Even when we just look around, a wide variety of colors is readily visible. We are surrounded by an infinite variety of colors in our daily lives. However, unlike length or weight, there is no physical scale for measuring color, making
it unlikely that everyone will express it in the same way when asked what a certain color is. For example, if we say "blue ocean" or "blue sky", each individual will imagine different blue colors, because their color sensitivity and past experiences are different. This is the difficulty with color.
We also do not understand the mechanism of commonplace phenomena concerning colors such as "Why do apples look red?".
This section describes important and useful information about colors.
Human beings can perceive specific wavelengths as colors.
To better understand accurate color expression, let’s take a look at the world of color.
There are many different “red” colors. The reds of the two balls at left are very similar. How are they different?
Two red balls are shown at left. At first glance they look the same, but upon closer examination you realize they are different in several ways. The color of both is red, but the color of the upper ball is somewhat brighter and the color of the lower ball is thus darker. Also, the color of the upper ball appears vivid. So you can see that even though they both appear red, the colors of the two balls are different. When colors are classified, they can be expressed in terms of their hue (color), lightness (brightness), and saturation (vividness).