Reflection of Light and Color

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APPLICATION OF PHYSICS & OPTICS TO GRAFT DISSECTION

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For each type of reflection, each individual ray follows the law of reflection. However, the roughness of the material means that each individual ray meets a surface which has a different orientation. The normal line at the point of incidence is different for different rays. Subsequently, when the individual rays reflect according to the law of reflection, they scatter in different directions. The result is that the rays of light are incident upon the surface in a concentrated bundle and are diffused upon reflection. The diagram below depicts this principle. Five incident rays (labeled A, B, C, D, and E) approach a surface. The normal line (approximated) at each point of incidence is shown in black and labeled with an N. In each case, the law of reflection is followed, resulting in five reflected rays (labeled A,, B,, C,, D,, and E,). This is exactly what happens with top lighting and grafts. The scatter can be most confusing to the retina, which must reassemble the data.

Reflection of Light and Color

As we have stated the retina will perceive reflected light. As you recall the visible spectrum is a narrow band between 400 and 700 nanometers. All the visible wavelengths and colors of light perceivable by the human retina exist in this spectrum. All structures either absorb or reflect specific wavelengths of light. White light consists of all individual colors or wavelengths of visible light. In surgery we typically use while light as our incident source. This means that white light consists of red, orange, yellow, green, blue, indigo, and violet or ROYGBIV for short. When you look at a specific structure, it has a color. This color is dependent on the specific wavelengths of light that it absorbs and reflects.. The structure will not appear the colors it absorbs; it will appear the color (s) it reflects. The reflected light is what your retina will see. The retina will not see the absorbed light since it will not be emitted. If a surface is capable of absorbing ROYGBIV, the surface will reflect no light and appear black. A surface that absorbs YGBIV will reflect RO and appear reddish-orange. A surface capable of absorbing ROYBIV will reflect only G and appear green. This is the principal of light reflection and color in its simplest form.