The Uster® High Volume Instrument (HVI) is used to class U.S. cotton for fiber color, yielding the cotton-specific color parameters Rd and +b. The HVI examines a nine-square-inch fiber sample, such as the large AMS standard cotton "biscuits" or rectangles. Much interest has been shown in measuring cotton color on modern color spectrophotometers and on relating the HVI Rd and +b color parameters to more globally recognized, three-dimensional color space systems obtained from spectrophotometers, such as L*a*b*. Recent research established the relationships of Rd and +b to L* and b*. However, concerns have been expressed on the consistency of fiber measurements on large area cotton fibers with spectrophotometers. When fiber is measured on color spectrophotometers, hand pressure by an operator is often used to hold the fiber against the spectrophotometer sampling port for the measurement, but the pressure applied varies from operator to operator and from sample to sample. The need exists for a spectrophotometer fiber sampling system for large area fiber samples that allows for the application of uniform pressure to large cotton fiber samples. A program was implemented to develop a pressurized fiber sampling system for color measurements with large cotton fiber samples (e.g., AMS standard cotton biscuits). A sampling system for large cotton fiber samples was developed for spectrophotometers in which a uniform pressure is applied across the entire sample surface area. The color parameter most impacted by fiber pressure was L*. Protocols were developed for pressurized cotton fiber color measurements on spectrophotometers.
