Sensor linear capture.

Exercise: Sensor linear capture.

Original.

As taken by sensor.

Recovered by use of Curves.

The histogram for the first shot is fairly even and there are indications of lost shadow areas as it is pushed up against the left edge.  The clip warning confirmed this.  This is what I would expect of  a shot like this with even colours, a few highlights, and a lot of dark areas.

The second histogram was as the text described and pushed hard up against the left edge.  

The third histogram has a strange fractured look and, although the image looks very similar to the original, this histogram shows that changes have taken place.  I could not detect any additional noise in this recovered version.