CTB-200 Cooling color-correction filter

CTB-200 is a cooling color-correction filter. It transmits more of the blue region than the red region.

Measured wavelength range: 380-780 nm
400-500 nm: 94.9% average transmission
500-600 nm: 30.2% average transmission
600-700 nm: 17.4% 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-200)

CTB-200 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 94.9% over 400-500 nm, 30.2% over 500-600 nm, 17.4% over 600-700 nm. The resulting light output also depends on the lamp spectrum.

Optical performance

Measured wavelength range: 380-780 nm. Performance outside this measured interval is not established by this curve.
400-500 nm: Approximately 94.9% average transmission; the range is 87.4-95.7% in the measured curve.
500-600 nm: Approximately 30.2% average transmission; the range is 11.5-87.4% in the measured curve.
600-700 nm: Approximately 17.4% average transmission; the range is 12-22.6% in the measured curve.
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-200

How does CTB-200 balance the visible wavelengths?

The measured averages are 94.9% over 400-500 nm; 30.2% over 500-600 nm; 17.4% 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.

Can I predict the brightness after CTB-200 from these three averages?

The 94.9% average over 400-500 nm gives each measured wavelength equal weight; an LED may concentrate its output in a narrow peak within that interval. Look up your actual emission wavelengths on the CTB-200 curve, or evaluate a sample with your source and detector.

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