I need it. I couldn't find it. I made it.
The RGBCMYBW Separator splits 8 colors (red, green, blue, cyan, magenta, yellow, black, white) into separate black/white channels. It can be used to separate color IDs from vertex color to help with texturing.
Important: Each incoming channel (RGB) is rounded to 0 or 1. This makes sharp edges between colors. This prevents unwanted overlapping with mixed colors and you don't need to be very accurate while coloring. Only white needs to be very white.
I'm using the RGBCMYBW Separator with absolut vertex colors just to quickly preview some parts with a material while excluding or simplifying (eg. Diffuse) others to speed up the preview render while keeping the hole model in perspective. For example I can preview the metal parts without rendering complex non-metal parts (eg. procedural woods are heavy) and keep the whole thing in view. The vertex color maps are needed for color ID maps for texturing anyway.
It's not meant to be a RGB to CMYK converter. I'm surprised there is no one here on blendswap! The math is not very complicated. Or is there one in blender already? Is it even needed in blender?
Heya, It seems we've both thought of similar methods of doing this color separation thing. I made my thesis about a very similar method, although it was for UDK and realtime graphics at the time. My theis is in the finnish language, but I've included a lot of pictures in the text too, some example scenes also. you can find it here if you are interested: https://www.theseus.fi/handle/10024/74000 https://www.theseus.fi/bitstream/handle/10024/74000/Opinnaytetyo_Jassu_Ilama_2014.pdf?sequence=1&isAllowed=y
Anyway, good work :)
I still have to figure out how to use It well.. but for me is a yes vote :)
so with this.. exporting CMYK should be easier, i suppouse..