Dust on planet Earth is the most common substance. On black objects, the dust appears white, and on white - black. This phenomenon is due to the properties of the substance, the nature of the appearance and a number of features.
Where does the dust come from?
This substance is everywhere: in the air, on furniture, things and even people. Due to its small size, dust particles are almost invisible and visible only on the surface, if they accumulate in large quantities.
Since dust consists of decomposed particles, they do not have color pigments. As a rule, most of these molecules appear gray due to colorlessness. They owe this property to their visibility on any surface.
What does dust look like on black and white?
After setting the cause of the dust particles and their color properties, you can go on to how they look on a different background.
Each person noticed that this substance is clearly visible on black and white, and in the first case it is white, and in the second it is black. Even if you shift the same dust to the opposite surface, it will also be clearly distinguishable. Because of this, it may seem that the particles change their appearance like a chameleon, but this is not so. Dust particles always remain gray, regardless of the environment.
And their good distinguishability is due solely to the properties of light and the principle of the human eyes.When rays from the sun or artificial sources penetrate into the room, they are evenly distributed in space, falling on everything that they meet in its path.
Dust and the surface where it lies are no exception. Since the gray tone of the substance contrasts with both black and white, when light enters, it becomes even more visible.
Why is dust on a white background black and white on black?
However, why does the dust not only become more noticeable, but change color to white or black, depending on the color of the coating?
The answer to this question will give a feature of the human eye. People distinguish colors perfectly thanks to the properties of the lenses located in the eyeball. They are able to capture most of the variances in which the objects are made. However, the smaller the subject, the more difficult it is for the eye to distinguish its color.
Dust particles are microscopic, so the human body is not able to distinguish in detail the color of each. For him they represent a solid gray mass. But when the dust falls on a black or white background, the eyeball ceases to distinguish gray color, but simply sees the contrast of the elements with the surface. That is why, on dark and light objects, dust particles seem to be of the opposite color.
This principle also works in other situations. For example, if a dark brown beetle sits on a piece of paper, then at a long distance a person will see only a black dot, since the eye can not see the brown shade.
The dust is clearly distinguishable on black and white, since it itself has a gray color.It is already clearly visible to the human eye on these surfaces, and when light enters, contrast increases at all. Because of this, against a certain background, the same specks of dust appear white or black, although they do not change their structure and properties.
