What are the three additive primary colors of light

The inner surfaces of your eyes contain photoreceptors—specialized cells that are sensitive to light and relay messages to your brain. There are two types of photoreceptors: cones (which are sensitive to color) and rods (which are more sensitive to intensity). You are able to “see” an object when light from the object enters your eyes and strikes these photoreceptors.
Índice Show

Additive (Light) Color Primaries
Subtractive (Pigment) Color Primaries
Watch This Demo For a Better Understanding
Production of Additive Color
Cartographic Application

Some objects are luminous and give off their own light; all other objects can only be seen if they reflect light into your eyes. However, humans can only see visible light, a narrow band of the electromagnetic spectrum (which also includes non-visible radio waves, infrared light, ultraviolet light, X-rays, and gamma rays). In terms of wavelengths, visible light ranges from about 400 nm to 700 nm.

Different wavelengths of light are perceived as different colors. For example, light with a wavelength of about 400 nm is seen as violet, and light with a wavelength of about 700 nm is seen as red. However, it is not typical to see light of a single wavelength. You are able to perceive all colors because there are three sets of cones in your eyes—one set that is most sensitive to red light, another that is most sensitive to green light, and a third that is most sensitive to blue light.

Source: Harvard—Smithsonian Center for Astrophysics
This media asset was adapted from Shedding Light on Science

This is where color can get a little confusing for some folks. There are two basic color models that art and design students need to learn in order to have an expert command over color, whether doing print publications in graphic design or combining pigment for printing. These two color models are:

Light Color Primaries (Red, Green, Blue)
Pigment Color Primaries (Cyan, Magenta, Yellow)

Some of you might be scratching your heads, asking, “Where is the Blue, Red, and Yellow model?” The artist color wheel (based in blue, red, and yellow) predates modern science and was discovered by Newton’s prism experiments. Scientifically, this does not adequately address the true range of spectral color. Upon discovering more about spectral color and how wavelengths work with surfaces (reflection/absorption) and the human eye, the blue-red-yellow model is shifting to the cyan-magenta-yellow model. We DO, however, still use the RBY model for mixing paints, and it is the most common color wheel students will typically find in art stores.

Primary Color Models

Additive (Light) Color Primaries

Red, green, and blue are the primary colors of light—they can be combined in different proportions to make all other colors. For example, red light and green light added together are seen as yellow light. This additive color system is used by light sources, such as televisions and computer monitors, to create a wide range of colors. When different proportions of red, green, and blue light enter your eye, your brain is able to interpret the different combinations as different colors.

Source: Harvard—Smithsonian Center for Astrophysics
This media asset was adapted from Shedding Light on Science

Additive (Light) Cheat Sheet

Color is transmitted through transparent media.
All colors added together = white.
The absence of light = true black.
Because computer graphics, websites, and other digital presentations are projected/transmitted with light, screen-targeted graphics should be saved in this color model, or “RGB Mode.”
IMPORTANT: Note that when RGB’s primaries are mixed evenly that they create the secondary colors of our next color model, CMY (cyan, magenta, and yellow)!

Subtractive (Pigment) Color Primaries

However, there is another set of primary colors with which you may be more familiar. The primary colors of pigment (also known as subtractive primaries) are used when producing colors from reflected light; for example, when mixing paint or using a color printer. The primary colors of pigment are magenta, yellow, and cyan (commonly simplified as red, yellow, and blue).

Pigments are chemicals that absorb selective wavelengths—they prevent certain wavelengths of light from being transmitted or reflected. Because paints contain pigments, when white light (which is composed of red, green, and blue light) shines on colored paint, only some of the wavelengths of light are reflected. For example, cyan paint absorbs red light but reflects blue and green light; yellow paint absorbs blue light but reflects red and green light. If cyan paint is mixed with yellow paint, you see green paint because both red and blue light are absorbed and only green light is reflected.

Source: Harvard—Smithsonian Center for Astrophysics
This media asset was adapted from Shedding Light on Science

Subtractive (Pigment) Cheat Sheet

These primaries are ultimately derived from the RGB model as secondary colors. The main reason they are promoted to having their own color model is because it is from CMY that we can create all other printable colors. Remember that, ultimately, without the existence of RGB light wavelengths, we would see nothing.
Color is absorbed by and reflected off of media.
Because these colors are achieved via reflection, we assume a pure white ground as the base filter for pure colors.
All colors added together = near black.
To achieve true black, pure black must be added, thus giving us the CMYK model (K=black). This is the standard color model for most printing, thus graphics for print are typically prepared in “CMYK Mode.”
While most printers recognize this model as the standard pigment model, the traditional artist Color Wheel substitutes Blue as the Cyan primary and Red as the Magenta primary, resulting in slightly different secondary and tertiary results.

NOTICE: The colors in RGB appear slightly more brilliant than in CMYK. This can be attributed to the difference between the mode of transmitting light vs. absorbing/reflecting light off of surfaces.

Watch This Demo For a Better Understanding

>>>>>> Demo on Light and Pigment Primaries <<<<<<

Extra:

***Download the PDF diagram and explanation of the Additive and Subtractive Color Models here.

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From wiki.gis.com

Red, green, and blue are the primary colors in the additive color system.

Additive primary colors are colors which produce the color white when added together. The additive primary colors are red, green and blue. Colors in the additive color system are produced from the combination of different intensities of red, green, and blue light. A complete absence of all additive primary colors appears black, while equal intensities form white. This system is essentially the opposite of the subtractive color system, which produces black when equal intensities of its primary colors are mixed.[1][2][3]

Production of Additive Color

Visible Light is the portion of the electromagnetic spectrum that can be perceived by the human eye. The visible light spectrum consists of wavelengths that produce colors from violet (~400 nm) to red (~700 nm)[4]. However, red, green, and blue wavelengths are considered the primary additive colors because combinations of these colors can produce almost any other color. When equal parts of each of the three primary colors are combined, the result is white light[5]. The complete absence of the three primary colors results in no color, or black. According to the Media College, " Additive primaries describe the colours we see in the real world, created by light" [6].

When only two primary colors are combined, each at full intensity, it creates an additive secondary color. The secondary colors are cyan, magenta, and yellow. By changing the intensity of the primary colors, most of the other colors can be produced. These are some of the possible combinations that create new colors[7].

Red + Blue = Magenta, Red + Green = Yellow, Blue + Green = Cyan, Red + Blue + Green = White.

Additive colors are created by anything that emits its own light source, whereas subtractive primary colors are used when light is being absorbed and reflected. One of the more important applications of additive color is in projection technology, such as television or in computer monitors. These technologies use the RGB color model in order to produce many of the different colors on the spectrum. Each pixel has three sub pixels that emit red, green, or blue light. By changing the intensity of each sub pixel, each pixel emits a color that forms the display.

Cartographic Application

Additive primary colors are used when working with maps on a computer screen, but when the map is printed on a medium, subtractive primary colors are formed from the ink. It is important to take this into account when planning map design because subtle color changes could occur as the additive primary colors on the screen are converted to subtractive primary colors on printed paper. This could alter the effectiveness of the color scheme of the map. [8] James Clerk Maxwell is said to be the father of additive colors.

References

↑ Color theory, ColoRotate. Accessed 10 September 2016.
↑ Color Systems, worqx.com. Accessed 10 September 2016
↑ Primary Colors, Hyperphysics, Georgia State University Web site. Accessed 12 September 2011.
↑ What Wavelength Goes with a Color?, NASA Langley Research Center’s Science Directorate Education and Public Outreach Website.Accessed 17 September 2017.
↑ Primary Colors, Hyperphysics, Georgia State University Web site. Accessed 12 September 2011.
↑ http://www.mediacollege.com/lighting/colour/additive-primaries.html
↑ http://www.mediacollege.com/lighting/colour/additive-primaries.html
↑ Additive color, Wikipedia contributors, Wikipedia, The Free Encyclopedia. Accessed 12 September 2011.