This is a guide covering RGB color.
We’ll be covering the topics of:
- Definition of RGB
- Why is it Called RGB?
- What is the Purpose of RGB Color?
- How Does RGB Color Work?
- Who Invented RGB Color and When?
- What is the Difference Between CMYK and RGB?
- And more
Red, green, and blue lights are a part of the RGB color system and you see the images from the computer screen when the light emitted by the screen stimulates our eyes.
To better understand what RGB is and what it offers us, we need to first understand the RGB definition, why we call it RGB, its purpose on the web, and how to use it.
You also need to understand the difference between RGB, and CMKY so you can take advantage of it instead of printing dull images.
Let’s dive in.
What is RGB (Definition)?
RGB stands for the primary colors, red, green, and blue. These RGB colors are the basic colors used for displaying images, objects, etc. on electronic screens. RGB is used for electronic displays such as TV screens, smartphones, etc. It’s typically used for digital display while CMYK is used for printing color images, papers, brochures, etc.
You might be thinking that we don’t see everything in just red, green, and blue lights but different colors as well.
This is because more colors can be found by combining two colors, e.g., red and blue make magenta, blue and green make cyan (a lighter shade of blue) and red and green make yellow.
Using all three lights at once will produce white and black is produced when there is no light of any color on the screen.
The RGB color lights are additive, which means that the more you combine two colors, the more vivid the resulting color’s shade will become.
This attribute makes them perfect for displaying in softcopy on electronic screens.
Why is it Called RGB?
RGB definition refers to what it stands for; ‘R’ is for red, ‘G’ is for green and ‘B’ is for Blue.
These are the three colors that are typically needed for our eyes to see colors on the computer screen.
Red, green, and blue lights are combined in different combinations to make other colors that we see on the screens.
When we combine all three lights, we get white, and when we combine or use no light, we get black.
Computer screens consist of small units called pixels.
One pixel has a subunit for each of the three colors and this is the reason why RGB is the color system used for digital communication.
It also offers more vibrant colors since it has a wider array of colors.
What is the Purpose of RGB Color?
RGB is preferred for digital display because it offers a wide variety of colors to choose from.
It’s used because our computer screens – the digital monitors – are made up of tiny pixels, and these pixels allow us to see images of the screen.
These small pixels consist of three light units, and each unit corresponds to red, green, and blue – the lights that make up the RGB color system.
This system is also flexible and allows users to use additional data.
It’s also prevalent in the web world, especially in web design, and it is easy to use, but every device has a different color against one RGB value so every device often has a slightly different shade of the same color.
RGB values are written in hexadecimal with a #, followed by hexadecimal (0-9 and a-f) values of red, green, and blue, in that exact order.
Every color in this scheme has a value assigned to it, and we use hexadecimal to represent them because writing them in bits can be a handful e.g., hex code for white is #ffffff and for black, #000000.
RGB is compatible with all the applications found on our computers such as Adobe Creative Suite and Microsoft Office.
It’s also used in a display such as LCD and LED screen – TV and computer PC, laptop and mobile phones.
Moreover, it’s used in cameras and scanners, especially image scanners, that change a hard copy image to a digital image via a scanner.
How Does RGB Color Work?
As the RGB meaning says, for digital display, we need red, green, and blue but this begs the question.
Why not RBY – red, blue, and yellow?
Red, blue and yellow are the basic primary colors that can make up the typical color system but red, green and blue are the main three lights.
Since RGB corresponds to digital communication, we talk about lights here instead of colors.
The other reason why red, green, and blue are used is that digital display works with pixels.
Each pixel has subpixels known as red, green, and blue, which handle the color part of the screen.
Any digital display emits light that makes it possible for us to see the images on the screen.
Light has a wavelength, and some wavelengths stimulate our eyes more.
The many different wavelengths lead to a different response from the brain, and the brain perceives these wavelengths as colors.
The wavelengths emitted by the screen stimulate the receptors in the brain, and these receptors – the cones – are divided into cells that can see red, green, and blue, and that’s why digital display uses an RGB scheme.
In total, we can see 16 million-plus colors from a computer screen.
Why 16 million+ colors? The reason is because of the color depth.
The color depth is the number of colors that determines the number of colors you can see on the screen, and we use bits to measure it.
A 2-bit color depth means only two colors, black and white and a 16-bit color depth allows for a greyscale image, but these aren’t used for digital display anymore.
Instead, the 24-bit color depth is commonly preferred since it allows for up to 256 values for each of the three colors, red, green, and blue.
The total number of colors the human eye can see from a digital screen equals 16,777,216 (256 x 256 x 256).
Who Invented RGB Color and When?
It may seem like a new invention since it relates to a part of the computer software, but we can trace it back to the 1800s.
Thomas Young, James Maxwell and Hermann Helmholtz are considered the pioneers of RGB.
However, before they could discover the wonders of these three colors in the vast color spectrum, between 1670 and 1675, Isaac Newton established the link between colors and our eyes (the cones and lights).
In 1802, Thomas Young concluded that there are three colors – red, green, and blue – that our eye’s color receptors are sensitive to.
In 1850, Hermann Helmholtz conducted an experiment where he asked the subjects to look at and compare monochrome light sources from a different sample.
The results led him to believe there were three primary colors from which we can derive other colors, red, green, and blue.
In the 1860s, John Maxwell worked on the three primary colors out that Thomas Young had discovered things that are considered the foundation for modern colorimetry.
Moreover, between the 1920s and 1930s, after physicists came to understand the inner working of the human eyes, experiments allowed them to conclude that red, green and blue are the primary colors of light, and light is the reason we see colors.
Before all color television became common, black and white televisions were typical since the pixels on the screen could handle a 2-bit color depth.
In 1928, however, everything changed. John Logie Baird showed the first-ever RGB TV transmission with more colors than just black and white. He is known as the color TV pioneer.
The RGB lights system can’t be attributed to just one person in history because it was discovered and developed through theories founded by many genius physicists.
What is the Difference Between CMYK and RGB?
RGB is typically used for digital display, such as CRT, digital cameras, and LCD, while CMYK is used for printing color images, papers, brochures, etc.
Alternatively, CMYK refers to the colors associated with hard copy printing.
CMYK stands for cyan, yellow, magenta, and black.
Both RGB and CMYK are different and have several differences, but they are both color systems we use.
RGB system relies on the addition of colors or lights, and it’s known as an additive model, while CMYK operates through the subtraction of colors.
Additive property means that when all the three colors are mixed, they make white light, but when no color is mixed, black is produced.
On the other hand, in subtractive combination (CMYK), when we add all the colors, the result is a very dark brown color.
Note that this subtractive combination doesn’t produce black, hence the reason why we have black ink too; this black ink takes all the light put from the page so we see black.
But, when we add no color together, we get white – the printing page is white so we see white where no color was printed.
However, RGB is not best suited for printing but only for the web. For printing, we have the CMYK color system.
If we were to print an image from the web/softcopy form, the resulting image will come out dull and less colorful because CMYK has fewer colors.
CMYK has fewer colors, and the additive model has more colors so when we print it, we have to first convert RGB to CMYK format because these are the printing colors.
To convert the image format to CMYK, you can use design software like Adobe Illustrator or Adobe Photoshop.
The RGB system has these three primary colors of lights that allow our eyes to perceive colors on the screen.
These lights have different wavelengths and by mixing different wavelengths, we get different colors.
When different wavelengths of light are combined with different intensities, the resulting wavelength stimulates various parts of the photoreceptors – the cones – in the brain, and that’s why we’re able to see bright colors.
You can effectively use RGB for the web if you understand its purpose and know how to use it.
Moreover, you need to able to change an RGB format to CMYK if you want to print images that reflect their softcopy equivalent.
Jon has been a passionate photographer for 10+ years. Fun fact is that he has a collection of around 300-400 cameras that his family has collected over the years. Outside of photography, he has a Masters Degree in Engineering and has 13 years experience working in the industry across the globe.