How to use WHITE in RGBW Matrix?

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Baylink
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Re: How to use WHITE in RGBW Matrix?

Post by Baylink » Fri Apr 01, 2016 7:40 pm

mcallegari wrote:Alright thanks, Robert's Excel studies seem the most scientific to me :)

One thing I don't understand though: after calculations on RGB channels, what is the contribution of the white channel ? The original one (column E) ?
Basically on RGBW_equation2.xlsx I would expect to see an additional column (N ?) with the final W value.

Also, there's one more thing to consider. At the moment, RGB scripts work only on RGB channels. Changing them for additional channels would be a mess, and moreover depends on what kind of fixtures you're using.

Indeed a delicate topic...
Indeed. :-)

Disregarding the UV and such channels for the moment, this is an issue of colorspace mapping, and it's similar to what takes place inside a RIP when you're going from RGB image files to CMYK toner; not only do you have to convert RGB to CMY, you then have to figure out how much black to replace the colors with, an issue that depends on the gamuts of all 4 toners.

The issue will be the same here -- for any given combination of colors, you have to decide how much of it to replace with white, and how -- and what the best way is to do it depends a lot on who the audience is and what they're using it for.

My snap reaction is that the right answer is to switch the users over to entering either HSB, or HLV, probably HSB, and then convert that to RGB or RGBW (which is usually a cool white), or RGBA, internally on the way to the fixture.

You could actually still allow entry in RGB, even; store all colors as both HSB *and* the components, and leave whichever one wasn't entered as all 0's; then convert on the way out if necessary. That allows, even, dealing with multicomponent fixtures (RGBAWU, or things like the 6-color ETC's), and puts the translation tables/formulae inside the fixture machinery, where it belongs, without keeping you from being able to access individual components if you need to.

It would also make colors stored in cue sheets portable across fixtures, as much as that's possible.

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pipolino419
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Re: How to use WHITE in RGBW Matrix?

Post by pipolino419 » Sat Apr 02, 2016 11:30 pm

It is true that it is frustrating not to have the white output live on the channel W. The Full RGB mix is ugly on the LEDs. But the matrix is so interresting that one would like it to be perfect. RGB or CYM or RGBW and not RGBWAUVPINK :) Robert:)

bestdani
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Re: How to use WHITE in RGBW Matrix?

Post by bestdani » Sun Apr 03, 2016 10:24 am

Just my two cents to this discussion because I also made my mind around it since I've some RGBA fixtures and there are other "exotic" types of fixtures and many DMX software has some trouble dealing with all them: I came to the conclusion that the best way would be probably if "the user" could define own rules for example in the fixture editor when and how the additional channels should become active, I did not made my mind around how this could be done exactly though, I guess a combination of simple conditions and math could do the job like:

Code: Select all

if(R > ... && G > ...) A = (2*R + G) / 3
or

Code: Select all

if(R != 0 && G != 0 && B != 0) W = (R + G + B) / 3
More abstract maybe: I think finally it requires something where in the fixture editor one can define how the values from QLC+ RGB color space can be transformed into the fixtures color space and QLC+ should be strictly use RGB. I guess this would even allow you to interpret QLC's RGB values as HSV for your fixture and other fancy stuff.

MrTK
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Re: How to use WHITE in RGBW Matrix?

Post by MrTK » Wed Apr 06, 2016 3:44 am

Just create a "million" buttons / faders, one for each pixel on the light @ white only + intensity.. Set your looks, and then record it straight into a chase.. 2 or 3 chases shouldnt take too long.. :) heheheh,, I did this once with just rgb par cans and a ETC EXPRESSION3. good luck.. I think this is the second time ive recommended something like this, hope ppl dont think im joking.. Just have fun and try it.

3rdPlanetRob
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Re: How to use WHITE in RGBW Matrix?

Post by 3rdPlanetRob » Tue Mar 14, 2017 7:07 am

Pardon me for butting in, you guys are a bit over my head, but i wanted to second (third?) the request (rgbw capability in matrices), i had mentioned it before, but i know in the programming sometimes things are far more complex than they seem. I never got past hello world in my own programming.

I also wanted to suggest the possibility of... black? It would make patterns in the lighting stand out so much more. I've been playing with mostly plasma and gradient "patterns" in matrices, and they make some amazing effects when you adjust the parameters right. Especially when you combine plasma, gradient and other patterns together in the same matrix you can get some really amazing and subtle pulsing effects, it seems like so much more could be done with more color options. But again i know how much more complicated the programming can get.

Thanks!

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