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United States Department of Agriculture

Agricultural Research Service

Title: Cotton Color Measurements - the Possibility for "traceable" Hvi Color Standards

Authors
item Rodgers, James
item Thibodeaux, Devron
item Campbell, Jacqueline
item Kimmel, Linda

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2006
Publication Date: June 15, 2006
Citation: Rodgers Iii, J.E., Thibodeaux, D.P., Campbell, J.H., Kimmel, L.B. 2006. Cotton color measurements - the possibility for "traceable" hvi color standards. Proceedings of the 2006 Beltwide Cotton Conference. CD-ROM.

Interpretive Summary: The Uster High Volume Instrumentation (HVI) is used to classify U.S. cotton. Cotton color is classed by the HVI based on its Rd (diffuse reflectance) and +b (yellowness) values. Rd and +b are cotton-specific color parameters, and they are not as well known as other globally recognized color systems (e.g., L*a*b*). Further, the standards used for HVI color are ceramic tiles and cotton batts, but there is no generally recognized traceability for these standards. A joint program was implemented to investigate new standard procedures and protocols, to evaluate globally recognized color systems and their relationship(s) to Rd and +b, to investigate the possibility for “traceable” HVI color standards by the Agricultural Marketing Service (AMS), and to study the influence of various instrumental, analysis, and sampling procedures on the color results. The samples analyzed in this phase of the program were color tiles, AMS tiles, and AMS cotton batts or “bricks.” The samples were measured on both bench-top and portable instruments from various color instrument manufacturers. Overall, very good to excellent color unit agreement was observed for L*, b*, and DE* between the bench-top units for the color tiles and AMS tiles, but only fair to very-good agreement for L*, b*, and DE* was observed for the portable units. The primary variable that impacted the color agreement between units was the use of HVI glass in front of the sample. The glass impact was severe for the portable unit’s agreement results. These results indicate that the development and use of “traceable” color standards for HVI cotton color measurements is feasible. The most promising system is the use of ceramic or metal tiles on a research-grade bench-top spectrophotometer with no glass between the sample and spectrophotometer port.

Technical Abstract: The Uster High Volume Instrumentation (HVI) is used to classify U.S. cotton. Cotton color is classed by the HVI based on its Rd (diffuse reflectance) and +b (yellowness) values. Rd and +b are cotton-specific color parameters, and they are not as well known as other globally recognized color systems (e.g., L*a*b*). Further, the standards used for HVI color are ceramic tiles and cotton batts, but there is no “NIST-like” traceability for these standards. A multi-team and multi-organization program was implemented to investigate new standard procedures and protocols, to evaluate globally recognized color systems (e.g., L*a*b*) and their relationship(s) to Rd and +b, to investigate the possibility for “traceable” HVI color standards by the Agricultural Marketing Service (AMS), and to study the influence of various instrumental and sampling/procedural variabilities on the color results. The samples analyzed in this phase of the program were color tiles, AMS tiles, and AMS cotton batts. The samples were measured on both bench-top and portable instruments from various color instrument manufacturers. Overall, very good to excellent color unit agreement was observed for L*, b*, and DE* between the bench-top units for the color tiles and AMS tiles, but only fair to very-good agreement for L*, b*, and DE* was observed for the portable units. The primary variable that impacted the color agreement between units was the use of HVI glass in front of the sample. The glass impact was severe for the portable unit’s agreement results. These results indicate that the development and use of “traceable” color standards for HVI cotton color measurements is feasible. The most promising system is the use of ceramic or metal tiles on a research-grade bench-top spectrophotometer with no glass between the sample and spectrophotometer port.

Last Modified: 10/1/2014
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