The cotton length measurement from a fiber beard such as in HVI testing provides a rapid account for fiber upper half mean length and uniformity index. It will be very beneficial if more information on the entire fiber length distribution can be inferred from testing a fiber beard. The original theory of the fibrogram developed by Hertel has served as the basis of cotton length measurements from fiber beards. However, Hertel's mathematical derivation was based on a length-biased specimen, while researchers at Uster Technologies reported that HVI samples were the same as the original sample. We selected a set of cottons with wide range of fiber length to compare the length distributions from the original sample and the specimen fibers selected by the HVI fiber sampler. Since a random portion of each fiber is held by the sample holder in this method and therefore is “hidden” from the optical censor of an instrument, efforts were made to reduce the fiber portion hidden in the sample holder in order to improve the accuracy of length measurement. Preliminary results on this study will be presented.