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 blue phase carbon black and red phase carbon black. In such a situation, how to choose blue phase carbon black and red phase carbon black?
What is the relationship between hue and pigment carbon black?
The blackness of pigment carbon black has the most direct relationship with its own original particle size. The smaller the original particle size, the higher its own blackness, the more obvious the red phase will be, and the higher the requirements for grinding equipment in actual use; carbon black products with larger particle sizes will show a better blue phase relatively speaking, 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 hue
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 hue carbon black and red hue 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 shades have high blackness and are suitable for pure or deep black colors. When diluted, they appear reddish-yellow. To eliminate this part of the redness, you need to add some blue or blue-purple offset, which will more easily lead to floating and blooming colors; and dilute blue shades.