Source : Webster's Revised Unabridged Dictionary (1913)

Shadowiness \Shad"ow*i*ness\, n.
   The quality or state of being shadowy.

Source : WordNet®

shadowiness
     n : relative darkness caused by light rays being intercepted by
         an opaque body; "it is much cooler in the shade";
         "there's too much shadiness to take good photographs"
         [syn: {shade}, {shadiness}]