Full color printing started with cyan, magenta, and yellow. Then black was added to extend the gamut down in the shadows. Later spot colors were added to make the gamut wider (Hexachrome, Indichrome, etc.). Now Romain Rossier & Roger David Hersch are adding light fluorescent magenta and yellow to extend the gamut up in the light colors. They are presenting their work at the CIC 20th Conference in Hollywood in the Friday afternoon session on Printing chaired by Jan Allebach. Of course, the slides are limited by the projector's gamut, so you need to be there and look at the actual prints.