Light and color of printed color chart

Light and color coexist, only light is colored. Color feels inseparable from light.
(1) Light and visible spectrum. Light is a kind of electromagnetic wave in physics. Electromagnetic waves from wavelengths of 0.39 to 0.77 micron can cause people's visual perception of color. This range is called the visible spectrum. Wavelengths greater than 0.77 microns are called infrared rays, and wavelengths less than 0.39 are called ultraviolet rays.
(2) The spread of light. Light travels in straight lines in the form of undulations, with both wavelength and amplitude. Different wavelengths produce hue differences. Different magnitudes of amplitude produce differences in lightness and darkness of the same hue. Light is transmitted in direct, reflective, transmissive, diffuse, refractive and other forms. Directly into the human eye when the light is direct, the light source is the light source.
When the light source illuminates the object, the light is reflected from the surface of the object. What the human eye feels is the surface color of the object. When the light is irradiated, in the case of a transparent object such as glass, the human eye sees through the object through the color. In the process of propagation, when the object is interfered with by light, diffusion occurs, which has a certain influence on the surface color of the object. If there is a change in direction when passing through different objects, this is called refraction. The color of light reflected by the human eye is the same as the color of the object.
2. Object-colored objects are numerous and varied. Although most of them don't emit light, they all have the characteristic of selectively absorbing, reflecting, and transmitting colored light. Of course, it is not possible for any object to absorb or reflect all of the colored light, and therefore, there is virtually no absolute black or white.
In the common black, white and gray object colors, the reflectance of white is 64%-92.3%; the reflectance of gray is 10%-64%; the absorption rate of black is more than 90%. The ability of an object to absorb, reflect, or transmit colored light is greatly affected by the texture of the surface of the object. Smooth, flat, delicate objects have strong reflections of colored light, such as mirrors, polished stone surfaces, and silk fabrics. Rough surface, uneven, loose objects, easy to make light diffusion phenomenon, so the reflection of the light is weak, such as frosted glass, wool, sponge and so on.
However, the absorption and reflection ability of the object to the color light is fixed, but the surface color of the object changes with the color of the light source, and sometimes even loses its original hue feeling. The so-called "intrinsic color" of objects is actually just people's habits under normal light. For example, under the twinkling, intense neon light, the colors of all buildings and characters almost lost their original colors and became unpredictable. In addition, the intensity and angle of illumination also affect the color of the object.