duotone
/ˈdjuːətəʊn/noun
1- a half-tone illustration made from a single original with two different colours at different screen angles双色版插图, 双色图片。
1.1
- mass noun the technique or process of making such illustrations双色版印刷技术（或过程）：
the best images that duotone can produce.
双色版印刷术所能印制的最好图像。