inductive ballast loads are rated in kVA with pf typically 0.85-0.95 (electronic ballasts) and much worse for old magnetic ones.
• Compulsory practice: proper earthing (code of practice for earthing, IS 3043), 30 mA RCD/ELCB on portable circuits, correctly derated flexible cables, no joints on the floor run, cable ramps and taping, safety bond/wire on every hung fixture and every barndoor, lamp changes with gloves on cold lamps, UV-blocking glass intact on HMIs (bare arc = skin and eye burns), no water near live gear in rain sequences, fire extinguisher at the dimmer/DB.
• Statutory framework (current): the Electricity Act, 2003 and the CEA (Measures relating to Safety and Electric Supply) Regulations, 2023 (which superseded the 2010 Regulations) govern installation and temporary supply; the National Building Code of India 2016 covers studio electrical and fire provisions and means of escape; the Occupational Safety, Health and Working Conditions Code, 2020, in force from 21 November 2025, is the operative worker-safety law — it defines the audio-visual worker, covers working hours, welfare and accident reporting, and replaced the earlier Factories Act, 1948 and the former Cine-Workers and Cinema Theatre Workers (Regulation of Employment) Act, 1981. Shooting permissions, fire NOC and generator/noise consent come from state film cells or single-window portals and from the state pollution control board; requirements differ by state, so confirm locally.
• Interior illuminance recommendations for the *working* areas of a studio (corridors, workshops, control rooms) follow the Indian code of practice for interior illumination — not the picture levels, which are chosen for exposure, not for comfort.

7. A working method, step by step

1. Read the script and break the scene down: time of day, source of light, mood, moves.
2. Recce the location; note window direction, ceiling height, existing practicals, available power and where the DG can stand.
3. Decide the key's source and direction, then the ratio, then the background; draw the lighting plot with fixture symbols and channel numbers.
4. Build the equipment list (fixtures, stands, grip, gels, cable, distro) and the crew list — gaffer, best boy, lighting technicians, grips.
5. Rig, light the wide master first, then refine for close-ups ("lighting for the close-up, cheating for the wide").
6. Meter: incident reading at the subject for key and fill; check skin on false colour/waveform; shoot a grey card and colour chart for the colourist.
7. Run flicker and shutter checks, note continuity stills and meter values, then de-rig safely and account for gear.

Key points

• Illuminance - lux falling on the subject, read by an incident meter; luminance - light leaving a surface, read by a spot meter.
• Inverse square law - E ∝ 1/d²; doubling the lamp distance loses 2 stops.
• One stop - a doubling or halving of light; stops = log₂ of the ratio.
• Colour temperature - tungsten 3200 K, daylight/HMI 5600 K; lower K is warmer.
• Mired - 10⁶/K; gel shifts add, Kelvin values do not.
• CTB - raises colour temperature (Full ≈ −131 mired); CTO lowers it (Full ≈ +159 mired).
• ND gel - 0.3/0.6/0.9 = 1/2/3 stops, used to balance windows.
• Scrims - single ≈ ½ stop, double ≈ 1 stop, with no colour change.
• Softness - a function of source size relative to the subject and of distance, not of wattage.
• Three-point lighting - key for modelling, fill for contrast, back light for separation.
• Lighting ratio - (key + fill)/fill; 2:1 flat TV, 4:1 drama, 8:1+ low key.
• High key / low key - low-contrast bright look vs large shadow areas with hard light.
• HMI - daylight arc lamp needing a ballast; 3-4× tungsten efficacy; flicker-free only on electronic ballast.
• LED advantages - low heat, DC/battery, DMX control, full-colour; risk is poor spectrum and PWM flicker.
• Flicker rule - at 50 Hz mains use 25 fps/180° (1/50 s) or 24 fps with a 172.8° shutter.
• Chroma key - screen lit separately and evenly within about ⅓ stop; subject 2-3 m clear to avoid spill.
• Power - 1 kW at 230 V ≈ 4.35 A; kVA = kW/pf; balance three phases.
• Statutory - Electricity Act 2003 with the CEA Safety Regulations 2023, NBC 2016, and the OSH&WC Code 2020 (from 21 Nov 2025) covering audio-visual workers.

Formulas and examples

Example 1 - inverse square law. A 2 kW Fresnel gives 800 lux on an actor at 3 m. The actor is moved to 6 m.

• E₂ = 800 × (3/6)² = 800 × 0.25 = 200 lux, i.e. 2 stops down (log₂(800/200) = 2).
• To restore 800 lux at 6 m you need 4× the intensity — a 8 kW unit, or four 2 kW units, or move the lamp back to 3 m.

Example 2 - lux to f-stop. Incident reading 500 lux, ISO 800, 24 fps with a 172.8° shutter.

• t = 172.8/(360 × 24) = 172.8/8640 = 1/50 s.
• N² = (500 × 800 × 0.02)/250 = 8000/250 = 32 → N = 5.66 → set f/5.6 (√32 = 5.657, so this is f/5.6 almost exactly).
• If the DOP wants f/8 (N² = 64), required E = 64 × 250/(800 × 0.02) = 16000/16 = 1000 lux — exactly one stop more light.

Example 3 - lighting ratio. Key meters 400 lux on the lit side; fill meters 100 lux on the shadow side.

• Lit side receives key + fill = 500 lux; shadow side = 100 lux → ratio = 500/100 = 5:1.
• In stops: log₂5 = 2.32 stops — a drama look. To get a flat 2:1, raise fill to 500 lux (lit side then 900/500 = 1.8:1) or scrim the key: key 100 lux + fill 100 lux on the lit side = 200/100 = 2:1.

Example 4 - gel and colour temperature. A 2 kW tungsten unit (3200 K) must match an HMI at 5600 K.

• Required shift = 10⁶/5600 − 10⁶/3200 = 178.6 − 312.5 = −133.9 mireds → Full CTB (≈ −131 mireds) is the correct gel.
• Full CTB transmits about 36%, a loss of log₂(1/0.36) ≈ 1.47 stops, so the gelled 2 kW now behaves like roughly a 720 W unit. The cheaper route is to use a 5600 K LED or an HMI and keep the stop.

Example 5 - electrical load. Five 1 kW tungsten lamps plus two 1.2 kW HMIs (pf 0.9) on one 230 V board.

• Tungsten current = 5000/230 = 21.7 A — already beyond a 16 A circuit, so split across two circuits (3 + 2 lamps = 13.0 A and 8.7 A).
• HMI apparent power = 2 × 1.2/0.9 = 2.67 kVA → current = 2670/230 = 11.6 A.
• Total real load ≈ 5 + 2.4 = 7.4 kW; at pf 0.95 overall the generator must supply ≈ 7.4/0.95 = 7.8 kVA, so a 10 kVA set (with ~25% headroom for starting surge) is the right hire.

Where it is used

• Feature films and web series: gaffer, best boy, lighting technician and grip roles on sets in Mumbai, Hyderabad (Ramoji Film City, Annapurna Studios), Chennai (EVP, AVM), Kochi and Noida/Film City.
• Television studios and news: lighting director and console operator on multi-camera floors at Doordarshan, Star/JioStar, Zee, Sony, Aaj Tak, Asianet; grid rigging, chroma sets and cyc washes.
• Advertising, product and tabletop: precise soft-box and polariser work for FMCG, jewellery and automotive commercials; still-life studios in Mumbai and Delhi.
• Events, live broadcast and OTT shoots: DMX-controlled LED rigs for award shows, IPL studio sets and concert television, where the same fixture serves stage and camera.
• Rental and technical supply: lighting houses that spec, maintain and deliver HMI/LED packages and generators; roles in equipment testing, DMX networking and electrical safety compliance.
• Virtual production and VFX pipelines: lighting for LED volumes and for clean plates, plus HDRI capture and on-set lighting reference balls so CG matches the practical light.

Interview questions

• Q: What makes a light soft rather than hard? A: The apparent size of the source relative to the subject — a big source close in gives soft, wrapping shadows; the same source far away is effectively small and hard. Wattage is irrelevant to softness.
• Q: State the inverse square law and give its practical use. A: E = I/d², so illuminance falls with the square of distance; moving a lamp from 2 m to 4 m loses two stops, which is how you set fill levels or fall-off on a background without touching the dimmer.
• Q: What is a lighting ratio and what value would you use for a TV serial? A: (Key + fill)/fill measured at the subject; about 2:1 (one stop) for a bright, flat, multi-camera serial, against 4:1 for drama.
• Q: How do you convert a tungsten lamp to daylight and what does it cost you? A: Full CTB gel, a shift of about −131 mireds from 3200 K to around 5500 K, at a loss of roughly 1.5 stops.
• Q: Why does an HMI sometimes flicker on camera and how do you avoid it? A: A magnetic ballast pulses at twice the 50 Hz mains, i.e. 100 Hz; use an electronic flicker-free ballast, or shoot 25 fps at 1/50 s, or use a 172.8° shutter at 24 fps.
• Q: How do you light a green screen? A: Light the screen separately and evenly within about a third of a stop, keep the subject 2-3 m away, backlight the subject to break any spill, and match the screen exposure to the subject's key or up to half a stop under.
• Q: Difference between an incident and a reflected meter reading. A: An incident meter at the subject measures the light falling on it and is independent of subject tone — best for ratios; a spot meter reads luminance from a surface and tells you how a specific tone will render.
• Q: You have one lamp and an interview to light. What do you do? A: Place it as a 3/4 soft key, bounce or reflect a bit of its spill back as fill from the opposite side, and use the background's own light or a practical for separation.
• Q: CRI 95 LED still gives bad skin tones. Why? A: CRI averages pastel patches and hides spectral spikes and poor deep-red rendering; check TLCI, TM-30 Rf/Rg or SSI, and always test the fixture against a colour chart on the shooting camera.
• Q: Why do you light the close-up before the wide? A: The close-up is where the audience judges skin, eyes and mood; the wide can be cheated with flags, hidden units and continuity-matched direction, whereas a compromised close-up cannot be fixed.
• Q: How much current does a 2 kW lamp draw and what cable and protection do you use? A: About 8.7 A at 230 V, so not more than one such lamp on a 16 A circuit with the rest of the load counted; use correctly derated flexible cable, earthed connectors and a 30 mA RCD, with the fixture safety-bonded.
• Q: Which law now governs working hours and safety for lighting crew in India? A: The Occupational Safety, Health and Working Conditions Code, 2020, in force from 21 November 2025, which covers audio-visual workers and replaced the earlier Factories Act and the former Cine-Workers and Cinema Theatre Workers (Regulation of Employment) Act, 1981.

Common mistakes

• Thinking higher Kelvin means warmer light, or adding Kelvin values instead of mired shifts when stacking gels.
• Assuming diffusion alone makes light soft while leaving the diffuser pressed against the lamp far from the subject.
• Quoting a lighting ratio as key:fill measured in isolation instead of (key + fill) on the lit side against the shadow side.
• Forgetting gel, scrim and diffusion transmission losses when calculating the stop, then under-exposing the take.
• Shooting 24 fps at a 180° shutter under 50 Hz discharge or cheap LED sources and discovering flicker in the edit.
• Loading a single 16 A circuit or an undersized DG set with the full lighting package, and leaving phases unbalanced.
• Ignoring continuity — changing key direction, Kelvin or ratio between master and coverage, which makes the scene uncuttable.

Related topics

Cinematography: camera, lenses and shot design · Colour grading and DI workflow · Production design and art direction · Studio engineering and multi-camera television production · Visual effects and chroma key compositing · Set electrical safety and power distribution