How the Chromatic Adaptation Calculator Works

This calculator is useful for adapting a color from one reference white to another. While chromatic adaptation is always performed in XYZ, this calculator has implemented other common CIE color models as a convenience to the user. The calculator adapts a Source Color into a Destination Color. The internal working of the calculator is illustrated here:

To use the calculator, first set up the source and destination color models you wish to use and their respective reference whites. Then enter a source color (in the color model you have selected for the source) and click the "Calculate" button. The adapted color is displayed in the color model you have selected for the destination.

By selecting different Adaptation Methods, you can compare how each performs. It is generally accepted that Bradford is superior to von Kries, which in turn is superior to XYZ Scaling. If you are interested in the mathematics behind chromatic adaptation, you will find the equations here. There is also an evaluation study of the various adaptation algorithms here.

The display is automatically updated as you change the adaptation method, the destination color model and the source and destination reference white. If you change the source color model or the source color, you must click the "Calculate" button to update the display.

Some interesting observations:

1. All three adaptation methods perform identically on neutral source colors. The differences are more pronounced as the source color becomes more chromatic.
2. If the source and destination reference whites are the same as each other, then no adaptation occurs, and therefore all methods produce identical results for all colors.
3. With XYZ Scaling, the Lab and LCH(ab) colors will always be identical between the source and destination. This results from the simplicity of this particular adaptation model.
4. Some colors, after passing through a chromatic adaptation, can become "illegal," for example, one or more of their XYZ components may become negative. If this occurs, the destination color components will not be displayed.