So I've been working on smoothing the haze in the sky above the city. The first thing I did was go back to Lightroom for a version of the photo that had not been autotoned - pushing the exposure up and then dragging it back down worsened the banding considerably. But the sky and water were too dark, so I wanted to drop them closer to black. I added another curves adjustment layer, magic-wanded the haze, and applied a gradient to it in the layer mask - and it looks pretty good.

So I went ahead and printed a strip, which is good. Then I toggled the gamut warning and noticed that the curve had taken most of the bridge tower out of gamut. But the printout looked fine, even compared to other prints which I know are in gamut. So what the heck?

Andrew Rodney says that these days the gamut warning is pretty useless, so I will probably not use it anymore.