Primary and secondary colors

The main difference between primary and secondary colors is that secondary colors arise out of the mix of the primary colors, while the primary cannot be obtained from any mixture.

	Primary colors	Secondary colours
Definition	Colors that are not obtained from mixing between colors.	Colors that are obtained by mixing equal parts of two primary colors.
Examples	Red, yellow and blue.	Orange, green and purple.
Classification	RGB model. CMY model. Model RYB. Psychological primary colors.	Subtractive color model. Additive color model. RYB color model.

What are primary colors?

Primary colors are those that they cannot be obtained from any mix between colors, for this they are considered unique and absolute. Consequently, it is possible to mix a wider range of tones with them..

An important factor that identifies primary colors is that each one is completely different and unique. They do not reflect nuances in common between them.

The traditional primary colors are red, yellow and blue. However, over time, new scientific discoveries have emerged to determine what the primary colors are..

Currently there are various models to identify primary colors, the most common are models where three main primary colors prevail. They are three colors due to human trichromatic vision where there are three types of receptors that respond to very specific wavelengths of light.

Examples of primary colors: cyan, magenta and yellow.

Primary color classification

There are different theories of color that have been given the task of identifying primary colors, modern theory distinguishes between colors, light and pigment:

• Light primary colors (RGB model): Red, green and blue.
• Primary colors pigment (CMY model): Cyan, magenta, and yellow.
• Traditional primary colors (RYB model): Red, yellow and blue.
• Psychological primary colors: red, yellow, green and blue.

What are secondary colors?

Secondary colors are those that arise out of the mix in equal proportions of two primary colors. By mixing a primary color with its secondary color, what is called a tertiary color is produced..

As with primary colors, secondary colors are identified as such by the human eye depending on the source, nature and material that represents and generates the color, in addition to the subjective characteristics of visual perception..

From the mixtures between the primary colors secondary colors arise such as green, violet and orange. However, different models have been studied to determine which are the secondary colors.

Examples of secondary colors: red, green, blue and black.

Secondary color classification

According to the subtractive color model

Secondary colors according to the subtractive model originate from the mixture of cyan, magenta and yellow.

• Magenta + yellow = red.
• Yellow + cyan = green.
• Cyan + magenta = blue.
• Cyan + magenta + yellow = black.

According to the additive color model

According to the additive color model, secondary colors originate from a mixture of red, green, and blue..

• Red + green = yellow.
• Red + blue = magenta.
• Green + blue = cyan.

According to RYB color model

For the RYB color model, secondary colors originate from a mixture of blue, yellow, and red.

• Red + yellow = orange.
• Yellow + blue = green.
• Blue + red = purple.

Origin of the color wheel

Isaac Newton was the first to study primary colors and their derivatives in his book Opticks (1704), stating that there are seven basic colors in light. In addition, he made important contributions to optics, such as the creation of the first chromatic circle.

The chromatic circle that we know today arises from the primary colors. In this circle you can see the primary colors in equidistant positions, where the mixture of two primary colors give rise to secondary colors, and from the mix of a primary color with its secondary a tertiary color emerges.

Newton discovered that these colors that we perceive can be identified thanks to light, since it reflects the pigment of the substances that compose them.

The human eye through receptor cells can identify colors and interpret them through a biological response process that is possible thanks to light and its interferences. Depending on the longitudinal distances, the eye will interpret different colors.