Originally Posted by retinax
Here on this planet the sky is definitely very very continuous in color when/where devoid of clouds, and I don't see why digital wouldn't capture it if it were otherwise. But film grain/dye clouds does look nice on a sky. If it is actually resolved, like on a good scan or a sharp wet print.
Skies are interesting subjects. They can be heterogeneous even when clouds aren't visible to the eye. In digital photography skies cause confusion.
In digital images the brightest, clearest sky will render with photon noise even at low ISO settings with perfect exposure. I have read comments from new digital camera owners where they suspected their camera was defective since they saw noise when pixel peeping a bright sky. One of the most common errors in digital photography is to unintentionally clip the blue channel when a bright sky is in the scene. At low levels this will result in a color cast. If there is insufficient bit resolution, then there will be color banding artifacts. Color banding is caused by excessive JPEG compression. Contour banding occurs when 8 bit rendering results in color quantization which creates false tonality differences. Coincidently, photon noise dithers color quantization errors which reduces banding.
There is no fundamental reason digital images can't render aesthetically excellent sky regions.
Film has issues with skies as well. Film grain always produces spatial uncertainties. Low grain film produces the least amount of spatial uncertainty, but it is never zero. Any aspect of film production, development, or printing that results in density fluctuations greater than 1% will resulting perceived luminance banding. There is no fundamental reason film images can't render aesthetically excellent sky regions.