Source : Webster's Revised Unabridged Dictionary (1913)

Yellow \Yel"low\, v. t. [imp. & p. p. {Yellowed}; p. pr. & vb.
   n. {Yellowing}.]
   To make yellow; to cause to have a yellow tinge or color; to
   dye yellow.

Source : WordNet®

yellowed
     adj : changed to a yellowish color by age; "yellowed parchment"
           [syn: {yellow}]