This one was a real challenge; It was about the sky - a deep blue Canterbury spring sky. But, whenever I pushed the saturation and luminescence sliders to get the depth of blue I wanted, all I got was horrific posterisation (banding) in the sky - even editing at 16 bits. Eventually I decided on a masked multiply layer rather than pushing the individual colour values and this had the desired effect without any banding artifacts. Another lesson learned.
Eyre River, near Oxford, looking towards the Alps. Two frame stitched panorama, 50mm, 1/160, f11.