CTB-001 Color Temperature Blue (Cooling) Filter
Full CTB colour-conversion filter shifting 3200 K toward 5600 K for seamless mixed-lighting balance in broadcast, film, and architectural applications.
- Colour shift direction: Cooling (3200 K → 5600 K)
- Mired shift: −131 Mired
- Correction strength: Full CTB
- Average transmittance: ~38.1 % T (visible range)
- Peak transmittance: ~91.9 % T near 401 nm
- Minimum transmittance: ~13.2 % T near 737 nm
- Construction: Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick
- Custom options: Intermediate Mired shifts, combined CTB+diffusion, custom sizes, rapid prototypes
Learn more
CTB-001 CTB delivers Colour shift direction Cooling (3200 K → 5600 K), Mired shift −131 Mired, and Correction strength Full CTB.
The hard-oxide coating is built for repeated handling, heat, and cleaning.
Best suited for:
Full CTB correction is designed for complete tungsten-to-daylight conversion — matching a 3200 K source to 5600 K daylight-balanced fixtures and ambient light
Description
CTB-001 is a broadband, glass-based “cool-blue” correction filter that selectively boosts the blue content of warm white or tungsten sources without stealing too much punch. Transmission peaks above 90 % at ~410 nm, stays ≥ 60 % to about 500 nm. Past 500 nm the curve slopes down smoothly—dropping below 40 %, hitting ~25 % around 560 nm, and flattening near 15 % through the far red—so excess red energy is trimmed and a 3 200 K lamp can shift convincingly toward a daylight look, or an LED fixture can hit a higher CCT with minimal loss in output.
Key advantages
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High blue throughput (390 – 510 nm, ≥ 60 %) – Preserves luminous output while delivering the chromatic lift needed for CTB correction.
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Progressive red attenuation – Smooth roll-off tames yellow/red without introducing an unwanted green cast.
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Single-surface, low-ripple coating – Avoids the beam distortion and ghosting typical of stacked plastic gels.
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Heat-resistant oxide formulation – Survives high-power tungsten halogen and LED engines where polymer gels fail.
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Custom formats on demand – Round, square or free-form parts from 5 mm to 450 mm in diameters, 0.21 – 3.8 mm thick, on Borofloat®, soda-lime, Schott D263 T or Corning Eagle XG glass.
Typical applications
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Stage & architectural lighting – Cool tungsten or warm-white LEDs toward 5600 K without disposable gels.
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Film & broadcast production – Balance practical incandescent sources to match daylight HMIs or sunlight.
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Photography flash modifiers – Fine-tune studio strobes for mixed-light environments while keeping output high.
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Museum & retail displays – Improve colour rendition of exhibit lighting without adding UV that could damage artwork.
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Machine-vision & inspection – Boost blue-channel contrast for detecting optical brighteners or fluorescent tracers.
Need prototypes next week or high-volume lots next quarter? CTB-001 filters can be coated, cut and shipped to your exact specifications—fast.
For customization options, including cutting to any size or shape to meet your specific requirements, please contact us today! By selectively enhancing blue wavelengths and reducing longer visible components, the CTB-001 filter offers a reliable solution for precise color correction and cooler-toned illumination.
FAQ
CTB-001 FAQ
What is CTB-001 and what is it used for?
CTB-001 is a Steep Blue Shift for Tungsten to Daylight Conversion. The CTB-001 delivers aggressive color temperature correction, shifting tungsten-balanced lighting (3200K) decisively toward daylight (5600K+). With a steep transmission profile peaking at 91.9 % at 401nm and 50 % transmission at 522nm, this filter prioritizes blue wavelengths while actively suppressing red and infrared energy. Common uses include Tungsten Film Production, Cinematic Cooling, Stage and Theater Lighting, and Video Production.
What are the key optical specs of CTB-001?
Key published specs for CTB-001 include Colour shift direction: Cooling (3200 K → 5600 K); Mired shift: −131 Mired; Correction strength: Full CTB; Average transmittance: ~38.1 % T (visible range); Peak transmittance: ~91.9 % T near 401 nm.
What applications is CTB-001 best suited for?
CTB-001 is commonly used for Tungsten Film Production, Cinematic Cooling, Stage and Theater Lighting, and Video Production. Tungsten Film Production - Convert 3200K tungsten fixtures to 5600K+ daylight equivalent for mixed-source lighting scenarios in studio and location work.
Can CTB-001 be customized for size, substrate, or coating requirements?
KUPO lists the construction for CTB-001 as Ion-assisted hard-oxide; 5 – 450 mm shapes, 0.21 – 3.8 mm thick. Published custom options include Intermediate Mired shifts, combined CTB+diffusion, custom sizes, rapid prototypes. Custom Substrate and Format Options - Available in round (5-450mm), square, and free-form geometries on Borofloat, soda-lime, Schott D263 T, or Corning Eagle XG glass with thickness from 0.21-3.8mm.
What should I know about angle of incidence and durability for CTB-001?
The hard-oxide coating is built for repeated handling, heat, and cleaning.
