Chapter 9 323 instrumental techniques.52-54 Mostly, these studies are concerned with measuring hair dye deposition,53 or dye fastness due to exposure to UV light52 or shampooing.54 Several published studies utilized diffuse reflectance spectrophotometry to examine hair with regard to luster measurements27 or to explore changes in the near IR region induced by physical stresses.55 In addition, there is an account in the literature comparing tri-stimulus measurements with spectrophotometry for the determination of hair color.56 Imaging techniques: As stated above, color measurements were traditionally carried out utilizing a reflective spectrophotometer or tri-stimulus colorimeter. In the last two decades, digital imaging devices, such as DSLR cameras and flatbed scanners, have become increasingly more sophisticated and available at economically feasible prices. Most manufacturers of spectrophotometers would warn against using such devices to conduct color measurements however, there are instances when digital imaging devices are more suitable than large, benchtop instruments. Forensic scientists and anthropologists have great interest in the ability to use digital photography to measure color differences in hair. With the growing use of surveillance video recording devices, the forensic scientist would like to quickly identify individuals based on recognition of hair pigmentation differences. Likewise, anthropologists seek portable devices to carry with them in the field to take measurements leading to information about biological traits of societies, including their ancestry.56 For these reasons, recent studies comparing color measurements obtained by more established techniques such as spectrophotometry with digital photography have appeared in the literature.57-59 In cosmetic science, we can benefit greatly from the ability to carry out measurements of hair pigmentation utilizing digital photography and image analysis. Hair color changes may occur as a result of environmental insult, such as photo- or thermal degradation of hair, which usually results in the formation of yellow and brown chromophores inside the fiber structure. The less pigmented the original hair fiber, the more noticeable such