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Optical Color Mixing
I’m trying to achive a “realistic” color mixing of 2 layers,
where eg. blue and yellow result in green… I know this
could be probably solved in subtractive/CMYK mode, but I
wasn’t able to create a fully working setup … any ideas
or plugins to recommend?Thanks, Rob
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10 Replies
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DId you try the different transfer modes? There is unique math to each as how each color lays over another color.
Chris Smith
https://www.sugarfilmproduction.com -
I just tried messing with transfer modes, and I think that won’t allow anything other than RGB mixing … mathematically, of course.
If you’re talking about blue and yellow circles intersecting, I’d animate the circles’ motion, then create a duplicate set of circles that move in the same way. Those circles would be black and white (probably), so that their motion would create something visible only at the point of intersection of the circles. You would then use this intersection as an alpha matte for a green solid, so the green solid is revealed by the object that represents the intersection of the circles. It’s clumsy, but it should work.
To do the intersection, you might set the transfer mode of the upper circle (s) to stencil alpha.
You could probably use expressions or parenting to tie the dupe circles to the motion of the original circles.I hope someone has a better idea … 🙂
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The ‘Vivid Light’ transfer mode seems to do it for me. Yellow over blue makes green.
Chris Smith
https://www.sugarfilmproduction.com -
Lovely, Chris. Guess I shouldn’t have put blue over yellow. 😛
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For simple setups this works, but if you have really complex
layers with both color components it’s not that easy. I think
this really a more mathematical issue…But thanks for the fast ideas, Rob
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You’re probably right. If the blue over yellow resulted in the same green as yellow over blue I would say the transfer mode works but since it only works one way, that blows the deal. Now I’m curious to find the right solution 😉
Chris Smith
https://www.sugarfilmproduction.com -
Well, if you put the top layer to multiply and set both layer’s opacity lower than 100% you are getting the combination effect. Like with yellow over blue. Yellow to multiply and it’s opacity to say 75% then set the blue to 75% and you get a green. Then you can reverse the colors and it will have the same result.
The color is darker than the original 2 which would happen optically. However it seems the saturation is lower than the 2 where optically I would think it would be the same or richer (increased color saturation).
Chris Smith
https://www.sugarfilmproduction.com -
Hmm … I don’t look into this kind of math generally, but I wonder if it’s possible (inspired by your response, Chris) to do math on HLS values rather than RGB values?
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You can use the Channel Combiner to convert RGB to HLS
and back, which could be helpful. I had some luck with
YUV conversion, but only for full colors, not shades…@Chris: The Mulitplied/75%opactiy looks very faded,
but is something I completly overlooked. Raising the
saturation introduces artefacts, even in 16Bit and it
the image still looks dull…Thanks for helping me out! Rob 🙂
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Any ideas? It would be nice to have a Filter Factory for
After Effects to solve these things …
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