Improved Spectrophotometer Fiber Sampling System for Cotton Fiber Color Measurements

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 results were encouraging, and a prototype sampling system was developed.  Protocols for pressurized fiber measurements and glass impact minimization on spectrophotometer color measurements were developed.