The histogram is a simple graph that displays where all of the brightness levels contained in the scene are found, from the darkest to the brightest. The histogram for an over exposed? photograph will show a high concentration of points cut off at the right-most (white) position. An under exposed? photograph will collect a high concentration of points at the left-most (black) position.
The values are arrayed across the bottom of the graph from left (darkest) to right (brightest). The vertical axis (the height of points on the graph) shows how much of the image is found at any particular brightness level.« Back to Glossary Index