Why our eyes make certain colors difficult to judge.
One of the indelible moments I took away from my design-school color theory class was the concept of simultaneous contrast. Without getting too technical about a complex subject, the idea is that color is not absolute when we see it – the appearance can change with various combinations as our eyes mix it automatically.
This is particularly true of muted colors, which contain some black, and are neither very pale nor very dark. It’s visual trickery and one reason someone with some color knowledge will never endorse painting swatches of different colors on a wall. It’s also one reason certain yellows as well as lavenders and greens are especially prone to change along with light in a room.
A favorite way to illustrate this is with a study I created [top] with color-aid paper. How many different colored papers were used in these two collages? If you see four different colors – two different backgrounds and two different centers – you are correct. However, only three different hues were actually used. The small center squares were cut from exactly the same piece of paper — yet they appear different as a result of the interplay with each background. The visual trickery occurs when an intense color such as fuchsia pushes the center square to appear lighter while against the less intense lavender background the square appears darker.
This video (kindly excuse the cheesy music) shows the same principle in action.