Dynamic white point for indirect color mixing

[danielmuellerma]

At the moment the white point in the definition of the color space for indirect color mixing has a fixed color temperature. There are fixtures that make use of a dynamic white point that can be controlled by a DMX channel. The DMX Channel only affects the non-saturated colors, not the saturated ones. What we would need is the possibility to link the white-point to a channel function and a new attribute for this behavior.

[PSchulze-ARRI]

The ARRI SkyPanel and Orbiter have a "floating" White Point when using calibrated color. In a couple of our modes, we have the option for White (CCT) control or Color. In these modes, the CCT and Tint channels set the White Point. The Orbiter has separate White Point and WP Tint channels. The difficulty is having two sets of channels with the same "Attribute" but being related to separate areas of functionality. Color 1, Color 2, etc., is an option, but not CCT1, CCT2

[petrvanekrobe]

The ARRI SkyPanel and Orbiter have a "floating" White Point when using calibrated color. In a couple of our modes, we have the option for White (CCT) control or Color. In these modes, the CCT and Tint channels set the White Point. The Orbiter has separate White Point and WP Tint channels. The difficulty is having two sets of channels with the same "Attribute" but being related to separate areas of functionality. Color 1, Color 2, etc., is an option, but not CCT1, CCT2

Are these attached to the same geometry? In some cases, adding more "depth" to the description - a geometry "background", "foreground", holding the mixing could help i presume, since you can have more CCR channels this way. (At this point, these geometries already serve a function of being the logical container and i hope that in the future we can add more properties to them, to indicate how they are affecting the beam (priority, mode of adding/subtracting from the beam...)).

[PSchulze-ARRI]

Hi Petr, They are currently attached to the same geometry. As I mentioned, we have modes that allow both CCT and Color, depending on where the ColorCrossfade Channel sits. When on the “White” Side, individual control of the colors is inactive…the fixture uses them to calculate the desired CCT/Tint output. When the fixture is set to Calibrated Color, it uses the CCT/Tint channel levels on the “White” side to determine the Calibrated White Point. This is for the SkyPanel only. The Orbiter, when in Calibrated Color, becomes a “virtual” RGB(W) fixture. It still uses all 6 native colors to do its calculations, but the user controls RGB, and a virtual White Channel, IN ADDITION to another set of CCT/Tint channels on the “Color” side of the crossfade, instead of using the main CCT/Tint channels on the “White” side of the Crossfader. R+G+B at full = whatever White Point is set. Conversely, R+G+B at zero and White at full ALSO= whatever white point is set. When mixing RGB, adding the W channel serves to desaturate the color. All of this math is done inside the fixture, using all six colors of the Light Engine (RGBACL).

I’m sure that visualizing this may be a challenge, but now you see how we’ve been creating the color. As a point of reference, the SkyPanel is an RGBW source with a CCT range of 2800K to 10000K. The Orbiter is a 6 Color (RGBACL), with a CCT range of 2000K to 20000K.

Copying in my colleague, Dan Reed, who is our PM and was on the call with us yesterday. If you see the need for us to change geometries to make things work, we are obviously open to that. Unfortunately, we are still hindered due to the fact that there is reluctance to disclose colorimetry surrounding our Light Engine. I’ll let you and Dan discuss.

Thanks so much for all of your help and support during this process!

Patrick

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Patrick Schulze Lighting Systems Engineer ​ ARRI Inc. 3700 Vanowen Street Burbank, CA 91505 www.arri.com

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From: petrvanekrobe @.> Sent: Monday, March 29, 2021 11:08 PM To: mvrdevelopment/spec @.> Cc: Patrick Schulze @.>; Comment @.> Subject: Re: [mvrdevelopment/spec] Dynamic white point for indirect color mixing (#67)

The ARRI SkyPanel and Orbiter have a "floating" White Point when using calibrated color. In a couple of our modes, we have the option for White (CCT) control or Color. In these modes, the CCT and Tint channels set the White Point. The Orbiter has separate White Point and WP Tint channels. The difficulty is having two sets of channels with the same "Attribute" but being related to separate areas of functionality. Color 1, Color 2, etc., is an option, but not CCT1, CCT2

Are these attached to the same geometry? In some cases, adding more "depth" to the description - a geometry "background", "foreground", holding the mixing could help i presume, since you can have more CCR channels this way. (At this point, these geometries already serve a function of being the logical container and i hope that in the future we can add more properties to them, to indicate how they are affecting the beam (priority, mode of adding/subtracting from the beam...)).

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