Executive Summary
Film & TV lighting is rapidly evolving from "RGB + dual-white (RGBWW)" toward multi-color LED engines. Six-color engines such as the RGBLAC (Red · Green · Blue · Lime · Amber · Cyan) found in the Nanlite Forza 60C and Nanlux Evoke 900C already reach a Color Rendering Index (CRI) of 96, Television Lighting Consistency Index (TLCI) of 95, TM-30 fidelity Rf 94 / gamut Rg 100, and a CCT range of 1800K–20000K. This white paper proposes adding two dedicated channels — 450 nm (UV-cut) and Deep Red 660 nm — to form an 8-channel spectral engine that closes the gaps at the violet-blue and deep-red ends of the spectrum, thereby:
8-ch
Primary channels (RGBLAC + 450nm(UV-cut) + DeepRed660)
≈158%
Relative sRGB gamut coverage (estimate)
≤40 kHz
Flicker-free PWM, compatible with high-speed capture
1800–20000K
Wide continuous CCT + G/M ±100
This white paper surveys the most advanced light-source technologies in the film & TV industry, justifies the physiological and colorimetric basis for deep-red / violet-blue extension, and provides engineering guidance on SPD design, driving, thermal management, control and calibration — accompanied by an SPD spectrum chart, a CIE 1931 gamut diagram, a system architecture diagram and a benchmark comparison chart.
Conclusion first: simply adding channels does not automatically improve quality — what matters is whether each channel's peak wavelength and half-width (σ) fall where both the eye and the camera are sensitive and the spectrum stays continuous. 450 nm (UV-cut) and Deep Red 660 nm precisely fill the two weakest bands of RGBLAC, 400–460 nm and 620–680 nm.
Contents
1. Industry Requirements & Technology Trends
Film & TV lighting demands far more from a light source than general illumination. Core metrics include:
- Color fidelity: CRI ≥ 95, TLCI ≥ 95; professional grades require TM-30 Rf ≥ 94 and Rg near 100;
- Spectral Similarity Index (SSI): the closer a source's SPD matches a reference (e.g. daylight D56, tungsten), the more naturally multiple fixtures mix and match real-world light;
- Adjustable CCT & Green/Magenta (G/M): continuous 1800K–20000K, with G/M shift ±100 to match the environment;
- Flicker-free: PWM frequency in the tens of kHz, compatible with high-speed shutters and slow motion (e.g. 40 kHz class);
- High optical density & uniformity: COB delivers an area-light quality, avoiding pixelation and moiré;
- Silent & lightweight: active-cooling fans ≤ 25 dB(A), with battery-powered portability.
Studios such as Netflix have already written TLCI > 90 and SSI into their procurement specs; virtual production (Virtual Production / ICVFX) LED walls demand 110% NTSC / DCI-P3 gamut, 16–22-bit gradation and ≥ 3840 Hz refresh. The industry consensus has shifted from "bright enough" to "correct spectrum, accurate color, matchable light."
2. Cutting-Edge LED Light-Source Technologies
2.1 COB & CSP High-Density Integrated Packaging
Chip-on-Board (COB) bonds hundreds of micro-LEDs directly onto a high-thermal-conductivity substrate (aluminum boards at 2–4 W/m·K, far above FR4's 0.5–1), eliminating pixel gaps to form a continuous, uniform area light. Independent measurements show 20–30% higher brightness at equal power, efficacy up to 150 lm/W, and > 95% power utilization. Chip-Scale Package (CSP) goes further, removing the lead frame and bond wires so a single COB can integrate 256 independently controlled light units (e.g. Surestar's SPRL technology), achieving spot uniformity ≥ 90% and color difference ΔE ≤ 1.5.
Film/TV fixtures (Aputure Nova P600c, Nanlux Evoke 900C) widely adopt rigid COB arrays plus a mixing chamber, balancing high optical density with spectral uniformity.
2.2 Full-Spectrum Phosphors & "Violet Pump + Broadband Phosphor"
Moving beyond the narrow spectrum of the traditional blue pump (450 nm) + yellow-green phosphor, the state of the art uses a violet/near-violet pump (400–420 nm) to excite broadband phosphors covering a more continuous 440–700 nm spectrum, fundamentally reducing CRI defects (especially R9 deep-red and R12 blue). Bridgelux's Thrive™ full-spectrum platform is one such example. For a color-mixing engine, this explains why adding Lime/Amber/Cyan beyond RGB markedly improves mid-tones and naturalness.
2.3 Multi-Color Mixing (RGB → RGBW → RGBWW → RGBLAC)
Increasing the channel count directly expands the mixable gamut and the shaping freedom of the white-light spectrum:
| Engine | Primaries | Typical CRI / TLCI | Strength / Limitation |
| RGB | Red · Green · Blue | ~85 / ~88 | Vivid colors, but tinted white and poor skin tones |
| RGBWW | RGB + warm / cool white | ~95 / ~94 | Natural white, but limited saturated-color gamut |
| RGBLAC | RGB + Lime + Amber + Cyan | 96 / 95 (Rf 94, Rg 100) | Wide gamut, good skin tones, refined low-saturation tones |
| RGBLAC+ID+DR | Above + 450nm(UV-cut) + DeepRed660 | ~97 / ~96 (est.) | Fills violet-blue & deep-red continuum; highest red saturation |
2.4 Flicker-Free Driving & High-Frame-Rate Compatibility
LED dimming relies on PWM; to remove banding and flicker under high-speed capture, professional drivers push PWM to 1,282–40,000 Hz (e.g. PROLIGHTS EclFresnel, Exalux LEDMaster, RC4 LumenDim series). Key design points:
- Independent constant-current source per channel + phase-shift to reduce ripple;
- Multi-range PWM (615 Hz flicker-free / 5 kHz artifact-free video / 20 kHz silent / 40 kHz ultra-slow-motion);
- 0.1% steps, logarithmic / ISL dimming curves for smooth, stepless transitions.
2.5 Wireless Control: LumenRadio CRMX / DMX / RDM / Art-Net
Film sets widely use LumenRadio CRMX wireless DMX/RDM (2.4 GHz, 300 m range), alongside wired DMX512, RDM E1.20 and Art-Net / sACN over Ethernet. The Nanlux Evoke 900C already integrates Art-Net/sACN and can talk directly to Unreal Engine to react in real time to virtual environments; apps such as Sidus Link and NANLINK provide lightweight Bluetooth / 2.4G control.
2.6 Thermal Management & Silence
High-power COB junction temperature must be kept below 90°C to curb lumen depreciation. The cutting edge uses copper heat pipes + vapor chambers + smart variable-speed fans to hold ~22–25 dB(A) at 35°C ambient; some models offer a fan-off mode (reduced power). Longer infrared wavelengths carry higher thermal load, so the Deep Red 660 channel needs its own thermal budget.
2.7 Virtual-Production LED Walls (COB)
XR / ICVFX replaces green screens with COB LED walls: the surface light is inherently diffuse, eliminating moiré; contrast reaches 10,000:1, gradation 16–22 bit, refresh ≥ 3840 Hz, and gamut 110% NTSC / DCI-P3.
3. The RGBLAC Color Engine Explained
Beyond conventional RGB, RGBLAC adds three complementary primaries so it can more precisely approach the black-body locus and natural daylight, and extend saturated colors:
| Channel | Center wavelength | Role |
| Red (R) | ~620 nm | Red body; drives warm tone and skin ruddiness |
| Green (G) | ~525 nm | Main contributor to brightness; sets lumens and skin green balance |
| Blue (B) | ~455 nm | Blue tone and cool-white base |
| Lime (L) | ~565 nm | Fills green–yellow gap; boosts lumens and mid-tones |
| Amber (A) | ~595 nm | Supplements red–orange band; enables true G/M adjustment along the isotherm |
| Cyan (C) | ~498 nm | Fills cyan–green gap; boosts cyan-blue saturation and oxygenated-hemoglobin skin rendering |
Because of Amber, the red–green balance is adjusted based on Δuv (coordinates always move along the Planckian isotherm) rather than simply adding/removing R/G, giving more natural skin tones. The Forza 60C measures CRI 96, TLCI 95, TM-30 Rf 94, Rg 100.
4. Extending with 450 nm (UV-cut) + Deep Red 660 nm
RGBLAC still has spectral gaps at both ends: the 400–460 nm band rests on a single Blue peak, and the deep-red 620–680 nm band on a single Red peak. Adding two dedicated channels closes the loop:
4.1 450 nm (UV-cut) — Violet-Blue Extension
- Skin safety: The NANLUX Nebula C8 — the industry's first commercially shipping 8-color engine (RGBLAC + Indigo + Deep Red, launched 2025, used in the Evoke 600C / 150C) — already employs an Indigo LED to improve skin rendering and is engineered with UV-cut to strip out sub-400 nm radiation, avoiding skin/eye UV hazards for cast and crew. This is now a hard requirement for film lighting.
- Colorimetry: 450 nm sits in the high-sensitivity violet-blue region, completing RGBLAC's 430–470 nm continuum so violet-blue tones like sapphire, indigo, night sky and silk highlights gain markedly in saturation, and SSI (D56) rises.
- Human factors: an appropriate cyan-blue (480 nm) share tunes circadian parameters (m-EDI / M-P ratio), supporting human-centric lighting scenarios.
4.2 Deep Red 660 nm (Deep-Red Extension)
- Hemoglobin absorption peak: 660 nm is near the maximum absorption of heme a and is a cellular resonance frequency (mid 600–720 nm band), significantly enhancing the "ruddy realism" of skin and blood-related materials — an invisible bonus for on-camera skin.
- Red saturation: adding 660 nm beyond the 620 nm red peak means extreme saturated reds — crimson, wine, sunset, flame — no longer look "dark and burnt", with big gains in R9/R12.
- Thermal budget: deep-red LEDs have slightly lower external quantum efficiency and run hotter, requiring separate constant-current and thermal accounting (see §7.3).
Physiological basis: skin reflectance is most sensitive to mixed light at two windows — cyan-blue (~490 nm, oxygenated hemoglobin) and deep red (~660 nm, heme/tissue). RGBLAC already includes Cyan (498); adding DeepRed (660) completes the "skin-tone dual window" coverage — the core mechanism by which this scheme improves skin fidelity.
5. Color Science Fundamentals
- CIE 1931 xy: chromaticity described by x, y (Y normalized); a mixed-color result falls inside the convex hull formed by the primaries. Primaries closer to the spectral locus reproduce purer saturated colors.
- Spectral Power Distribution (SPD): a luminaire's true "ID card". Both camera and eye respond to SPD, not just CIE xy; SSI measures how similar two sources' SPDs are.
- CRI / TLCI: average color-rendering deviation from a reference; TLCI is specific to camera response. Both often blind to saturated colors and deep red.
- TM-30 (IES): uses 99 color samples to give fidelity Rf and gamut Rg (100 = identical to reference), more comprehensive.
- SSI (Spectral Similarity Index, 0–100): per-wavelength correlation with a reference source's SPD; higher means easier mixing and matching real-world light.
- G/M (Green–Magenta) balance: fine-tuned along the isotherm to remove "green/magenta cast", controlled by Δuv.
6. 8-Channel System Reference Architecture
7. Engineering Guidance
7.1 SPD (Spectrum) Design Criteria
- Model each channel with a Gaussian
g(λ)=h·exp(-(λ-c)²/(2σ²)); recommended center wavelengths and half-widths: Indigo 450/σ14, Blue 455/σ15, Cyan 498/σ16, Green 525/σ15, Lime 565/σ26, Amber 595/σ20, Red 620/σ13, DeepRed 660/σ18.
- White synthesis: under the CCT target, make the envelope hug the black-body / daylight SPD to raise SSI.
- Indigo channel must strip < 400 nm (UV-cut phosphor/package) to protect eyes and skin.
- Use a wide Lime half-width (σ≈26) to raise lumens and mid-tones, avoiding "sacrificing brightness for gamut".
7.2 Driving & Control
- 8 independent constant-current sources, 16-bit (65,536-step) dimming resolution; PWM default ≥ 40 kHz for high-speed capture.
- Phase-shift reduces bus ripple; supports logarithmic / inverse-square (ISL) dimming curves.
- Control protocols: DMX512 + RDM (addressing/config) + LumenRadio CRMX (wireless) + Art-Net/sACN (virtual production).
- Per-channel minimum step 0.1%, G/M ±100, continuous CCT 1800–20000K.
7.3 Thermal & Structure
- COB mounted directly on copper substrate (2–4 W/m·K); heat pipe + vapor chamber keep junction temp below 90°C.
- DeepRed 660 and Indigo 450 get separate thermal budgets (deep red has lower EQE and runs hot), with margin reserved.
- Smart fan ≤ 25 dB(A); offer a "silent / fan-off" reduced-power mode for dialogue recording.
7.4 Calibration & Quality Control
- Per unit, factory SPD trim with a spectroradiometer (e.g. X-Rite / Konica Minolta), locking targets TM-30 Rf ≥ 94, Rg 100±3, SSI(D56) ≥ 78; batch consistency ΔE ≤ 1.5.
8. Application Scenarios
Portrait
Cyan+DeepRed skin dual-window, Amber ruddiness, Indigo lifts violet-blue highlights
Product
Metal/jewelry highlight rendering; RGBLAC wide gamut avoids color cast
VP/XR
Spectrum match with LED wall (SSI); Art-Net real-time link to Unreal
Ambience
HSI/XY/Gel modes, 15+ built-in effects; sunset/neon stay saturated, not burnt
9. Benchmarks & Validation
The chart below compares the three engine classes on color rendition and gamut (values are typical industry figures and this scheme's design targets — illustrative benchmarks; deployment should follow measured SPD).
10. Implementation Roadmap & Best Practices
- Initiation: define target luminaire form (point / area / LED wall), power tier (60 W / 600 W / 900 W+), CCT range and gamut goal.
- Engine selection: adopt an 8-channel COB/CSP array; confirm Indigo channel UV-cut compliance (IEC/EN 62471 photobiological safety).
- SPD simulation: iterate Gaussian-model parameters, simulate SSI, TM-30, CRI; lock the ratio once targets are met.
- Driver & thermal design: 8-channel constant current + 40 kHz PWM + heat-pipe cooling; prototype and run thermal-rise tests.
- Control integration: DMX/RDM + CRMX + Art-Net firmware; co-test with app (NANLINK/Sidus class).
- Calibrated mass production: per-unit spectro trim, write per-unit SPD compensation coefficients; factory report includes CRI/TLCI/TM-30/SSI.
- Field validation: SSI comparison against daylight/tungsten reference lamps; flicker-free acceptance under high-speed capture.
Best-practice tips: ① Don't sacrifice per-channel brightness and cooling just to add channels; ② Indigo must be UV-cut, eliminating sub-400 nm radiation; ③ DeepRed needs a separate thermal budget; ④ Accept cross-fixture consistency by SSI, not just CIE xy; ⑤ Keep a spectro archive per batch for later color management (ACES/IDT).
Key Terms
RGBLAC450 nm (UV-cut)Deep Red 660 nmCOB / CSP
Full-Spectrum PhosphorFlicker-Free PWMCRMX / DMX / RDM
TM-30 (Rf / Rg)SSITLCIG/M Balance
Virtual ProductionSPDCIE 1931 xy