The use of black cardboard is very extensive and has its place in photography

Why use black card paper?

In general, a black card can be used when a part of a photo has too much light (such as sky and ground) and is exposed for a long time. The most common is to use a black card at sunrise or sunset and at night, Because the sky and the ground exposure value is not the same, If you only measure and expose light to the level of light, the dark part will become a black silhouette, So that all the dark details are lost. Conversely, if you only measure and expose to dark areas, the light level will be overexposed. So that photos lose the degree of saturation and level, and the use of black card will be able to solve this problem.

How to use black card paper?

The usage of black card is very simple.  We only need to measure the light in the upper and lower parts before shooting, and then work out the difference. In other words, the difference between the upper exposure time and the lower exposure time.Then remove the hood and use the black card to block the proper part. From top to bottom, close to the lens before the mirror, cover to the bright position. In this way, the light level can be obscured by the black card.

As shown in the figure above, the sky part needs to be exposed for 1 second, while the ground takes 10 seconds, which covers the upper part of the lens (that is, the part of the sky) for 9 seconds. When you remove the black card, you can get 10 seconds of exposure on the ground and only one second in the sky. In this way, we can achieve the desired effect, keeping the details of the dark and light bits intact.

We can see from the above two illustrations that there are no photos of black card, and many details are too exposed. After using the black card, the details in the photos are obvious.