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United States Department of Agriculture

Agricultural Research Service

Title: Improved Spectrophotometer Fiber Sampling System for Cotton Fiber Color Measurements

Authors
item Rodgers, James
item Elkholy, Karim
item Cui, Xiaoliang
item Martin, Vikki - COTTON INCORPORATED
item Watson, Michael - COTTON INCORPORATED

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: February 5, 2009
Publication Date: April 23, 2009
Citation: Rodgers III, J.E., Elkholy, K.N., Cui, X., Martin, V., Watson, M. 2009. IMPROVED SPECTROPHOTOMETER FIBER SAMPLING SYSTEM FOR COTTON FIBER COLOR MEASUREMENTS. Proceeding of the National Cotton Council Beltwide Cotton Conference. 1199-1204 CD-ROM.

Interpretive Summary: Cotton in the U.S. is classified for color using the Uster® High Volume Instrument (HVI), and the parameters Rd and +b are used to designate color grades for cotton fiber. However, Rd and +b are cotton-specific color parameters, and the need existed to demonstrate the relationships of Rd and +b (HVI) to L*a*b* (color spectrophotometers) if standards are to be developed for cotton color measurements. A program was implemented to determine the impact of applied pressure on spectrophotometer fiber measurements and to develop an improved, pressurized fiber sampling system that can precisely measure large cotton fiber samples (e.g., standard AMS bricks). The pressure impact results indicated that applied pressure impacted primarily fiber L*. The optimum applied pressure for fiber color measurements was 30 psig (pounds per square inch gauge). For large fiber samples (e.g., Agricultural Marketing Service/AMS cotton bricks), a prototype sampling system was developed. Protocols for pressurized fiber measurements on spectrophotometer color measurements were developed.

Technical Abstract: Cotton in the U.S. is classified for color using the Uster® High Volume Instrument (HVI), and the parameters Rd and +b are used to designate color grades for cotton fiber. However, Rd and +b are cotton-specific color parameters, and the need existed to demonstrate the relationships of Rd and +b to L*a*b* if “standards” are to be developed for cotton color measurements. The relationships of Rd and +b from the HVI to the globally recognized L*a*b* color system from color spectrophotometers was verified and validated previously. A program was implemented to 1) determine the impact of applied pressure on spectrophotometer fiber measurements and 2) to develop an improved, pressurized fiber sampling system that can precisely measure large cotton fiber samples (e.g., standard AMS bricks). The pressure impact results on small fiber “fluff” samples indicated that applied pressure impacted primarily fiber L*. The optimum applied pressure for small “fluff” fiber color measurements was 30 psig (pounds per square inch gauge). For large fiber samples (e.g., Agricultural Marketing Service/AMS cotton bricks), a prototype sampling system was developed. Protocols for pressurized fiber measurements on spectrophotometer color measurements were developed.

Last Modified: 10/30/2014
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