CTB-009 Cooling color-correction filter

CTB-009 is a cooling color-correction filter. It transmits more of the blue region than the red region.

Measured wavelength range: 380-800 nm
400-500 nm: 76.8% average transmission
500-600 nm: 53.4% average transmission
600-700 nm: 48.9% average transmission
Custom options: Wavelength response, dimensions and operating conditions

Values shown are sample measurements. Final specifications are agreed for your order.

Cooling color-correction filter (CTB-009)

CTB-009 is a cooling color-correction filter. It transmits more of the blue region than the red region. This can give a warm light source a cooler balance. Average transmission in the sample is 76.8% over 400-500 nm, 53.4% over 500-600 nm, 48.9% over 600-700 nm. The resulting light output also depends on the lamp spectrum.

Optical performance

Measured wavelength range: 380-800 nm. Performance outside this measured interval is not established by this curve.
400-500 nm: Approximately 76.8% average transmission; the range is 65.1-86.5% in the measured curve.
500-600 nm: Approximately 53.4% average transmission; the range is 48.5-65.1% in the measured curve.
600-700 nm: Approximately 48.9% average transmission; the range is 48.5-49.5% in the measured curve.
Measured edge at 70% transmission: Approximately 484.2 nm. Interpolated absolute-transmission crossing, checked against the factory summary.
Customization: We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.

These values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.

Applications to consider

Film and broadcast lighting: Consider cooling a warm source toward the color of another fixture. Check the resulting color temperature and tint with the actual lamp and camera.
Stage color shaping: Try it when you want a bluer lighting effect. Account for the transmitted red and green content rather than expecting monochromatic blue.
Lighting-fixture development: Compare the spectrum and brightness of the filtered light with other correction filters before choosing a strength.

Choosing this filter

Evaluate the filter together with the intended light source. Color temperature, tint, color rendering and luminous output depend on that combination.
Tell us the size, shape and working angle you need, along with the temperature conditions inside the fixture.

Custom options

Start with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.

Transmission spectrum

Questions about CTB-009

How does CTB-009 balance the visible wavelengths?

The measured averages are 76.8% over 400-500 nm; 53.4% over 500-600 nm; 48.9% over 600-700 nm. They show how the filter weights different parts of the visible spectrum; the resulting color depends on which wavelengths your lamp supplies.

What does the 70% crossing near 484.2 nm mean for CTB-009?

It identifies where this measured curve crosses 70% transmission. It is useful for comparing the spectral transition, but it does not give a fixed color-temperature shift or the total light output from your lamp. For CTB-009, use the band averages above together with your source spectrum.

Discuss this filter with KUPO - include the product reference, source wavelength, working angle and required dimensions.