The Histogram Tool (Ctrl+H) displays distribution of pixels at each
level of basic colors (red, green and blue) intensity. This graph can be used to reveal under- or overexposed photographs.
It can also be used to verify white balance. If photograph contains known white areas they can be examined
separately by selecting rectangle to sample. Overlapping Red, Green and Blue curves indicate perfect gray.
Shifted curves reveal color tinting.
To calculate histogram for a part of an image one can draw a selection rectangle. Histogram will then show
distribution of colors in the selected image fragment.
Histogram area is subdivided into five intensity zones: from the darkest to the brightest.
Note: histogram tool operates on the current photograph and uses its scaled down version to calculate graphs.
