We know the image has very few pure white areas, a bunch of pure black areas, and is mostly composed of tones in the lower quartertones.
That's either a reasonably exposed low-key image, an underexposed medium-key image, or is a very undererexposed high-key image.
(The last is unlikely, as there are some pure white areas, so unless there's a lot of specular highlights, it's highly unlikely to be intended as a high-key image.)
From the shape of the R, G, and B histograms, we can tell that there are large areas of dark neutral colors.
We still don't know if it's properly exposed from the histogram alone.
From the histogram and the image, we can say it's probably properly exposed
©2008 Kevin Connery
July 1, 2008