Maybe this has been covered before, but I couldn't find it.

My particle colors are not the color I specified.

This feature only seems to work properly if I use various greys.
If I choose another color, the result is usually 2 or 3 different colors. Sometimes this is also compounded by the fading effect when particles die (instead of fading smoothly the change to a different color)

I am currently using NovaTools. And I thought that perhaps the color picker was letting me pick values that EVN didn't handle. So then I tried using just web colors, and that didn't work either.

What is the trick to this?

I've had the same problem with messing around with trail colors, sometimes getting multi-colored trails with no explanation. Just fiddle around with the colors, and try going with lighter and more dilluted colors.