So far humans have identified about sixty types of color. Only those with very sharp eyesight can distinguish among them. What the human eye perceives is expressed in terms of color, light, gemstones, and finally to some extent water.
Regardless of what the color of the sky truly is, how it is formed, or whether it is only imaginary or a reality, the human eye perceives it, and the name it gives to it is sky blue.
When the atmosphere is completely free of dust and particles, the rays of the sky’s color change according to their position. By position is meant the space that humans refer to as height, depth, vastness, or proximity or distance from the earth. These conditions make the sky’s color lighter, darker, deeper, or paler, to the extent that it appears in various hues.
If we look from the horizon toward the earth, we find countless rays of blue color. Here, the word color can be described as a type. In fact, it is this type that our eyes recognize as color. The variations in color are not merely color alone; they also contain many other elements present in the atmosphere that alter them. It is this combination we refer to as a type.
The appearance of color that we see contains light, oxygen gas, nitrogen gas, and traces of other gases as well. Along with these gases, there are also shades, some light and some dense, and other components that blend into the color of the sky. These components are what we call different types or different colors, but we must not forget that light and dense shades hold great importance among them.
In the atmosphere through which we perceive differences in color, much exists between the eye and the limit of vision even when the sky appears perfectly clear.
By Khawaja Shamuddin Azeemi RA, from his book: Healing with Colors and Light