@Override
    public void read(JmeImporter im) throws IOException {
        super.read(im);
        InputCapsule ic = im.getCapsule(this);
        color = (ColorRGBA) ic.readSavable("color", ColorRGBA.White);
    }
sets the color

@param color the desired color (default=(1,1,1,1), alias created)
jme3-effects/src/main/java/com/jme3/post/filters/ColorOverlayFilter.java