1) Two-color print 
• (n.) A print made from two half-tone plates made from the same negative, but etched differently.
Du'o·type noun [ Latin duo two + type .] (Photoengraving) A print made from two half- tone plates made from the same negative, but etched differently. 
two halftone plates made from a monochrome original but etched differently to create two values of intensity when superimposed in printing.