from asprague
What *is* banding???? Maybe a pic with a fish and an arrow pointing toward the banding might help us dummies out here.
Banding is a bit hard to explain. It's not a lack of colors, because both the .99H version and my mocked-up version of the Purple Tang both start to lose definition when you try to bring the number of colors down below 350. It's as if, somewhere along the way from the original texture map, to the final version, color definition was severely clipped to something like 128 colors (6 bit) or worse.
I think the compression engine being used by Jim is seeing similar areas of purple and throwing away too much relevant information. And actually, the Purple Tang and Powder Blue Tang also exhibit some color
splotching where incorrect interpolation of colors is being introduced to the image. If you look at the Purple Tang, many of the purple colors have shifted to brown and green in splotches.