*Histogram is a map of pixels on a scalefrom pure black to pure white.*Shows the brightness/darkness of eachpixel represented on this scale and howmany of these pixels are in each zone.*Left represents the black/Dark end. Rightrepresents the white/Bright end and themiddle is perfect middle Gray.
It acts as a graphical representation of the tonal distribution in a digital image. It plots the number of pixels for each tonal value.By looking at the histogram for a specificimage a viewer will be able to judge the entire tonal distribution at a glance.