Lesson 3 : Perceptually uniform color space


You are now aware that color is distributed very differently in different color spaces. The same amount of movement in one color space will create very different changes in other color spaces. In the RGB color space, where red can be defined from 0 to 255, a small numerical change change can lead to a much bigger visually noticeable change and a large numerical change can create very little noticeable change. In other words most color spaces are not uniform – except for the Lab Color Space.

Lab is a perceptually uniform Color Space

In the Lab color space, any movement in any direction creates the same amount of noticeable difference. It maps the way the human eye detects color. You can see that in the 6 colored balls around the central ball. Wherever you are in the lab space, you will notice that the color difference in all directions per unit of distance would be the same, because it is a perceptually uniform color space. That is, if you move by a single unit from any point in the color space in any direction the noticeable color difference between that point and the central point will be the same.


Activity

Move the central ball in Lab Space and notice the colors around the other four balls. The balls are spaced equally around the central ball.  Note that while is moves in the color space, the colors will change but the color difference will remain the same. This only occurs in the Lab color space.You may also notice that the position of the same colors equally spaced are considerably deformed in RGB and HSV color spaces – implying that they are non-uniform color spaces.

Learn

In a perceptually uniform Lab color space, a unit movement in any direction will create the same amount of noticeable difference to the human eye. Thus, the Lab color space is the most ideal color space not only to understand color but also to create color schemes on.



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