Nokia Amber
AllaboutWindowsPhone has examined the improvements in image quality promised by the new Nokia Black image processing algorithms using a Nokia Lumia 1020.
Nokia Black
As can be seen from the example above the colour accuracy has been significantly improved and is now much more natural, without the yellow cast which is present in so many Lumia pictures.
Nokia Amber Nokia Black
Images also show much improved noise reduction while preserving detail.
AAWP concludes:
The Nokia Black update, as far as I can see, takes the Lumia 1020 camera to the next level again and will further distance it from any competition. Less noise, more accurate colours, purer photos and smaller file sizes all mean that the best just got better.
See many more comparison shots and more detail at AAWP here.