COTTON COLOR MEASUREMENTS BY AN IMAGING COLORIMETER

Color grade is one of the major components of the current cotton class ing system. This paper presents the application of an imaging colorime ter to color measurements of the USDA standards for U.S. Upland cotton and cotton samples with a wide range of colors. Tests on the reproduc ibility and spatial uniformity of the colorimeter's data are reported, and the results are directly compared with results from other colorim eters and human classers. Methods for creating new color grade diagram s in the CIE La*b* system are explained. A new concept suggests using primary and secondary color grades for cotton samples. These two grad es can be determined from the Lsimilar to b* and L*similar to a* diag rams created by the imaging colorimeter. The secondary grade, using th e red-green attribute, can help reduce the uncertainty of color gradin g when the color measurements are near a boundary between two grades i n one color diagram.