HMG-4 Minus-green correction filter

Minus-green correction filter (HMG-4)

HMG-4 is a minus-green correction filter. It attenuates part of the green-to-yellow region relative to surrounding wavelengths. This can help reduce a green cast in lighting. Average transmission in the sample is 71.6% over 400-500 nm, 66.3% over 500-600 nm, 85% 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 71.6% average transmission; the range is 64.8-77.2% in the measured curve.
• 500-600 nm: Approximately 66.3% average transmission; the range is 62.7-74.1% in the measured curve.
• 600-700 nm: Approximately 85% average transmission; the range is 74.1-90.5% in the measured curve.
• Measured edge at 70% transmission: Approximately 504.7 nm. Interpolated absolute-transmission crossing, checked against the factory summary.
• Measured edge at 70% transmission: Approximately 588.4 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

• Mixed-source film and studio lighting: Try it when matching fixtures that have different amounts of green in their light. Choose strength by measuring the resulting tint.
• Photography and camera matching: Consider spectral tint adjustment at the light source before camera profiling. Confirm the effect on the colors important to the shoot.
• Luminaire color tuning: Compare minus-green filters with your actual light source, and check how much light each one removes.

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.