The basis of this research is the manipulation of sensor excitation values to account for differences in observer or illuminant when spectral data are unknown. This touches on several related topics: color constancy, chromatic adaptation, and white balancing. The central premise is that these concepts make use of some form of intermediate color equivalency representation or waypoint system that makes comparison and color transformations possible. Differences between these concepts are related to the kind of color equivalency representation system used and how transformations are made into and out of it. A new sensor excitation normalization method was derived that has been optimized to predict changes in material color as Wpt (pronounced Waypoint) coordinates, which can be used to form a material adjustment transform. The prediction of such changes is also known as least dissimilar color matching. This is contrasted with a chromatic adaptation transform, which is optimized to predict corresponding color changes. As such a distinction is made between adaptation (which is based on corresponding color) and adjustment (which is based on other criteria). (c) 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 535-549, 2015