Basic knowledge of chromatics

Color stimulates people's feelings; It produces a contrast effect and makes the image look more beautiful. It can make a dull image bright and gorgeous, and make an originally lifeless image full of vitality. For image designers, painters, artists or video producers, it is very important to create perfect colors. Improper use of color, the concept of expression is incomplete; Images may not successfully express their information, and artistic experience will be lost. If a forest scene that should be in full of green looks yellow and sick, the importance of self-sufficiency will not be reflected, and the feeling of "health" outdoors will be lost. If the burning red light in the forest fire becomes dim, it conveys a feeling of decay and rust, not a feeling of warmth. It is not easy to create the perfect color. The painter must mix and then mix the pigments until the color is exactly the same as the color of the scene he saw or imagined. Photographers and filmmakers must spend a lot of time testing, refocusing and adding light until they create the right landscape. In many ways, using colors on a computer is no different. Computers have formed their own set of special complexities and technical difficulties. How can users ensure that the colors they see on the screen are consistent with the colors in nature or users' artistic imagination? Moreover, how can users make the color they see on the screen become the color of the printed image output? To create suitable colors in Photoshop, we must first have some knowledge of color theory. Once users understand the basic knowledge of color theory, they will know the color terms used in all dialog boxes, menus and palettes in Photoshop. When users do color correction, they will also go through the process of adding and subtracting colors. Using the knowledge of color theory, users will know how to dye the sky full and rich blue. Users will be able to choose colors, so that the emerald they created in Photoshop will appear in the forest on printed paper. In order to successfully choose the right color in Photoshop, users must first understand the color mode. Color mode is created to provide a way to convert colors into digital data, so that colors can be described continuously in various media. For example, when we mention a "blue-green", our understanding of this color depends largely on our personal feelings. On the other hand, if we assign it a unique color value in the color mode-in the CMYK mode, it is 100% cyan, 3% magenta, 30% yellow and 15% black-then it is possible to produce the same color continuously. Users will encounter several different color modes when using the color function of Phtotoshop: RGB, CMY K, HSB and Lab. RGB and CMYK color modes will make users remember natural colors forever. The colors on the user's display and the colors on the printing paper are created in a completely different way. The display produces colors by emitting red, green and blue light beams: it uses RGB (red/green/blue) color mode. In order to reproduce the continuous color effect on color photos, printing technology uses the combination of cyan, magenta, yellow and black inks to reflect and absorb various light waves. The colors created by overprinting these four colors are part of the CMYK (cyan/magenta/yellow/black) color mode. HSB (Color/Saturation/Brightness) color mode is based on the way people perceive colors, so it provides an intuitive way to convert natural colors into colors created by users' computers. Lab color mode provides a method to create "device-independent" colors, that is, no matter what kind of display 1 is used, what color is there, because there are three entities: light, watched object and observer. Physicists have proved that white light consists of three wavelengths: red, green and blue. The human eye regards colors as red, green and blue with different wavelengths absorbed or reflected by objects. For example, suppose the user took part in a field trip on a sunny day and was about to take a red apple. When the sun shines on the apple, the light with red wavelength is reflected from the apple to the user's eyes. While the green and blue wavelengths are absorbed by apples. The sensor in the user's eyes responds to the reflected light and sends out information, which is interpreted by the user's brain as red. The user's perception of red depends on the apple, the light and himself. An apple may absorb more green and blue than another apple, so its color looks redder. If the clouds cover the sun, the red color of the apple will become a little darker. Users' feelings about this apple will also be affected by their own physiological conditions, the experience of eating apples or not eating all day. Let users see that the red, green and blue wavelengths of apples are the basis of all colors in nature. This is why we often call red, green and blue the three primary colors of light. All colors in the spectrum are composed of different intensities of these three wavelengths. Overlapping the three primary colors alternately produces secondary mixed colors: cyan, magenta and yellow. Primary colors and secondary mixed colors are complementary. Complementary colors are the most different colors from each other. Yellow consists of red and green. Among them, blue is the missing primary color; So blue and yellow are complementary colors. The complementary color of green is magenta and the complementary color of red is cyan. This is why users can see other colors besides Chen Hong, green and blue. In sunflower, users see yellow because red and green wavelengths are reflected to users' eyes, while blue is absorbed by sunflower. The mixture of all primary colors forms white. Users may think that adding these colors together will produce darker colors, but don't forget that we are adding light. When we add up the wavelengths of light, we get brighter colors. This is why primary colors are usually called additive colors. Add all colors of light waves to ~, and we will get the brightest light: white light. Therefore, when we see a blank sheet of paper, all the red, green and blue wavelengths will be reflected into our eyes. When we see black, all the red, green and blue wavelengths are completely absorbed by the object, so no light is reflected into our eyes.