CTO-009 Color Temperature Orange (Warming) Filter
1/8 CTO colour-conversion filter shifting 5600 K toward 5050 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 5050 K)
- Mired shift: +18 Mired
- Correction strength: 1/8 CTO
- Average transmittance: ~75.2 % T (visible range)
- Peak transmittance: ~91.1 % T near 778 nm
- Minimum transmittance: ~59.7 % T near 447 nm
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Intermediate Mired shifts, combined CTO+diffusion, custom sizes, rapid prototypes
Learn more
CTO-009 delivers a +18 Mired shift to move 5600 K light toward 5050 K. Its smooth spectral slope creates a natural warming effect, with about 75.2 % average visible transmittance and less than 0.3 stops of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Very small colour-temperature trims in broadcast, photography, and other colour-critical lighting setups.
Description
CTO-009 delivers a subtle “kiss-of-warmth” — about an ⅛-CTO shift — perfect for daylight or cool-white LEDs that just need a light amber touch. The spectrum dips to roughly 60 % around 450 nm, then climbs smoothly to ~80 % at 620 nm before leveling just under 90 % beyond 750 nm, lowering CCT by roughly 400–500 K to soften clinical highlights without sacrificing output.
Key advantages
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Light ⅛-CTO shift – Fine-tunes 5600 K sources toward ~5100 K for more natural skin tones and easier mixed-light matching.
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High overall throughput – ≥ 85 % above 665 nm keeps fixtures bright and efficient.
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Neutral spectral roll-off – No green spike; cameras and eyes see a clean, amber-tilted spectrum.
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Glass-hard durability – All-oxide coating shrugs off heat and UV that melt plastic gels.
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Custom sizing – Round, square, or free-form parts from 5 mm to 450 mm, 0.21–3.8 mm thick, on Borofloat®, soda-lime, Schott D263 T, or Corning Eagle XG.
Typical applications
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Broadcast & ENG lighting – Warm key lights just enough to blend with interior practicals.
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Stage front wash – Soften high-power white LEDs while preserving punch and colour-mix headroom.
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Architectural spots – Add a welcoming glow to retail or hospitality spaces without amber overcast.
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Photography fill cards & modifiers – Nudge strobe colour for consistent white-balance in mixed setups.
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Inspection & machine vision – Enhance red-channel contrast where only minimal blue suppression is needed.
Need prototypes next week or high-volume lots next quarter? CTO-009 filters can be coated, diced, and shipped to your exact specifications—fast.
FAQ
CTO-009 FAQ
What is CTO-009 and what is it used for?
CTO-009 is a Quarter CTO for Subtle Warm Integration with Minimal Loss. CTO-009 is a quarter-strength warm-shift filter maintaining transmission above 60 % across the entire visible spectrum, with 83 % red, 76 % yellow, 68 % green, and 90 % NIR. The remarkably gentle profile peaks at 91.1 % overall, ensuring minimal light loss while delivering subtle daylight-to-tungsten color correction. Common uses include Sophisticated Daylight Enhancement, Golden Hour Simulation, Portrait and Beauty Lighting, and High-end Cinematography.
What are the key optical specs of CTO-009?
Key published specs for CTO-009 include Colour shift direction: Warming (5600 K → 5050 K); Mired shift: +18 Mired; Correction strength: 1/8 CTO; Average transmittance: ~75.2 % T (visible range); Peak transmittance: ~91.1 % T near 778 nm.
What applications is CTO-009 best suited for?
CTO-009 is commonly used for Sophisticated Daylight Enhancement, Golden Hour Simulation, Portrait and Beauty Lighting, and High-end Cinematography. Sophisticated Daylight Enhancement - Add subtle warmth to naturally-lit interior and exterior daylight sources without aggressive color correction or aesthetic overtones.
Can CTO-009 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-009 as Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick. Published custom options include Intermediate Mired shifts, combined CTO+diffusion, custom sizes, rapid prototypes. Standard and Custom Formats - Round (5-450mm), square, free-form geometries on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG; 0.21-3.8mm thickness range.
What should I know about angle of incidence and durability for CTO-009?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
