Well here is what Saturn looks like in Space Engine. It has a little bit of colors in it's rings, but nothing that would look like a cartoon. So a small degree of color variation may be realistic. I have to agree with Talisman that the procedural rings are a bit dark right now.Added (06.05.2013, 21:09)
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Has anyone looked into this at all, aside from the troll image posted above? Saturn's rings are moderately gold-silverish but all procedural planet's rings are very dark if not black.