This fact makes color the most relative medium in art.
–Josef Albers, Interaction of Color
Our perception of color is constantly influenced by the relationship between a given color and it's surrounding color (or colors) and is an important principle to be mindful of when working with color. Below is a simple example of this principle similar to the studies found in the above quoted book (Interaction of Color - Albers, Josef). The two small squares in the illustration below are the same color but have been purposefully made to appear different by placing them on particular background colors.
This principle can also be seen within our products as well. As an example, the 'IBM blue' of our application icons can appear to be different in varying contexts i.e. the dark backgrounds of our mobile applications and the lighter backgrounds we use in our web UIs. The following two Connections icons are identical but have been placed on a light and dark background. It's not as stark as the above example, but you can see how the left icon appears to be more vibrant than the icon on the right, even though they are both identical.