RGB Color Model: Adding Color To The Digitized World

We did not always have bright colors and hues of light representing our digital system as we do today. Actually, the first experiment with color photography was only done in 1861, less than 200 years ago. J.C. Maxwell took the first permanent color photograph, using three filters, specifically red, green, and violet-blue. So, this color model is now known as the RGB color model.

We use RGB color model to combine and display the colors that we see on our digital screens like smartphones, television screens, and computer monitors.

What is the RGB color model?

The RGB color model

The RGB color model is an additive color model that uses the three primary colors- red, green, and blue. Thus, a variety of color ranges can be made from this model varying the intensity of the individual colors. If the three colors are superimposed with the least intensity, it forms black color. And, if superimposed with the high intensity of all three colors, it forms white color. The intensity of each primary color can vary from 0 to 255.

The number of colors that we can create depends on the value of the RGB. We measure the color depth in ‘bits’. It uses 24 bits, 8 bits for each color. In that way, it provides 2^8 or 256 possible values for red, green, and blue. As a result, we can create a total of 16,777,216 different shades using the RGB.

How does it work?

As already stated above, the basic principle behind the working of the RGB color is additive mixing. The color model uses the three primary colors red, blue, and green and mixes them in different proportions to produce an array of different colors. For humans, cone cells or photoreceptors are the ones responsible for color perception. We perceive the different colors created by the RGB model by stimulating our cone cells simultaneously.

When the three light beams are added together, their light spectra add all the wavelengths to make the final color’s spectrum. In a digital image, each pixel has its own specific RGB value. The value of this can be anywhere between 0 and 255. 0 means no color whereas 255 means full saturation. For example, the color purple has the following RGB value:

R: 132   (84 in hexadecimal)
G: 17   (11 in hexadecimal)
B: 170   (AA in hexadecimal)

We can also represent colors using two hexadecimal values (16*16). To display the RGB value for purple, we combine the hexadecimal values for red, green, and blue. A hashtag, number, or symbol usually precedes these values. Thus, the color purple has the RGB definition of #8411AA.

Uses of the RGB color model

RGB Definition: What is RGB, How Does RGB Work, and More — Using RGB Color
  • Camera: The three primary red, green, and blue light together make daylight. Maxwell first created a color photograph by placing red, green, and blue filters over individual pixels on the image sensor. The CMOS or CCD image sensor used nowadays performs with an RGB model. Accordingly, the camera computes the actual color of each pixel by using interpolation and combines the color it captures directly through its own filter with the other two colors captured by the pixels around it. The image quality however depends on its format, size, and compression.
  • Display Screens: The main use of RGB color model is for digital display. LED displays like large screens, computer monitors, televisions, LCD displays and cathode ray tubes use this color model to display color images. Three very small and close RGB light sources are in each pixel of these displays. Looking at the screens at a normal viewing distance, we cannot distinguish the individual colors. But, in a closer inspection, we can identify the individual pixels. On-screen applications like graphic design and digital editors like Microsoft Office, Adobe Creative Suite (InDesign, Photoshop, etc.) all are compatible with RGB.
  • Scanner: There are different types of image scanners. Most of these work based on the RGB color model. They use a charge-coupled device or contact image sensor as the image sensor. Likewise, these types of color scanners often read data as RGB values. Then, these data are processed with some algorithm to convert to other colors.

RGB Vs CMYK color model

RGB Definition: What is RGB, How Does RGB Work, and More — RGB vs CMYK

We use both RGB and CMYK color models for mixing colors. However, they both have areas that they are more well-suited for. For example, RGB model is better for digital representation whereas CMYK is better for physical printing. CMYK stands for Cyan, Magenta, Yellow, and Key/Black. CMYK color model uses the subtractive mixing, while on the contrary RGB color model uses the additive mixing. The intensity of each light is added in RGB model to produce the desired color. The highest intensity of all three light beams superimposes to create the color white. In contrast, each added layer of ink in a CMYK color model reduces the brightness to achieve the desired color. The four colors in a CMYK model mix together to create pure black.

The CMYK color model also has a much smaller range of colors than a screen is capable of. It can make many different shades and hues, but it will never have the same depth as the RGB color profile.

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