Calculating Gardner Color Numbers from Modern Color Software Chromaticity Values

Although somewhat dated, Gardner color numbers are still very much a part of established analytical procedures used in the US to evaluate the color of a variety of samples. Modern color software can provide more accurate color analysis using color scales such as CIE XYZ, CIE Lab, or chromaticity. However, the Gardner scale is well-established in certain industries and still widely utilized; consequently, it is occasioned that results from a Modern Color Scale be converted to equivalent Gardner numbers.

The Shimadzu Color Software allows the selection of a variety of Color Scales including CIE XYZ, CIE Lab, and Chromaticity. In addition, various other parameters such as the dominant wavelength (dWL) can be selected. For Gardner analysis by ASTM D6166, the Chromaticity parameters, x and y, are required for the conversion calculations.