What is WCG (wide color gamut) & color volume in a TV?
A display is considered to have a wide colour gamut when it can reproduce a broad range of colours and accurate shades, allowing scenes to appear more lifelike and realistic.
This capability is a property of the display itself and depends on the technologies and enhancements incorporated into the panel.
Although wide colour gamut (WCG) is different from HDR, the two technologies complement each other closely.
In this article, we will explore WCG in greater detail and understand how it relates to the colour volume of a display.
What does WCG do different from HDR?
WCG, or wide color gamut, is a term often used with HDR.
HDR increases the dynamic range of the picture by increasing the contrast and color accuracy. It tries to make the whites even whiter and the blacks darker.
WCG goes a step further towards making the picture more realistic by producing more and better colors. It makes the ‘reds’ redder, ‘blues’ bluer and ‘greens’ greener.
In simple words, it improves the picture quality by displaying more and deeper colors.
What is the need of having WCG on TV?
You shouldn’t have imagined that our eyes can see billions of colors.
For instance, take a look at the following picture of a parrot sitting over the branch of a tree. Try to count the number of colors in this picture.
Now, the question is: How many colors can your TV display?
If your TV can’t display those many colors that can be seen through our naked eyes, the picture quality on that TV wouldn’t be as realistic as what our eyes can see.
As simple as that.
So, to make the picture appear more realistic, more colors are needed, which can be achieved through a wide color gamut.
What is color gamut?
The word ‘gamut’ means the entire range of something. Similarly, the color gamut of a device refers to the range of colors it can reproduce.
Each device, like a printer, scanner, camera or monitor, is designed to display a certain range of colors.
This range is essentially a certain area of the visible colour spectrum that the device can reproduce at the output, also known as the color gamut of the device.
The color gamut of a TV can be defined as the range of colors it can display. In other words, the total number of colors that can be displayed on a TV screen is called the color gamut of the TV.
The wider the color gamut of a TV, the more colors it can display.
What is color volume?
Color volume refers to the complete range of colors a display can produce across different brightness levels.
It depends not only on the device’s color gamut, but also on its contrast ratio and peak brightness.
Displays such as QD-OLED panels, which offer excellent contrast, high brightness, and a wide color gamut, are capable of delivering exceptionally large color volumes.
In other terms, color volume describes how well a screen can maintain rich and accurate colors from the darkest shades to the brightest highlights.
Let’s understand it in more detail.
You must be knowing that the term “volume” relates to any 3-D space. Similarly, color volume means the total amount of color in a 3-D color space.
But how is that space created? Let’s explore.
We have only talked about color gamut till now, by which we have referred to the 2-D color space.
But we haven’t talked about the brightness or luminance of colors yet.
Bright red, dark blue, dull yellow, etc., are some of the terms that refer to colors with different brightness levels.
A shade of green at 500 nits will look different from the same shade of green at say, 50 nits of brightness.
If we introduce a dimension of brightness or luminance in the color gamut, then we get what is known as color volume.
Or, you can simply understand that we are adding an extra dimension to the 2-D color space so that it becomes a 3-D color space or color volume.
Here, the peak brightness plays a very important role. If two TVs have the same color gamut, the one having higher peak brightness will have higher color volume.
What is the significance of color volume?
A picture scene contains a wide variety of colors appearing at different levels of brightness.
A TV with a large color volume can display each color of the scene at the specified brightness level to bring out even minute details.
This, in turn brings out the true essence of HDR and the true intention of the content creator.
The TVs having wide color gamut and high peak brightness have the highest color volume. Therefore, they display accurate and vibrant colors resulting in an extraordinary HDR performance.
If you notice the above images closely, the second image has more saturated colors and clearer highlights.
This is because the colors are displayed at the perfect brightness levels and in the accurate shades in each part of the image, be it the sky, the clouds, the mountains, the trees or the road.
This image owes this to its large color volume which makes it more realistic with vibrant and punchy colors.
So, it is now imperative to buy a TV with a wide color gamut and high peak brightness, consequently a high color volume.
In fact, you should buy a true HDR TV with WCG for the ultimate viewing experience.
WCG vs sRGB vs DCI P3 vs Adobe RGB
sRGB and DCI-P3 are types of color gamut standards, but DCI-P3 offers a much wider range of colors.
That said,
There’s no single definition of a perfect wide color gamut — what qualifies as ‘wide’ depends entirely on the reference standard being used.
sRGB is limited to a color depth of 8-bits, displaying around 16.7 million colors, whereas DCI-P3 supports 10-bit color, enabling up to 1.07 billion colors—roughly 64 times more than sRGB.
In addition to this significantly higher color count, DCI-P3 delivers richer and more vibrant shades in reds, blues, and greens, resulting in more realistic and visually appealing images.
Because of its broader and more saturated color reproduction, DCI-P3 can be considered a wide color gamut standard.
Similarly, Adobe RGB also provides a color range comparable to DCI-P3, though each of them performs better in different areas of color reproduction.
Both DCI-P3 and Adobe RGB can be classified as wide color gamuts due to their extensive color coverage.
In contrast, sRGB, with its narrower range and comparatively limited color depth, can be regarded as a more basic color gamut standard.
Which is the widest color gamut standard?
Rec. 2020 or BT.2020 is probably the widest color gamut till date, covering more than 75% of the CIE color space.
It includes almost all the colors that the human eye can perceive and distinguish. This makes it significantly wider than DCI-P3, which is currently the standard color gamut used in most high-end displays.
However, Rec. 2020 is not yet fully utilized by modern displays because it requires much higher color depth and content mastered specifically to take advantage of its full capabilities.
Most HDR content does not contain enough color information to benefit from such a wide gamut.
Therefore, Rec. 2020 can be considered a future-ready color standard. As advanced display technologies such as micro-LED and QDEL become more mainstream, they will be able to utilize much more of the potential offered by this expansive color gamut.
Is WCG in TV worth it?
Is WCG necessary to have better picture quality or is it just a marketing gimmick?
Sure, the improvement with WCG may not be as pronounced as it was when HDR was introduced. But still, if you are a keen viewer, you will notice the difference when you compare two TVs, with and without WCG side by side.
In future, content creators may start using a very wide color space to craft content. Then, your TV will need to have a large color gamut like the Rec. 2020 to display the content to the fullest.
Otherwise, you may miss out on a significant color volume carried by the content if your TV has has a smaller color gamut like the sRGB or the Rec. 709.
So, why not make your TV future-proof with more and better colors?
FAQs
Here are some frequently asked questions about the wide color gamut.
1. Which is the best color gamut for gaming?
The best color gamut for gaming and watching movies, as per today’s scenario, is DCI-P3, which has 10-bit color depth and displays deep, saturated and vibrant colors.
2. What is the difference between color gamut and color volume?
Color volume refers to a 3-D color space created by combining a dimension of luminance with a 2-D color gamut.
3. What is the difference between HDR and WCG?
HDR expands the dynamic range of the picture by introducing more contrast and color accuracy while wide color gamut introduces deeper, more vibrant and more number of colors in the picture.
Both HDR and WCG attempt to make the picture quality more realistic.
4. Is it possible to have a wide color gamut without HDR?
Yes, because HDR is related to contrast and the number of luminance levels while wide color gamut is related to the number of colors.
However, WCG without HDR is not that worthwhile because, despite having a good number of colors, they may not be displayed at the required brightness levels and, thus, may not reproduce the same colors that should be displayed for a realistic viewing experience.
