What is a potential downside of using gain in video signals?

Using gain in video signals can indeed amplify imperfections, which can manifest as noise in the final video output. When gain is applied, the signal strength is increased, but this also means that any existing noise in the signal gets amplified as well. Noise can come from various sources, including inherent sensor noise, electrical interference, and compression artifacts. As the gain increases, these unwanted signals can become more prominent, degrading the overall quality of the video. This can be particularly problematic in low-light conditions, where noise is often more noticeable. Therefore, while gain can improve the brightness of an image, it may also inadvertently highlight imperfections that detract from the clarity and fidelity of the video.