Color Perception
Posted on 05/31/2012
Color perception by the human eye refers to wavelengths that are sensed by the rods and cones - the sensory cells of the eye. Rods are more sensitive than cones and can sense the brightness or intensity of light. However, rods cannot perceive colors. Cones are responsible for distinguishing colors based on interpreting wavelengths of light. The human retina contains more than 100 million rod cells but only about 5 million cone cells.
Light that is perceived by the human eye is a result of one of three sources: emission, transmission or reflection. Emission refers to light that originates from a chemical or physical process and is "emitted" directly from the source without an interference to the eye. Transmission refers to light that is "transmitted" through another material such a transparent (i.e. clear glass) or translucent material (i.e. stained glass). Reflection refers to light that is "reflected" off of another object - such as solid object like the lips. Both transmission and reflection also include the concept of absorption - which refers to the wavelengths that are "absorbed" by the interfering or reflecting object.
All three of these sources influence the perception of color. In dentistry, the color of the a tooth and the material best designed to achieve the designed color are affected by emission, transmission and reflection.
Portions of this post were adapted from the book:
Fundaments of Color - Shade Matching and Communication in Esthetic Dentistry published by Quintessence Publishing Co. Inc and written by Dr. Stephen J. Chu, Dr. Alessandro Devigus, Dr. Rade D. Paravina and Mr. Adam J. Mieleszko. and the Wikipedia article: http://en.wikipedia.org/wiki/Photoreceptor_cell
Light that is perceived by the human eye is a result of one of three sources: emission, transmission or reflection. Emission refers to light that originates from a chemical or physical process and is "emitted" directly from the source without an interference to the eye. Transmission refers to light that is "transmitted" through another material such a transparent (i.e. clear glass) or translucent material (i.e. stained glass). Reflection refers to light that is "reflected" off of another object - such as solid object like the lips. Both transmission and reflection also include the concept of absorption - which refers to the wavelengths that are "absorbed" by the interfering or reflecting object.
All three of these sources influence the perception of color. In dentistry, the color of the a tooth and the material best designed to achieve the designed color are affected by emission, transmission and reflection.
Portions of this post were adapted from the book:
Fundaments of Color - Shade Matching and Communication in Esthetic Dentistry published by Quintessence Publishing Co. Inc and written by Dr. Stephen J. Chu, Dr. Alessandro Devigus, Dr. Rade D. Paravina and Mr. Adam J. Mieleszko. and the Wikipedia article: http://en.wikipedia.org/wiki/Photoreceptor_cell