When Should I Use the Black Level Camera Feature#

There are three main scenarios for adjusting the black level:

You may have a setup in which you can't see all the values in dark. You'll see a lot of pixel values being zero in the image. With a higher black level value, you can move the image to higher values and reduce the zeros.
You may have a very small distribution of gray values (e.g., 64 to 127 on an 8-bit scale). Using a gain of x2 will set the range from 128 to 254, but you still use only half of the bit range. With an additional negative offset (-64) you could drag the range down to, e.g., 64 to 190 and use some more gain. Doing so stretches your histogram.
You may have to adjust the black level of the camera taps. This is especially needed when having tap balancing topics. It is recommended to align the channels with black level in dark and then again with gain in the bright field.