Quasar Science - Help Center

CCT

The RGBX diode set provides 1750K to 10,000K calibrated SPDs with Spectral Similarity Index (SSI) scores ranging from 61 to 91* when compared to the TM-30-18 reference illuminant SPDs. Quasar Alchemy calculated diode combinations from RGBX for the highest SSI score possible from its diode set for any given CCT.

+/- Green

Quasar Alchemy also internally developed a new set of +/- Green targets based upon theoretical CC36G and CC30M Wratten filters combined with the TM-30-18 reference illuminant SPDs. Since real filters & gels create undesired CCT shifts while adjusting the green/magenta tint (duv), the RGBX SSCE addresses this problem by maintaining the CCT for +/- Green adjustments.

Since a portion of the Full Plus Green chromaticity range extends beyond the RGBX LED gamut, Quasar Alchemy also calculated the unreproducible Full Plus Green chromaticity range: 2470K to 1750K. Furthermore, from 1850K to 1750K, no achievable amount of + green adjustment (+ duv values) exists in RGBX, so the engine outputs CCT light values for + G adjustments in this CCT region.

Perceptual Threshold Manual Control

Most lighting fixture digital controls do not provide even color change increments of CCT control throughout the Kelvin range. For example, a 50K increase at 2500K produces a greater noticeable color change than a 50K increase at 5600K.

Instead of allocating too many CCT increments (or too few CCT increments) by using fixed Kelvin adjustment increments, Quasar Alchemy allocated the full 1750K to 10,000K CCT control range into 1 Just Noticeable Difference (JND) increments, i.e. a distance of 0.0011on the CIE 1976 u’v’ chromaticity diagram. Each CCT control division therefore yields a consistent chromatic change at the minimum human perceptual threshold. This feature provides the most intuitive CCT control feel versus any other lighting product on the market.

Hue

The RGBX SSCE has defined its absolute Hue angles by mapping key points in the RGBX LED gamut to established monochromatic wavelengths for different colors.

It also has determined the most spectrally accurate mix possible for the RGBX LED diode set between Hue angles 0° to 120°.

It then equally divides up each hue between these eight primary and secondary colors to provide the most even amount of saturated hue color control.

Hue Intensity Equalization

Quasar Alchemy created Hue Intensity Equalization (HIE), an advanced under-the-hood calibration feature to provide the most even exposure of saturated color with respect to the light’s white point.

As seen in the left figure, the blue diode natively outputs about 4-5 times the amount of spectral energy in the blue region of RGBX SSCE 4300K white light.

This intensity difference cannot be measured by traditional incident or spot light meters. Blue illuminated objects often overexpose or clips in photographic images, especially when lighting effects transition between this saturated hue with others. This overexposure lies at the heart of what is often mistaken for a “color gamut” problem.

Quasar Alchemy profiled each RGBX diode for its energy in relation to its relevant counterpart in TM-30-18 reference 4300K SPD and wrote a software algorithm in the R2 and RR firmware to automatically adjust any saturated light intensity to its relevant region in 4300K light. Future development and updates will dynamically equalize to the currently set white point.

Saturation

RGBX SSCE defines saturation as the % mix between an SPD from its white point engine and the absolute Hue angle at the edge of the RGBX LED gamut. 50% saturation describes the halfway point on the CIE 1976 u’v’ diagram between the white point and the Hue.

RGBX SSCE can now take direct CIE 1931 xy chromaticity value input and allows control of its full range of spectral variations for any one of those chromaticity inputs.

This input comes currently in the form of DMX control profiles. The CIE 1931 xy DMX control profiles expect: Channel 1— intensity value in %; Channels 2 & 3— x and y values ranging between 0 to 0.8, scaled to 0% to 100% of the channel value; and Channel 4— Spectrum control value.

The conversion formula for Channels 2 & 3 is (input x or y value)/0.8 = DMX %. For example, a desired coordinate of x = 0.31 and y = 0.31 must be transmitted as 0.31/0.8 = 0.3875, or 38.75% for each channel.

For Channel 4, RGBX SSCE has been calibrated to provide the RGBX diode set's entire range of spectrum possibilities for each point in the entire device's gamut. Please refer to the follow section for further explanation of this novel feature.

Spectrum Control

RGBX SSCE now provides Spectrum Control, a novel color control feature that provides the full range of spectral possibilities for any given color value. Since an infinite array of spectral fingerprints (technically called illuminant metamers) can generate any desired xy or u'v' chromaticity value, R2 and RR fixtures now have full calibration to provide any possible spectral combination as seen in the below illustration for 3200K white light:

This function serves both technical and creative purposes. It can either be used to provide any level of spectral quality to match or complement other fixtures in a lighting setup, or it can be used to provide a dynamic creative lighting effect in real time.

Currently, this function can only be accessed via the CIE 1931 xy chromaticity DMX profile. (DMX Profiles with the Color Space Parameter). When chromaticity control is fully integrated into manual control, the Spectrum Control will also be a manual control parameter.

Parameterized Calibration

Underneath the hood, the RGBX SSCE uses dynamic equations to implement device color calibrations. This software design philosophy creates: