Both. Each color is a separate object. On the saucer I used 20 or 50-step blends from smaller inner objects to the outer outline. Sometimes the start and finish objects had fountain fills. The nacelle is entirely fountain blends, ingoring the taper for my sanity's sake. The bottom of the saucer is blends, but them I added a black graduated transparency to simulate shadow, PLUS a second black graduated transparency on the right edge to shad the dish shape, PLUS a white graduated transparency on the left for the highlight. I don't think it's perfect, but I tend to settle for what looks good enough without making me insane.