Oh, I should mention, you can ignore and omit the HSV node plugged into PoserSurface:Specular_Color. The idea was to be able to see what the hues would be in a preview without rendering, but it's turned off here and does nothing at all.

Much of this is fakery of the first order. You'll notice there's no connection between the IOR in the Fresnel_Blend node and that used for the surface reflectivity. Feel free to adjust the Fresnel_Blend IOR to your taste, as it only affects the rainbow banding. The soap bubble isn't showing real refraction. If you changed the GlossyBSDF nodes in the Compound_Metal shader for GlassBSDF, you could play with different results including refraction. But remember, a soap bubble is a thin membrane, so you'd really want two nested spheres to represent the inner and outer surfaces of the bubble.

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My ShareCG Stuff

Verbosity: Profusely promulgating Graham's number epics of complete and utter verbiage by the metric monkey barrel.