Histogram

A histogram is a graphical representation of all the tones of an image. The purpose of a histogram is to evaluate an image.   A good histogram should have smooth hills and slope down at both ends.

Examples of Poor Histograms

Clipping- spikes in shadow or highlight from extreme contrast

(Highlight and shadow detail will be lost, rescan)

Combing or Gapping – Spikes throughout the image

(Banding will occur, rescan)

Spaces in shadow or highlight- extremely flat image

(Will cause combing when corrected, rescan)