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If you ask everyone what the three primary colors are, some people may say "it's not red, yellow and blue!", and some people may say "yes, I know, the three primary colors are red, green and blue", then which is correct? ? In fact, nothing is wrong. The three primary colors of color in art are red, yellow, and blue, while the three primary colors of light are red, green, and blue. The three primary colors in printing are cyan, yellow, and yellow. So why are these three primary colors not the same? Sometimes we will find that the color of the photos will feel reduced by one order when they are washed out. In fact, there is a certain scientific reason in it. The following will explain to you.
Let me tell you about the color of light first, because what the human eye can perceive is the color of light. We may have learned in the physics textbooks of junior high school and elementary school that white light can be decomposed into three kinds of light, red, green and blue by a prism. If you look closely at the TV or computer screen, you will find transistors of three colors of red, green and blue, which means that almost all colors of light can be combined with these three lights, so the three primary colors of light are red (R) green (G). ) Blue (B), which is what we often call RGB mode, the value of each letter R, G, B in the RGB mode represents the intensity of these three types of light, each ranging from 0 to 255, Let's think about it, if the value of RGB is (0,0,0), what color do we see? I think everyone should be able to figure out that it is black. If RGB is 0, it is equivalent to a room without light, so it is black. What if the value of RGB is (255, 255, 255)? Yes, it is a beam of white light. What if the RGB values are (128, 128, 128)? It should be gray. Let me talk about it here. If the values of the three RGB lights are the same, there is no hue. As for the hue, there is a lot of content. You can go to Baidu. What if the value of RGB is (255,0,0)? Well, it's a big red light.
I believe that everyone should have a certain preliminary understanding of light, so ask, if a red light and a green light shine on a white wall, what color should the wall appear? Red? green? Purple? blue? . . . Yellow will appear, so yellow light does not contain blue light, so it can be said that yellow is the complementary color of blue. You can look at the picture below. The two opposite colors are complementary colors. The combination of two complementary colors will produce black, the combination of two complementary colors will produce white light, and the combination of other colors will produce intermediate colors, such as the combination of red and green. will produce yellow.
In fact, the color is really amazing. I will continue to ask everyone, in a pure black room, if there is a cyan wall and we use green lights to illuminate it, what color should it be? It should be green, what if I use blue light to take pictures? The wall will appear blue, so what if you use red light to illuminate it? Will the wall appear red? I can tell everyone that the walls will turn black and nothing can be seen. If it feels incredible and you are curious, you can try it. It is really amazing, because the walls of cyan are all absorbed by red, because cyan and red are complementary colors, that is, cyan does not contain red , but cyan and red When light is combined, it produces white light, which is why the three primary colors of light are different from the three primary colors of object colors. So why does green light see green light on a cyan wall, but not any other color? Because the cyan color contains pure green color, it will reflect all the green light, so we will see the green color.
那么我们看一下印刷的三原色，也就是青(C)品(M)黄(Y)，但是CMY和RGB是不同的，CMY的值是按0%到100%来计算的，也就是我们印刷油墨的浓度，如果CMY的值都为0%，那应该是什么颜色呢？毫无疑问，一张白纸上啥都不印，当然是白色了，如果CMY的值都为100%呢？是很么颜色？黑色吗？理论上是的，但是真正情况下是无法达到黑色的，因为我们的工艺无法达到三种纯正三原色的染料，那黑色怎么办呢？我们工业上会有纯黑色的染料，所以我们印刷的模式基本称作CMYK模式，所以我问下大家，我们的一张彩色印刷的图片上的黑颜色的CMYK的值都是多少呢？(100%,100%,100%,100%)？错！ 是(0%，0%，0%，100%)，那么印刷三原色和光的三原色有什么关系呢，我们看下上面的图片，青品黄正好是红绿蓝的补色！难道仅仅是巧合吗，不是的，我们可以发现，青色染料和黄色染料混合会产生绿色，青色染料和品红色染料混合会产生蓝色，品红色染料和黄色染料结合会产生红色，所以染料的三种颜色几乎可以表示出自然界的物体所有颜色，而光的三原色几乎可以表示出光的所有颜色，所以是不是感觉很神奇？染料三原色全为0%时是白色，所以染料的三原色适用减色法，光的三原色全为255时为白光，所以光的三原色适用加色法。
光能表示的颜色范围和染料能表示的颜色范围虽然有很多的交集，但大家必须清楚，我们会发现显示器上有很多的颜色印刷不出来，因为光能表示的范围和染料表示的范围是不同的，比如说屏幕上一个非常非常亮的特别鲜艳的绿色，我们是无法打印出来的，这就是为什么打印出来的图片有可能会比显示器上的图片暗一阶的原因，记住，我们屏幕上的颜色模式是RGB，而打印颜色模式是CMYK。
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