Highest Quality Capture: Workflow Phase I - Black and White in Photoshop CS4 and Photoshop Lightroom - page 39

can record and is a function of both the subject luminance
range and the characteristic curve of the i lm or sensor.
Zone 0 = Pure black
Zone I = Slight tonality, without texture
Zone II = Black with i rst suggestion of tonality
Zone III = Average dark, low values showing adequate texture
Zone IV = Average shadows
Zone V = Middle gray, 18% gray card
Zone VI = Shadows on snow in a sunlit snow scene
Zone VII = Lightest areas in a scene that retain some visible detail
Zone VIII = White areas with slightly visible texture
Zone VIX = Glaring white surfaces, highlights without texture
Zone X = Paper white, white with no detail, a lightsource
So what do all these numbers and values mean in the i eld?
Plain and simply put - exposure. Camera meters are designed with the
assumption that all scenes have the same average middle gray tonal value,
roughly Zone 5. If a scene is dif erent, for example a snow scene as pictured
below, the camera by itself will tend to expose incorrectly, wanting to portray
the white in a scene as gray values. The white snow will read to the meter as a
middle gray and ultimately result as an underexposed capture by meter alone.