CTO-015 Color Temperature Orange (Warming) Filter
1/2 CTO colour-conversion filter shifting 5600 K toward 3800 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Warming (5600 K → 3800 K)
- Mired shift: +67 Mired
- Correction strength: 1/2 CTO
- Average transmittance: ~55.2 % T (visible range)
- Peak transmittance: ~95.3 % T near 728 nm
- Minimum transmittance: ~15.4 % T near 381 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-015 delivers a +67 Mired shift to move 5600 K light toward 3800 K. Its smooth spectral slope creates a natural warming effect, with about 55.2 % average visible transmittance and approximately 0.7 stops of light loss.
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Moderate warming when daylight and tungsten need to blend, especially for interview lighting, event rigs, and warmer skin tones.
Description
CTO-015 pushes daylight and cool-white LED sources firmly into the tungsten arena. Transmission stays below 25 % until roughly 540 nm, then climbs rapidly, breaking past 90 % by 630 nm and holding a flat 92 – 95 % all the way to 780 nm. The steep roll-on produces a strong amber hue—about a ¾-CTO correction—giving fixtures a rich, incandescent character while maximising red output and avoiding the heat-sag that plagues plastic gels.
Key advantages
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¾-CTO warmth – Shifts 5600 K daylight toward ~3000 K for seamless tungsten matching.
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High red efficiency – > 90 % T from 630 – 780 nm keeps lumen output high and skin-tones vibrant.
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Robust blue suppression – < 25 % T below 540 nm eliminates harsh blue glare from LED or HMI sources.
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All-glass durability – Hard oxide coatings resist heat, UV and abrasion far longer than polyester or polycarbonate gels.
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Custom sizing – Round, square or free-form blanks from 5 mm to 450 mm, 0.21 – 3.8 mm thick, on Borofloat®, soda-lime, D263 T or Corning Eagle XG glass.
Typical applications
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Film & TV lighting – Warm daylight panels or HMIs without stacking multiple gels.
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Stage & live events – Create cosy amber washes and key lights that stay bright show after show.
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Architectural accenting – Add inviting warmth to lobbies, restaurants and retail while blocking blue that can fade fabrics.
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Photography strobes – Give speed-lights or monolights a golden-hour tint for portrait and product work.
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Machine-vision – Boost red-channel contrast for inspections where blue light obscures defects.
Need a prototype in days or a production run next quarter? CTO-015 filters can be coated, diced and delivered to your exact spec—fast.
FAQ
CTO-015 FAQ
What is CTO-015 and what is it used for?
CTO-015 is a Strong Longpass-like CTO with Rising Red-NIR Profile. CTO-015 delivers powerful warm shift with characteristic longpass-rising behavior, featuring 50 % transmission at 580nm and 95.3 % peak at 728nm. Red reaches 91 %, NIR extends to 95 %, with blue suppressed to 18 %, creating strong warm correction with progressive red-infrared emphasis. Common uses include Cinematography with Infrared Capability, Professional Thermal Imaging, Warm Cinematic Grading, and Research Thermal Measurement.
What are the key optical specs of CTO-015?
Key published specs for CTO-015 include Colour shift direction: Warming (5600 K → 3800 K); Mired shift: +67 Mired; Correction strength: 1/2 CTO; Average transmittance: ~55.2 % T (visible range); Peak transmittance: ~95.3 % T near 728 nm.
What applications is CTO-015 best suited for?
CTO-015 is commonly used for Cinematography with Infrared Capability, Professional Thermal Imaging, Warm Cinematic Grading, and Research Thermal Measurement. Cinematography with Infrared Capability - Deliver strong warm tungsten shift while preserving infrared sensitivity for cinematography systems with dual-band or thermal imaging integration.
Can CTO-015 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTO-015 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. Custom Specifications Available - Round (5-450mm), square, free-form geometries on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG; 0.21-3.8mm thickness options.
What should I know about angle of incidence and durability for CTO-015?
The ion-assisted hard-oxide coating is built for repeated handling, heat, and cleaning.
