When moving around, surroundings sometimes go unnoticed almost as if they are without colors, the colors loose their significance because they are part of our background image.
However the colors are always there somewhere even when there is no light reflecting on the surfaces.

Color-blocking in a more traditional meaning takes colors that are the opposites on the color wheel and pair them together to make a complementary color combination, in this context color-blocking has been used to select one repesentative color from the image to enhance the overall impression of what once seemed only like a colorless background image.