quadtone

English

Etymology

quad- +‎ tone

Noun

quadtone (plural quadtones)

1. (music) An interval of four whole tones.
2. A picture printed in four shades.
   • 1995, Adele Droblas Greenberg, Seth Greenberg, “Converting from One Mode to Another”, in Fundamental Photoshop, 2nd edition, Osborne McGraw-Hill, →ISBN, page 380:

     In Photoshop’s Duotone mode you can create monotones, duotones, tritones, and quadtones—grayscale images to which you add one, two, three, or four colors.

   • 2003, Duncan Evans, “Duotones and Tritones”, in A Comprehensive Guide to Digital Portrait Photography, AVA Publishing SA, →ISBN, page 115:

     When using tritones or quadtones (in which three colours are blended together) all the secondary colours are mixed together.

   • 2010, David Präkel, “Duotone”, in The Visual Dictionary of Photography, AVA Publishing SA, →ISBN, page 97:

     The two colours need not be black and grey; computer duotones can be created from a greyscale original in any two colours; tritones use three inks and quadtones four.