A full scale RGB book valued at $3 million
Tauba Auerbach presents the RGB color scheme in a hard-copy reference volume of all the colours in existence. We estimate, with ink around $40 for a printer cartridge, that this would have cost around $3 million to print. Give or take. You can see a small number of them at the Museum of Modern Art in NYC.
(Update: We hear this is the CMYK colour spectrum. If you know what we mean?)