Differences between Coverage and Volume of a Color Space on Screens

Coverage and Volume of Color Spaces

When are we going to buy a device that includes a screenwe have to look at many aspects if we want to choose the best one for our use. Size, resolution, refresh rate or even refresh rate are very popular terms and that we always look closely, but there are also terms like coverage, volume and color range. In this guide we are going to tell you all about volume and color coverage.

Whether it’s a mobile phone, a laptop or a new monitor, these terms Coverage, Volume and Color Gamut are important to keep in mind. But let’s not be fooled with marketing strategiesmanufacturers sometimes take advantage by indicating values ​​that are not correct to try to attract the attention of consumers and make them believe that their devices are the ones that best coverage values ​​and volume of color have.

For this we will have to differentiate between these three terms that can lead to confusion, let’s see what each one means.

• Gamut (or gamut) of color. This term comes to represent the different available color standards that a screen can represent. Some are more demanding and cover more colors than others. The main ones are sRGB, Adobe RGB, DCI-P3 and NTSC.
• color coverage. This term indicates the percentage that that specific screen is capable of reproducing over a certain range of color. Thus we can find that a screen can represent 100% Adobe RGB and at the same time 80% DCI-P3.
• color volume. Color volume indicates the total percentage of colors that a screen can reproduce. A color volume of 130% over Adobe RGB indicates that it is capable of reproducing more colors than Adobe RGB indicates in its full color gamut.

With these clarified terms we can deny some strategies that manufacturers have to make us believe that their devices, in this case screens, are capable of reproducing the greatest number of colors.

The truth about Color Volume Coverage

We must not confuse these three terms from before, above all we must differentiate well Color Coverage and Color Volume. These terms can be misleading, as a screen you will never be able to reproduce more than 100% color coverage of a particular color range. For example, we cannot say that a screen is capable of reproducing 120% color coverage of the sRGB range, since it is impossible for it to reproduce more than 100%, which would cover all possible colors within sRGB.

If it is true that, as we have indicated before, it can reproduce a higher percentage of color volume than sRGB. Let’s get this straight, a display can be capable of reproducing 100% of the sRGB gamut but also represent more colors than are included in the sRGB gamut. So, for example, this screen could represent up to 130% of color volume of sRGB that can be divided into 100% of the sRGB gamut and an extra 30% of colors that are not included in this gamut.

In the same way this 130% of color volume can represent 90% of color coverage from another range with a greater number of colors, such as DCI-P3. It is common to find in the characteristics of the devices that they are measured with several ranges. We can see 130% of color volume of sRGB and 90% of color coverage of DCI-P3. But what we can never find is more than 100% color coverage of any range, this is a cheated.

We also have to take into account that the color volume It does not have to refer in its entirety when it is capable of exceeding this 100%, it is possible that a device can only represent 80% of sRGB and an extra 50% of other colors not included in sRGB, this would be a total of 130% of color volume of sRGB but not 100% of color coverage of sRGB.

Most Important Color Spaces

Let’s see the different color ranges and how the coverage and/or color volume of each device is measured. These ranges of colors are generally represented on the CIE 1931 chroma chart where the colors that can be perceived by the human eye are represented. These colors are generally divided in RGB for Red, Green, Blue or Red, Green and Blue. Through these colors we can form many others that we can perceive with our eyes.

In this way, the different ranges of colors that we will see here can be represented by an XYZ coordinate system on the CIE 1931 chromacity diagram. Each point represents one of the three primary colors that coincide with the color receptors of the human eye, forming a triangle that represents the color coverage that each range will have with respect to this diagram.

Therefore, when a color measurement is made on a screen, volume can be greater than coverage, but never the other way around. The triangle formed can cover more colors than those included in a range of colors in one area, but in another area it can be the same or less.

sRGB or standard RGB

This Standard RGB (or sRGB) color space is the most widely used, it is also the oldest since it was designed to match the colors of old CRT monitors. We can find a multitude of screens that measure their color coverage with this range, since it is the one that covers fewer colors.

It is said that any 8-bit image with 8 bits per channel can be represented with sRGB, so it is not a very efficient system when it comes to representing real colors. Thus, the specialized industry demanded other ranges of colors where the color coverage It covers many more colors.

Its representation in the CIE 1931 chromaticity diagram is very close to the extremes in blue and red colors, but with a vague representation of the color green. Point D65 representing the white color is located at 0.3127-0.3290. Specifically, we find the red point at x=0.64 and y=0.63, the blue point at x=0.15 and y=0.06 and the green point at x=0.3 and y=0.6.

AdobeRGB

color space AdobeRGB It was born because the RGB (sRGB) standard did not cover enough colors for the professional environment. Adobe RGB was created by Adobe in 1998 with the intention of reproducing the CMYK colors widely used in the imaging industry as best and as faithfully as possible, but adapted from an RGB color space that is frequently used in monitors and cameras.

This space aims represent truer colors and cover at least 50% of the visible colors, but it was very advanced for its time. As technology has advanced, it has been use this range of colors more oftenespecially in monitors and devices aimed at image and video professionals who need to reproduce real colors more faithfully.

For this range of colors, the points have been placed with greater representation of the color green relative to sRGB. Exactly we find the points, with respect to the CIE 1931 chromacity diagram, of the red color at x=0.64 and y=0.33, of the blue at x=0.15 and y=0.06, and of the green at x=0, 21 ey=0.71. Leaving the white color or also called point D65 at x=0.3127 and y=0.3290.

DCI-P3

This range of colors was developed by film industry experts in 2005. DCI-P3 (Digital Cinema Initiatives) is very similar to Adobe RGB, but it has a slight change in the green hue, being very similar in blue and red. DCI-P3 is capable of represent up to 45% of CIE 1931 colorsfor this reason it is widely used in professional environments for video.

Full DCI-P3 color coverage is a good guarantee that we will be able to reproduce a large number of colors that the human eye can also appreciate, with a great resemblance to real colors as we see them.

With this range of colors, the points located with respect to the CIE 1931 chromaticity diagram are for red x=0.68 and y=0.32, blue x=0.15 and y=0.06 and green x=0.265 and y=0 .69. Leaving point D65 at coordinates x=0.314 and y=0.351.

NTSC

This range of colors belongs to the National Television Standards Committee (or National Television Standards Committee) in the United States, which create your own range of colors to differ slightly from Adobe RGB in the Red and Blue colors. This range of colors is very used in monitors for professional video and photography.

Here we find that the points, always with respect to the CIE 1931 chromacity diagram, are in red x=0.63 and y=0.34, blue x=0.155 and y=0.07 and green x=0.31 and y=0.595. Leaving its point D65 at x=0.3127 and y=0.3290.

this color space not so widespread like the rest, but it has earned its place especially in products aimed at professionals.

don’t be fooled

With all this information, you will be able to know what Color Coverage, Color Volume and within what color range they are able to represent colors of the device you are interested in. If you see that a device has a color coverage of 130% you can mistrust and think that it refers to the color volumewhich as we have indicated before it can mean that it meets 100% Color Coverage or that it is less.

For professional environments you should opt for a color coverage 100% of some gamut that best represents real colors, be it DCI-P3 as the most extended or NTSC. If you are going to work with images related to Adobe, you can choose one broad or full color coverage in the Adobe RGB gamut.

However, if our purpose is not to have the most realistic colors possible, although with a good representation of them, we must opt ​​for a good sRGB coverage and even with a color volume above, but within this volume make sure that the color coverage be high to have a consistent image quality.

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