Ah, indeed. Since these are probably just two colors, you could do this by using the Burn channel as a 2nd smoke channel. In your renderer you can then setup a 2nd smoke shader with different colors using the Burn channel as input.
If you are using C4D’s builtin renderer,
- add a 2nd container and point it to the cache created by the first one,
- setup the smoke shader on the 2nd container to use the Burn input channel and a different color
This works OK if you have only two colors to deal with.
In the future you will be able to use any number of custom channels as well as an RGB channel for arbitrary colors. Unlike the above approach, this will also allow doing sth. like this: