The Technology of Duotone Color Transformations in a Color Managed Workflow

Duotone refers to an image with various shades of a hue mapped in an vector or wedge through a color space. The colorant, the gradient curve, and the number of colorants used define the slice through the color space. The image is printed with two or more analogue colorants. The colorants may be custom formulated or selected from a named color system. Typically two colorants are placed on a substrate by a halftone procedure, and the visual result, the mixture of the two colorants, is a third color. A gamut map of the colorants requires an accurate model of the thrid color that results from halftoning and printing the two inks. Color management procedures convert this gamut model to a vector through a monitor RGB color space and then to CMYK for proofing. This paper describes such a color management procedure