资料来源 : pyDict

双色的;两色网版的一种

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Duotone \Du"o*tone\, n. [L. duo two + tone.] (Photoengraving)
   Any picture printed in two shades of the same color, as
   duotypes and duographs are usually printed.