What's the reason behind a portrait in the mirror, a needle, and a black cloth bag?

The purpose of placing black cloth is because it "absorbs light".

We usually see the color of a certain object because it reflects the color in the light.

So the color of the object we talk about is actually the color it reflects. The color of that color.

A black object absorbs all the colors of the light source shining on it, and it becomes black;

In order to control the sides of the subject in the studio, The light shining on it should also be hung with black cloth on both sides,

to prevent stray light or excess reflected light from the subject from entering the lens and being recorded in the image. The best light-absorbing cloth is black velvet, which has the strongest light-absorbing ability, but of course the price is slightly higher.

There are many things that can block the light of the mirror. For example, a black cloth can block the light of the mirror.

Because the light of the sun or the light of artificial lights is difficult to Wearing it made of black cloth,

so this kind of black cloth has a very good effect of blocking light, and can also be used as the light in front of the mirror. Under this kind of blocking You can filter out some unnecessary light