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United States Department of Agriculture

Agricultural Research Service

Title: Impacts of Glass Use in Cotton Color Measurements

Authors
item Rodgers, James
item Kang, Sho Yeung - UNIV OF GEORGIA
item Cui, Xiaoliang
item Martin, Vikki - COTTON INCORPORATED
item Watson, Mike - COTTON INCORPORATED

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2008
Publication Date: April 25, 2008
Citation: Rodgers III, J.E., Kang, S., Cui, X., Martin, V., Watson, M. 2008. Impacts of glass use in cotton color measurements. Proceedings of National Cotton Council Beltwide Cotton Conferences. p. 1504-1510.

Interpretive Summary: Cotton color is an important quality property that is used to “class” cotton fiber. In the U.S., cotton is classified for color using the Uster® High Volume Instrument (HVI). The color of cotton on the HVI is denoted by the parameters Rd and +b, which represent the cotton’s diffuse reflectance and yellowness, respectively. Rd and +b are specific to cotton fiber and are not typical globally recognized color systems. An earlier program established and validated the feasibility of correlating Rd and +b to the globally recognized color system L*a*b* for both standard tiles and cottons. The major impact on agreement between the HVI and standard color spectrophotometers and between color spectrophotometers was the use of glass (required for cotton color analyses) between the sample and the spectrophotometer measurement port. A program was implemented to determine ways to minimize the glass impact. The glass impact of the 6 mm thick HVI glass on color results was significantly greater than that of the 1 mm thick microscope slide. Protocols for minimizing glass impacts on spectrophotometer color measurements were determined, with the best overall results obtained with the use of the color instrument setting of specular component included (SCI) and with the use of “glass with glass calibration” conditions.

Technical Abstract: Cotton color is an important classification property. In the U.S., cotton is classified for color using the Uster® High Volume Instrument (HVI). The color of cotton on the HVI is denoted by the parameters Rd and +b, which represent the cotton’s diffuse reflectance and yellowness, respectively. Rd and +b are specific to cotton fiber and are not typical globally recognized color systems. An earlier program established and validated the feasibility of correlating Rd and +b to the globally recognized color system L*a*b* for both standard tiles and cottons. The major impact on agreement between the HVI and standard color spectrophotometers and between color spectrophotometers was the use of glass (required for cotton color analyses) between the sample and the spectrophotometer measurement port. A program was implemented to 1) investigate the impact of glass and glass type on the spectrophotometer color measurements and 2) to determine the feasibility of minimizing the glass impact. The glass impact on spectrophotometer color results was much greater than that of specular component type. The glass impact of the 6 mm thick HVI glass on color results was significantly greater than that of the 1 mm thick microscope slide. Protocols for minimizing glass impacts on spectrophotometer color measurements were determined, with the best overall results obtained with the use of specular component included (SCI) and glass with glass calibration.

Last Modified: 12/22/2014
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