Rgb what is this and what is it used for in computing

We are sure that in recent years you have heard the term RGB countless times, and we are also pretty sure that you have heard it when talking about motherboards, graphics cards, liquid cooling, etc. Well, today we are going to try to explain the best possible meaning of this term and why it is used so frequently in the computer world.

Index of contents

What is RGB

Well RGB is a term that is made up of the abbreviations of the terms "red", "green" and blue ", that is to say, red, green and blue, that is to say, it is related to the representation of colors. Ok, we already know what these acronyms mean, but what do they have to do with lighting and computing?

RGB is a chromatic model through which we will be able to represent different colors from the mixture of these three primary colors. Later we will explain that in addition to these colors, there are also others that are considered primary in other different color models, for example, in art or in ink printing.

This model specifically, is based on the additive synthesis of lighting in these three colors. Through this addition of colors and applying a certain luminosity to each of these three, we will be able to represent other colors different from them and thus be able to see a greater variety. A clear example of the use of the RGB system are computer monitors or televisions, from traditional CRT tubes.

The problem that arises from this representation in RGB is that these three colors are not always the same for each manufacturer, that is, there are different shades that make the combination of them generate other slightly different colors.

Why mixing three colors we can see more

What happens when we join two colors and see a different one? Well, this phenomenon is exclusively due to the functioning of our eyes and how it sends light signals to our brain.

Basically we can say that our eyes are made up of cells that are sensitive to the light we receive and thanks to them we distinguish colors. These cells are made up of some so-called rods and other so-called cones, the latter are divided into three types and are the ones that generate the color information that we see.

Each of these three types of cones operate at a different frequency and precisely have maximum sensitivity due to the three colors that RGB generates. In this way, these colors combined, new frequencies are generated that make our color sensitivity curve vary. The result is an appreciation of multiple colors with only the combination of the three basic ones to which our eyes are especially sensitive.

How an RGB Computer Screen Works

This RGB color rendering system is the one used by digital screens today. Our mobiles, television, computer monitor, all of them use the RGB system to provide us with all the colors that we see in them. But already this chromatic system began to be used in those light and thin CRT screens with an electron gun, although in quite a different way from what is currently done.

In a video signal, these three signals or colors are treated separately to provide a better representation of the colors that we see. Furthermore, to properly appreciate a dynamic image, these three signals must be perfectly synchronized in order to form the colors.

When we see an image represented on a monitor, it really is made up of a mesh of millions of light emitting diodes (LEDs). An LED is basically a diode that lights up as the voltage passes. On a screen we always give it the name of pixels, each pixel is a lighting point of our screen. If we get very close to our screen and it has a not too large pixel density (how close they are and how small they are) we will notice that there are very small squares on it.

Well, each of these pixels in turn is made up of three sub-pixels that will light up with each color. The variations in luminosity of these three pixels simultaneously will generate a certain color at that moment. When they are all off, we will have the color black and when they are all on and of equal brightness we will have the color white. The rest of the colors are tone combinations of these three sub-pixels.

Source: Wikipedia

For a monitor to be able to give a color image correctly, there are two types of signals:

Luminance signal: Luminance is basically the amount of light that an object is capable of emitting, or for us, the brightness that reaches our eyes from an object. The monitors graduate this luminance signal in each of its pixels to give us the feeling that everything shines equally, whatever the color that we are seeing. There are three types of television systems, PAL, NTSC and SECAM which transmit this luminance differently together with extra information to operate correctly. For this reason, a movie with a PAL signal may not render well on an NTSC television, since the signals work differently. Synchronization signal: in order for the image we see to be completely stable, without flickering or variations between the screen areas, we also need a synchronization signal for all the pixels. There are various synchronization systems on current monitors, RGBHV, RGBS, and RGsB.

We also use RGB in programming languages and design programs

We have already seen in a practical way how a monitor represents colors using RGB. But we still don't know how a program generates the necessary instruction for a certain color to be represented, nor do we know how many colors it is possible to represent.

Well, in HTML code for example, and in many other cases, to represent the different colors there is a code made up of three separate numbers that can take values from 0 to 255 ",, ", this forms a total of 24 bits in binary, 8 for each number. Each of these numbers represents one of the colors being,, and depending on the value of the number inside, the luminance of that color will be higher or lower, as we can guess. For example if we have,,, we would have the green color represented on the screen, if we had the,,, we would have the color white, and so on.

Those who know mathematics will know that with three coordinates we would be representing a number in 3 dimensions, and exactly the same thing happens here. The entire spectrum of colors from 0.0, 0 to 255, 255, 255 is called an RGB cube. This cube has grown over the years, depending on the range of colors that a monitor was capable of representing. The current monitors are 24 bits, therefore they are capable of representing 16.7 million colors with only the combinations of red, green and blue, incredible, right? The fewer bits, the fewer colors we will get on a screen or other RGB lighting system.

It can also be represented in hexadecimal form using a 6-character code, where " 000000 " would be black, and " FFFFFF " would be white. If we open Photoshop for example and try to choose a color for our brush, we will see that the representation code is precisely RGB in hexadecimal.

And what is RGB gaming lighting

At this point we will all have already thought about RGB lighting systems implemented by the vast majority of manufacturers of hardware and PC gaming devices. Well, these systems are basically LED diodes that contain three others that represent each of these three colors in variable luminance, in short, exactly the same as what happens with monitors, but with a larger size and more luminance.

RGB LED diode

If you look, the most basic lighting systems can represent 7 colors, which corresponds to 3 bits. Similarly, a system that can represent 256 colors will correspond to 8 bits. Thus we will go up in benefits until we find a 24-bit system capable of representing 16.7 million colors. Systems like Razer Chroma, Asus RGB Aura or MSI Mystic Light, are 24-bit lighting systems.

In one of the elements that we most often see RGB LED lighting, is in the gaming-style chassis, and in practically almost all PC fans today. Today's boxes are turning into a light show with an increasingly sophisticated system and more impressive effects. These systems carry in almost all cases perfectly manageable 24-bit lighting systems as in the case of the NZXT i range.

RGB vs CMYK

As we have already mentioned, in addition to the RGB color system there are also other types of representations, and a clear example is the CMYK color system. Instead of being made up of three colors, this system is made up of four: Cyan, Magenta, Yellow and Black. Actually, CMYK we all know, although we may not have noticed, but it is the one used by our home printers. If we remember, our printer's ink cartridges are two, one with black color and one bigger with the other three colors, there you have it, these four colors.

In this system, the color mixture is subtractive, this means that the mixture of the three primary colors on a soft background is black. The reason for calling it subtractive is because it is based on light absorption. When we use the CMYK color system in an image or in graphic design, we are ensuring that the colors that are represented in it will be faithfully reproduced in the final print. Precisely for this reason, photo editors, magazines and other media that base their product on printing always use this system instead of RGB.

In a process of converting an RGB image to a CMYK we will see that the latter is considerably paler, this is due to the real adjustment that the system makes to emulate how it would be in its printing.