Colorants
Pages 7-13
DOI: https://doi.org/10.1094/1891127004.002
ISBN: 1-891127-00-4
Abstract
Topics Covered
- Physiological Basis of Color
- Visual Systems
- Spectrophotometric Measurement of Color
- Tristimulus Colorimetry
- Specialized Colorimeters
Introduction to Chapter
The appreciation of color involves an effect on the human brain via a signal from the eyes. It should not be surprising to learn that a large body of science has evolved around the physiology of vision and the interpretation of visual signals from the human brain. Vision seems to be the top intelligence gatherer, since nearly one quarter of the brain's cerebral cortex is devoted to sight, much more than is devoted to the other senses.
The color of a food is not a physical characteristic such as particle size, melting point, or specific gravity. Rather it is one portion of the input signals to the human brain and results in the perception of one aspect of the food's appearance. Appearance may be influenced by a number of physical characteristics, such as particle size or texture, and a series of psychological perceptions, such as background color or arrangement in space. The human eye is a very sensitive organ — it can detect up to 10,000,000 different colors. Color as seen by the human eye is an interpretation by the brain of the character of light being reflected from or transmitted through an object. It is possible to define a food's color in a purely physical sense in terms of the physical attributes of the food, but this approach has serious limitations when we try to use color measurement as a quality control tool for food processing and merchandising. A more satisfying approach is to define color in a physical sense as objectively as possible and interpret the output in terms of how the human eye sees color.
