How to choose blue phase carbon black and red phase carbon black?

　　Carbon black generally has a hue, but the reason why only pigment carbon black is mentioned here is that the hue is only considered when choosing pigment carbon black, and other carbon blacks generally do not pay attention to hue. Only when you check the pigment carbon black index, you will find the blue phase carbon black and red phase carbon black. Many people will wonder, isn’t carbon black all black? How can there be red and blue phases? In such a situation, how to choose blue phase carbon black and red phase carbon black?

　　What is the relationship between hue and carbon black?

　　The blackness of pigment carbon black has the most direct relationship with its original particle size. The smaller the original particle size, the higher its own blackness and the more obvious the red phase. The higher the requirements for the grinding equipment; the carbon black products with larger particle size will show a better blue phase, but their own blackness is not as good as the former. Black is created by all sunlight being absorbed, with no visual representation of reflected light. At the same time, we know that very small particles reflect very little light. In physics, there is a certain relationship between wavelength and particle size. For black pigments, it means that the particle distribution of carbon black particles in the final coating determines which wavelengths of light will be reflected better and faster.

　　The principle of carbon black phase

　　The size of carbon black particles is different, and the scattered and transmitted color light is also different. The finer the carbon black, the more scattered the blue light is, and the thicker it is, the more red and yellow are scattered. Transmitted light is just the opposite. In fact, all transparent colors conform to this principle, but carbon black is achromatic and easier to observe.

　　How to choose blue phase carbon black and red phase carbon black?

　　Regarding the choice of carbon black phase, there is no need for special selection, of course the final color can be adjusted by other means. The most important thing is to see whether other indicators of carbon black can meet its use requirements. Of course, the carbon black product has a small particle size and high blackness, and it will show a red phase, otherwise it will show a blue phase. However, pure blue color has high blackness, suitable for solid color or deep black color, but it is reddish yellow when diluted. To eliminate this part of red color, you need to add some blue or blue purple to offset it, which will more easily lead to floating color and blooming. ;As for the black that dilutes the blue phase, the blackness of the pure color is not enough, it belongs to low-pigment carbon black, especially in metallic flash paint, the red-yellow phase after dilution of high-pigment carbon black is difficult to eliminate, use blue-violet offset, positive side Light is difficult to control well.