| Each individual wavelength within the spectrum of visible light wavelengths is representative of a particular color. That is, when light of that particular wavelength strikes the retina of our eye, we perceive that specific color sensation. Isaac Newton showed that light shining through a prism will be separated into its different wavelengths and will thus show the various colors that visible light is comprised of. The separation of visible light into its different colors is known as dispersion. Each color is characteristic of a distinct wavelength; and different wavelengths of light waves will bend varying amounts upon passage through a prism; for these reasons, visible light is dispersed upon passage through a prism. Dispersion of visible light produces the colors red (R), orange (O), yellow (Y), green (G), blue (B), indigo (I), and violet (V). It is because of this that visible light is sometimes referred to as ROY G. BIV. The red wavelengths of light are the longer wavelengths and the violet wavelengths of light are the shorter wavelengths. Between red and violet, there is a continuous range or spectrum of wavelengths. The visible light spectrum is shown in the diagram below. Hairs either make pigment or they do not make pigment. Hence, we often state that a person has a particular color of hair- blonde, brunette, red-head, black hair, etc. We mistakenly sate that many individuals have grey hair. This is not true. In fact grey hair, which results from an imperfect absorption of light, is quite rare. As hairs age, they generally loose the ability to make pigment. These hairs take on a white color, as a result. White hair results from a complete reflection of all colors of light. This results in a significant problem in hair restoration surgery. In the following photograph you see one pigmented hair and one white hair. The dissection of grafts in patients suffering form hair loss is a difficult process. This process is complicated significantly if the hairs lack pigment. While the hairs appear white above the surface of the skin, they take on a clear or translucent appearance within the skin. As such they can be very difficult to see during the graft dissection process in hair transplant surgery. In fact, it can be almost impossible to see the hairs.  This has led to a number of efforts to improve the visualization of white hairs. Numerous physicians have tried various hair dyes without significant success. Sharon Keene, MD tried tissue dyes with mixed results. She found that the dyes were not able to penetrate the deeper layers or through the surface of the skin. She postulated that applying a liposome to the tissue dye might assist in this penetration. A liposome is a vehicle for transporting an agent or medication through the skin surface to the tissue. Thus far this effort has been unsuccessful, but does hold promise. The dye and the liposome will need to pass strict FDA approval, however, and this might prove difficult. Both the dye and the liposome might prove harmful the human body, cause secondary medical problems, or induce an allergic response. Their application is unlikely. | 
