Un-dyed
wool fabric had a much more yellow (+b*) appearance, slightly greener (-a*) appearance, and
higher initial K/S than un-dyed cotton fabric. Wool's slight coloration is typical because the only
treatment done to the wool used in this work was carbonization. Carbonization only removes
organic matter that may have been trapped in the fibers during production (Halliday, 2002), so
some natural color was still present.