[SML] Moving Light Colour Mixing philosophy question

[Bruce Bennett]

We are pretty happy with our Robe T1-PC & T2 additive mixing movers.
They replaced VL-1000 Arcs in a concert hall.
Bruce

> On Jan 13, 2026, at 17:43, Riter, Andrew via Stagecraft <stagecraft at theatrical.net> wrote:
> 
> Thank you all.  Interesting.  This could be a good discussion.
> 
> 
> I like Jerry's point of white source = all colours / RGB = spiky RBG versions of a colour, so subtractive is better colour.  But subtractive is also less intensity in the saturated colours.
> 
> The question is more:  why are subtractive systems  CYM and not RGB?
> 
> 
> 
> Andrew M. Riter 
> Assistant Technical Director, Head Lighting Technician
> Chan Centre
> 
> Phone 604 822 2372
> andrew.riter at ubc.ca
> 
> -----Original Message-----
> From: Stagecraft <stagecraft-bounces at theatrical.net> On Behalf Of *Hobbit* via Stagecraft
> Sent: Tuesday, January 13, 2026 12:48 PM
> To: stagecraft at theatrical.net
> Cc: *Hobbit* <hobbit at avian.org>
> Subject: Re: [SML] Moving Light Colour Mixing philosophy question
> 
> [CAUTION: Non-UBC Email]
> 
> I found that it helped to think of CMY as RGB turned upside-down, in terms of what sliders do.
> 
> For why CMY is still there, if it's a profile unit that needs beam consistency all the way through complex optics, RGB(AW) chips would probably get weirdly patchy by the time the light hit a target.  Some "par" units do that too, and need some strategically-placed frost to even out the wash a bit more.  I guess nobody's yet making a multi-color COB emitter?  Possibly more efficient too, but I haven't researched the LPW of those vs. typical multi-chip emitters.
> 
> _H*
> 
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