What is a “histogram” and what does it show us?
A histogram is simply a vertical bar-chart. It charts the brightness (luminosity) of a given picture. The software used to generate the chart is looking at each individual pixel (dot) in the picture and counts how many are black, white or various shades of gray. The bar chart runs from pure black on the left (luminosity value = 0) to pure white (luminosity value = 255) on the right. The more pixels that have a specific luminosity, the larger the “hump” at that position in the chart. This is not the colors of the rainbow. This is from black through lightening shades of gray to white. Unfortunately, there is no such thing as a perfect histogram. Each histogram is as unique as the photograph from which it is generated. Generic shots at a baseball game, crowd shots, shots of the forest along a lake with the mountains and sky in the far background tend to have histograms that stretch from one side to the other. A shot where a red rose takes up 90% of the image will have a much narrower hist
