pretty much, you can also lower the opacity, filter if u need too, or press [ctrl+u] to change the color too match your render; or [ctrl+shift+u] to make it black and white
lots of things, simplest of which is chaning the settings, like soft light/screen etc. and dropping the opacity, you can change the colors. you can use filters on them, just don't make them your damned background! c4ds are meant to be subtle and ADD to the flow, not change it.