A novel spectral imaging technique is presented that allows multiple grayscale images to be combined in a single hardcopy print. The images are individually revealed when the print is illuminated by suitably chosen illuminants. In its basic form, the technique utilizes the complementary relation between cyan, magenta, and yellow colorants and narrow-band red, green, and blue illumination to combine and extract images. Colorant interactions are compensated through a simple calibration process. In addition, we present techniques demonstrating how gray component replacement (GCR) may be defined for illuminant multiplexed imaging and how it may be successfully exploited to allow embedding of additional patterns in the print that are revealed under uncontrolled illumination. The paper is accompanied by a light-booth based demonstration of illuminant multiplexed imaging and the effects described herein.
