Light is an electromagnetic wave in physics. Only electromagnetic waves with wavelengths ranging from 0.39 micrometers to 0.77 micrometers can evoke people's visual perception of color. This range is called the visible spectrum. Wavelengths greater than 0.77 micrometers are called infrared rays, and wavelengths less than 0.39 micrometers are called ultraviolet rays.
Light and color coexist; only with light can there be color. The perception of color cannot do without light.
Light and the Visible Spectrum. Light is an electromagnetic wave in physics. Only electromagnetic waves with wavelengths ranging from 0.39 micrometers to 0.77 micrometers can evoke people's visual perception of color. This range is called the visible spectrum. Wavelengths greater than 0.77 micrometers are called infrared rays, and wavelengths less than 0.39 micrometers are called ultraviolet rays.
(2) Propagation of light. Light travels in a straight line in the form of waves and is influenced by two factors: wavelength and amplitude. Different wavelengths produce differences in hue. Different amplitudes of strength produce variations in the brightness and darkness of the same hue. Light has various forms of propagation, such as direct irradiation, reflection, transmission, diffusion and refraction. When light shines directly into the human eye, what is perceived visually is the color of the light source.
When a light source shines on an object, the light is reflected from its surface, and what the human eye perceives is the color of the object's surface. When light shines on transparent objects such as glass, what the human eye sees is the penetrating color of the object. When light propagates and is interfered with by an object, it undergoes diffusion, which has a certain impact on the surface color of the object. If the direction changes when passing through different objects, it is called refraction, and the color of the light reflected to the human eye is the same as that of the object.
2. Object color
Objects in nature are diverse and ever-changing. Although most of them do not emit light themselves, they all have the characteristic of selectively absorbing, reflecting and transmitting colored light. Of course, no object can absorb or reflect all the colored light. Therefore, in reality, there is no absolute black or white.
Among the common black, white and gray object colors, the reflectivity of white is 64% - 92.3%. The reflectivity of grey is 10% - 64%. The absorption rate of black is over 90%. The ability of an object to absorb, reflect or transmit colored light is greatly influenced by the texture state of its surface. Objects with smooth, flat and fine surfaces have a stronger ability to reflect colored light, such as mirrors, polished stone surfaces and silk fabrics. Objects with rough, uneven or loose surfaces tend to cause light to diffuse, thus having a relatively weak reflection of colored light, such as frosted glass, woolen fabric and sponge.
However, some technicians believe that an object's ability to absorb and reflect colored light is fixed, and the surface color of the object will change with the color of the light source, sometimes even losing its original hue perception. The so-called "inherent color" of an object is actually just a habit people have of it under normal light. Under the flickering and intense neon lights of various colors, the costumes of all the buildings and figures almost lose their original colors and appear strange and unpredictable. In addition, the intensity and Angle of light also have an impact on the color of objects.
