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Understanding Spectrum Control

The release of firmware 0.7B for RR and R2 fixtures introduces video RGB pixel mapping profiles with Spectrum Control

The Spectrum Control DMX parameter is found in the RGB-VW and VRGB profiles (P23-P24 and P53-P66) that were introduced in firmware 0.7b. Not all LED's produce the same results at the same settings. So the Spectrum parameter allows you to adjust the whitepoint and color response of any Quasar Science RR and R2 fixture to try and match the color spectrum of a different manufacturer's LED diode set.

Since video RGB signals work with a relative colorimetric space, changing the white balance should change the grayscale color but also maintain the color differences throughout the image versus the grayscale color. This behavior lines up with the concept of a Relative Colorimetric space that maintains color and light behavior.



The Spectrum parameter works with our Relative Colorimetric color spaces (i.e Rec709, sRGB, etc) versus the native RGBX color engine (called "Absolute Hue") which is designed to maximize saturation and brightness output.

The Spectrum Control parameter adjusts the light spectrum output for any given color setting produced by the RGBX LED engine color gamut:

  • At a 0% input value, the desired color uses only the RGB diodes to produce a spike-y spectral output similar to cheaper LED fixtures..

  • At 100% input value, the desired color uses Quasar Science's entire RGBX diode set (R,G,B,T,D), resulting in the highest possible SSI from RR-R2's 5-diode set.

  • Any intermediate value proportionately blends the two calibrations for the entire possible range of significant diode combinations for a given color setting.

For example, for the given CIE 1931 x, y chromaticity coordinate for 3200K white light, the diagram below shows the 0%, 50%, and 100% settings for 3200K. Each setting would provide the x, y chromaticity value that matches 3200K:


This control provides both the technical and creative means to truly control the fixture’s entire range of output with the use of a single dmx parameter.

A technical application might involve matching other lighting sources on set with similar LED diode sets:


A creative application could involve intentionally producing color changes without changing the image’s white balance:


For further information, please deep dive into the Quasar Science color engine within our RGBX Spectral Science section.