▷ What is the color space of a monitor. srgb, dci

Have you ever heard of the color space of a monitor ? It is not a novelty that every day electronic products implement new features and become increasingly powerful and sophisticated, and exactly the same thing happens in monitors. They always pursue the same goal, that the image they give is as true as possible to reality, this is where the concept of color space comes in and the terms sRGB, Adobe RGB, DCI-P3, Rec.709, etc.

Index of contents

We will explain what color space is and why it is so important to monitors, especially professionally designed monitors. In addition, we will see the concepts related to them and how to identify them.

The color depth of a monitor

Before talking about color space, it is worth learning about another very important concept of monitors, and that is color depth.

Color depth refers to the number of bits required by a monitor to represent the color of a pixel on its screen. We will already know that the pixels of a screen are the cells in charge of representing the colors on it, and they are always made up of three sub-pixels that represent the three primary colors (Red Green and Blue or RGB), whose combination and tones will generate all the existing colors..

Color depth is measured in bits per pixel (bpp) and the binary system with which computers always work is used. When a monitor has a bit depth of "n", it means that this pixel is capable of representing 2 ⁿ different colors on it. To represent these colors, what is done is to vary the luminous intensity of the pixel in as many jumps as colors it is capable of representing.

How color bits work

But of course, we have said that each of these pixels has three subpixels, so to speak, through which we will be able to represent all colors. So we are not only going to vary the light intensity of a sub-pixel, but of the three at the same time, each one of them with its “n” bits. Depending on the combination of intensities, the colors will be formed, the same as when we mix them in a painter's palette.

Let's see examples:

Today's monitors typically have 8 bits or 10 bits, so how many colors are they capable of representing on each of their pixels?

Well, if we have an 8-bit panel, it means that a sub-pixel generates 2 ⁸ = 256 colors or intensities. We have three of them, so in combination 256x256x256, this panel will be able to represent 16, 777, 216 different colors.

Doing the same with a 10-bit panel, we can represent 1024x1024x1024 colors, that is, 1, 073, 741, 824 colors.

We already know how and how many colors the monitors can represent, now we can better define what color space is.

Color space of a monitor

If before we saw how many colors could be represented on a monitor, now we must talk about what colors are going to be represented on this monitor, since it is not the same. In real life, far more colors than a monitor can represent, as many as there are wavelengths in the visible spectrum.

Mathematically, there are infinite values ​​of wavelength, since they are values ​​that belong to real numbers, what happens is that our eyes, and that of all living beings, are capable of transforming a limited number of waves into colors. and studies carried out indicate that we are able to distinguish up to 10 million colors, depending on each human, millions above, millions below.

So a color space is an interpretation system for the colors that will be displayed, or what is the same, the set of colors and their organization in an image or video. We are talking about artificial gadgets, and that is why each one of them may have a certain way of interpreting and creating colors, and this is what is called color space, color model or also color profile.

In summary, the color model is nothing more than a mathematical model that describes the way in which colors are going to be represented, through combinations of numbers, since a computer only understands numbers, not photons. Color models are, for example, RGB or CMYK that printers use, with them we will represent on our monitor in the most faithful way what we will later see in reality.

ICC Profile

When we talk about ICC profile we are referring to the set of data that characterize a color space. It is called ICC because these profiles or color space are contained in.ICC or.ICM format files.

Cata screen or devices that comes color, must have an.ICC file

So what is a color space for and what types are there?

Each defined color space will have its own color tones and will be able to represent a certain number of them. For example, RGB space is not the same as CMYK, because the colors captured by a camera are not the same as those that a printer is capable of printing.

Each color space is in charge of faithfully representing what in reality we would see if we transferred those colors to reality. In addition to these two, there are also other spaces that are generated by a certain model and a reference panel to obtain another color range. This is how other spaces such as Adobe RGB or sRGB are generated.

In general, monitors generate colors through RGB space and depending on the medium, phosphor CRT or LCD screens will take different colors. In mathematical terms these colors are formed from the three axes of space, that is, they represent a 3D model on the X, Y and Z axes.

Each color space is oriented to a different scope or program. Their existence is oriented to design work, and they are the ones that will really give effective use to them. For example, there are spaces oriented to graphic design of digital images, to the design of magazines and paper documents, or also to video editing.

At this point we have to be color fidelity, the more similar the color that represents a monitor to reality, the greater color fidelity there will be. There are different standards that have defined their own color space, which is nothing more than the range of colors with which we could work in a program. So if our monitor can represent exactly those colors that the standard has defined, we will have a 100% color space.

RGB (Basic)

It is based on the mixing of additive colors red, green and blue, and with them we will be able to represent all the colors by means of addition mixing. Depending on the type of base color used, the color scheme will vary slightly, although this usually happens in reality. There are several RGB variants used for photography and design:

• sRGB: It is defined by HP and Microsoft and the range of colors is quite limited, not being available many of the colors with higher saturation than there are. This color space is used in the Web, cameras, and bitmap files. sRGB comprises about 69.4% of the colors that the human eye can see. Almost all mid-high range monitors are capable of representing this space. Adobe RGB: it provides a larger range of colors to represent and is intended for graphic design professionals and is widely used in the photographic industry and of course for professionals who use Adobe products, of course. In this case, up to 86.2% of the colors that a human eye can see are contemplated. Virtually all high-end monitors and mid-range cameras are capable of rendering this color space in full.ProPhoto RGB: This color space is the most complete, and is intended only for the most demanding professionals who want a reproduction of own color of the human eye. It covers 100% of the range of colors visible to the human eye, and is implemented by Kodak. It is supported by high-end cameras and it is recommended to use only in problems that support it, otherwise the image quality will be poor.

CMYK

This color space works with complementary colors to RGB, that is, cyan, magenta, yellow and black, hence the acronym in English. It is the most widely used color mode for printers and magazine and newspaper publishing professionals. So if you have something to print, the recommended color space is this.

This color space is the smallest of all due to the physical limitations of printers. It is ideal for them, since the colors they use are precisely these complements.

LAB

It is a color mode that is independent of the device and consists of three channels, in which the Brightness, A and B are controlled. This model is the one that is closest to the way our eye has of perceiving real colors. We can also connect it in Photoshop with the name of CIELAB D50 or simply CIELAB.

DCI-P3

This color space is newly created and is referenced by many professionally designed monitors optimized for multimedia rendering. This is because it is also a RGB based color space.

It is used in the projection of films and digital cinematographic content in the American film industry. This standard covers 86.9% of the human eye spectrum, and is of course geared toward HD video editing professionals.

One of the first displays to implement this color space was Apple's iMac with its famous retina display. There is also a specification called Ultra HD Premium that certifies devices with UHD (4K) resolution that are capable of representing at least 90% of the DCI-P3 color space.

Many devices implement certification for this color space, even smartphones like Google Pixel 3 have 100% DCI-P3 or the Asus PQ22UC screen, an OLED screen with 99% DCI-P3.

NTSC

NTSC is one of the first standards to be developed, back in 1953 when the first color televisions appeared. They occupy a relatively wide color space and that not too many monitors are capable of 100% rendering.

It is not a space that is already used too much, since it is oriented to analog TV, DVD movies and old console video games. However, it is used as a reference space to compare the performance of the image panels.

Rec. 709 and Rec. 2020

They are standards used for HD and UHD television respectively. It currently has a 10-bit color depth. Rec. 709 have a color space equivalent to sRGB for monitors.

For its part, Rec. 2020 is an evolution of the previous one and is aimed at UHD and HDR televisions that have a 10-bit color depth panel. This we can find it with the name of BT. 2020. Currently Rec.2100 with 12 bit color space is being implemented.

Delta E calibration

The expression Delta E or ΔE also appears at this point, which is the degree of calibration implemented by design-oriented monitors and which measures the sensation of the human eye to colors.

The human eye cannot differentiate colors to a Delta degree less than 3, although this varies depending on the range of colors. For example, we can differentiate up to a Delta E 0.5 on a gray scale, and instead in purple tones we will not be able to differentiate a Delta E 5.

• When we have a DeltaE = 1 we will have an equivalence between the true and the represented color, so the fidelity will be perfect. If the Delta E value is greater than 3, the human eye will be able to differentiate the sensation of colors between real and representation.

So when a monitor has Delta ≤2 calibration it will mean that the colors represented on it and the actual colors are will be able to be difference by our eyes.

This ends our article on what color space is and the most important concepts related to it.

We also recommend these tutorials:

Does your monitor have references to some of these color spaces? which? If you want to point out something or have doubts, write us in the comments.