COTTON COLOR MEASUREMENTS BY AN IMAGING COLORIMETER

Color grade is one of the major components of the current cotton classing system. This paper presents the application of an imaging colorimeter to color measurements of the USDA standards for U.S. Upland cotton and cotton samples with a wide range of colors. Tests on the reproducibility and spatial uniformity of the color imeter's data are reported, and the results are directly compared with results from other colorimeters and human classers. Methods for creating new color grade dia grams in the CIE L*a*b* system are explained. A new concept suggests using primary and secondary color grades for cotton samples. These two grades can be determined from the L*∼b* and L*∼a* diagrams created by the imaging color imeter. The secondary grade, using the red-green attribute, can help reduce the uncertainty of color grading when the color measurements are near a boundary between two grades in one color diagram.