Why do Computers use RGB colours instead of RYB colours?

Red, Yellow, and Blue — Primary colors. That’s what we have been told in our kindergarten, isn’t it? But there is more to it. Do you know?

If you’re a developer, you might be aware that the computers use the RGB system. Now the question is — if RYB is the primary color set then why do computers use RGB instead?

Going deep into the line, we first need to understand the color theory. There are two different theories -

  1. Additive
  2. Subtractive

Before elaborating that, let me ask you- what exactly is Light? or more specifically the visible light, like the one you see while reading this article. Without diving into electromagnetic radiations, wavelengths, and such other stuff of physics — light is just the color ( Colour ) that is reflected in our eyes.

Here is the deal — as players depend on the game, plants depend on the environment — We too have a different thesis for Primary Colors, depending on the situation. Different cases of Light & Paints ( or inks ).

Subtractive

When we mix paints or inks, subtractive mixing results. Paints or inks are non-emissive objects here. They reflect when light falls on them. Molecules of paint absorb some of the wavelengths of light and reflect rest. That’s how we see such objects.

The primary colors of the subtractive mix are — Red Green Yellow. No. They are CMYK — Cyan, Magenta, Yellow, and K which stands for black ( To distinguish it from B for Blue. Just a convention )

When the CMY ( not K ) gets mixed, it produces brownish color. Bit muddy. To get the more blackish color, the additional K for black is used. CMYK — the model used by printers & publishing houses.

Additive

The additive is the case of the projection of one or more colored lights ( wavelengths ). These are the colors when mixed produce more light. The RGB, Red-Green-Blue when mixed produces lighter colors, resulting in white light at the end. & that’s how our computer, TV, and other light-emitting screen works.

When light is emitted from a screen, it uses an additive color system. If you want to see a color ranging near to purple, the system should emit red and blue lights together.

As you know, most electronic screens are dark, the RGB model is used to emit light. Combining these colors to produce lighter colors offers a good contrast to the dark screens.

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I never realised there was so much complexity behind something as seemingly simple as colours! Have you ever noticed how these color systems impact your everyday life, especially when it comes to technology or printing?

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