We often use plenty of free space around our designs, but this might not always be a good idea. Consider the following case, where the user scrolls to reveal more of the area B, while hiding area A (parallax scrolling).
In the following table I have marked with 0 the screen areas that have either no content or just a predominant solid color and with 1 screen areas that have an interesting content. There are a couple of combinations that can happen as the user scrolls.
The second problem with the quick alternations between different colored areas that constantly appear and disappear is that this may cause eye strain. It seems a good idea to try to minimize the dynamics of (global) perception as much as possible. If we transition smoothly between the different background colors, this could reduce the harshness on the border between the different light intensities. But how exactly this is done can make all the difference.