Exercise: Sensor Linear Capture
Take any .jpeg image into Photoshop and convert it to 16 bits per channel because you will be making some strong adjustments that might create banding in regular 8-bit. Using Curves, create a curve that looks similar to the ante-gamma correction curve shown in the course manual. Save this much darker image, with a different file name and open the original again at the same time as this darker image. Click from one to the other with the histograms open and see how they differ.
It’s now clear why noise is mostly confined to the shadow/dark areas of an image and also the losses associated with .jpeg images, as witnessed by the transformation from initial .jpeg to Gamma Corrected Image where the banding occurs. Some of this banding must be due to data loss in the constant transformations.