Investigation Of The Relationship Between Spectral Smoothness And Color Constancy

When a spot color ink is initially formulated, the ink technician needs to decide between many potential combinations of base inks that could yield the desired color under the desired illuminant. One of the primary criteria for selection is to restrict the number of base inks that are used. A second criterion which is commonly used is the metameric index. This is the color difference as computed between the spectrum of the target color and predicted spectrum of the recipe under consideration. A third potential criterion is color constancy – the formulation should, as much as possible, maintain its appearance under different illuminants. This criterion is never used, at least in part because we don’t know how to measure it!

This paper considers a few possible metrics for color constancy, specifically at whether a smooth spectrum is an indicator of a spectrum that will prove to be more color constant.