Basic knowledge about color of different types of substances
1. Color of achromatic objects
Achromatic objects refer to black, white, and gray objects. They have non-selective absorption characteristics of illumination light. That is, when light shines on an achromatic object, the absorbed incident light The various wavelengths of colored light are equal in amount; the spectral components of the reflected or transmitted light are also the same as the spectral components of the incident light. When white light shines on an achromatic object, if the reflectivity is above the first 75%, it will appear white; if the reflectivity is below 10%, it will appear black; if the reflectivity is between the two, it will appear different shades of gray.
2. Color of colored objects
Colored objects have the characteristic of selectively absorbing illumination light. That is, when light shines on a colored object, the colored lights of various wavelengths absorbed in the incident light are not equal in amount, and some are absorbed by multiple wavelengths. Absorbed, some are less absorbed. When white light shines on a colored object, the reflected or transmitted light not only weakens in brightness but also changes in spectral composition compared with the incident light, thus showing various colors.
3. The influence of the spectral component of the light source on the color of the object
When colored light shines on an achromatic object, the color of the reflected light from the object is the same as the color of the incident light. When two or more colored lights illuminate an achromatic object at the same time, the color of the object shows an additive color effect. If red light and green light illuminate a white object at the same time, the object will appear yellow.
When colored light shines on a colored object, the color of the object shows a subtractive color effect. Anyway, just as a yellow object appears red when illuminated by magenta light, green when illuminated by cyan light, and gray or black when illuminated by blue light.
4. The relationship between the color of an object and light
Does not emit light Color (non-self-luminous colour)
The color produced by an object through illumination is a non-luminous color, such as the color of color chips, paints, fabrics, etc. </p
