In general, televisions and tele-media have really come a long way from its early days of greyscale screens and cathode ray tubes. Any program, movie, or show can now be experienced in all of its glorious details on the sleek and thin marvels of modern media technology- Televisions. But what gives the displayed picture all of its detail?… Or how does the TV even manifest an image, to begin with? We provide all the little details you need to know, as briefly as possible, to finally arrive at the answer to what is 4K TV.
What is 4K TV?
If the panel resolution is at least 8 megapixels or 3840×2160, with the ratio of the horizontal length of the panel to its vertical height equal to 16:9, it can be categorized as a 4k panel. Consequently, a TV with such a panel can be called a “4k TV”. However, the resolution at which a panel is called “4k” also changes with the panel’s different physical dimensions but usually is somewhat close to the numbers mentioned earlier. As far as screen technology is concerned, displays up to 10k have been invented; however, 4k is by far the most popular in the upper segments of the TV market. Henceforth, TVs that ship with a 4k panel, typically aren’t known to be easy on the bank but have superior picture quality in terms of sharpness, relative to more generic resolutions such as 1080p or 720p.
If this raises more questions in your mind than it has been answered. We have provided a ground-up explanation of the things you might need to know while keeping it as brief as possible.
4K TV – Pixel, Density, Resolution
To understand what a 4k TV is, we would first need to understand the meaning of a few simple terms in display technology, many of which you might already be aware of. So without further ado, let’s dive right into it.
Pixel: A pixel is a single unit of a display. Functionally, it is a tiny LED (in modern screens) that can change the colour of the emitted light when instructed to do so. Numerous pixels emitting instructed colours of light in synchronization makes up an image. Changing the image quicker than the human eye can perceive them discreetly, creates a moving image or video.
Panel: A display panel can be loosely thought of as a surface with numerous incredibly tiny cells, making up a grid. The grid spans the entire area of the “screen,” along with accompanying layers, electronics, etc. In each of these cells, exists a pixel. A panel is thus made up of rows of columns of these tiny pixels.
Resolution: It is the total number of pixels present on a screen. For a display resolution of 1080×1920, each row has 1080 pixels and each column, 1920 pixels. That brings the total number of pixels to 2073600 (or ~ 2 megapixels) throughout the entire screen.
Pixel Density: It is just the number of pixels present per unit area on a screen. It is typically measured in PPI (Pixels Per Inch). So if you could slice a 1 square inch area from the screen of your phone and it had, let’s say, 321 * 321 pixels, it would mean that your phone has a pixel density of 321 PPI.
Aspect Ratio: It is the ratio of the number of pixels present in a single row of the screen to the number of pixels in one of its columns. For, e.g., if your laptop screen has a resolution of 1920×1080, it would have an aspect ratio equal to 16:9.
Response Time: It is just the amount of time a pixel on your screen takes to change the color of the emitted light from one to the other (generally specified in milliseconds). Often, in spec sheets, a “GTG” value is mentioned. GTG means Gray-To-Gray and is the amount of time the same pixel takes to shift from one grey level to the next. Lower here is better as that means that your display as a whole is snappier when changing from picture to picture.
Now that we have a foundation on display technology’s basic terms let’s understand what a 4k display is. We would also briefly discuss what all you should be looking for in any particular display as well as HDR, and how it affects you.
A 4k display is one that has at least ~8 million active pixels. On a standardized aspect ratio of 16:9, saying a screen has a resolution of 3840×2160 and 4k is the same thing. But then what is 4k UHD or Cinema 4k or 2160p or DCI 4k? They are mostly the same thing with some slight variances or, most often, none at all. So, “Cinema” 4k and DCI 4k are the exact same- a resolution of 4096×2160. 4k UHD and 2160p are the exact same as 4k with a resolution of 3840×2160
The story actually doesn’t end here. In the real world, there are several varied factors to consider when looking into the display of a TV, perhaps in your wishlist. For example, the panel technology that your display sports are an essential factor to consider. TVs in the upper segment of the market often include OLED panels, which vary widely from more familiar technologies like IPS or TN in terms of the process through which they manifest a picture. OLEDs generally have excellent contrast ratio, fantastic response time, and color accuracy but are costlier. At the same time, IPS panels cannot display full blacks but are cheaper. So needless to say, if you have the money, OLED panels should undoubtedly be something you might want to look into.
The pixel density of the screen keeps on decreasing as the size of the panel is increased, keeping the resolution constant. The loss of sharpness in the displayed image is especially apparent for more generic resolutions such as 1080p (1920×1080) or 720p (1280×720). Thus 4k resolution also brings forth a significant amount of detail in the image in large screen TVs. However, it is essential to note that the content being displayed must also be 4k content for the full experience. Modern 4k TVs generally have some form of implementation of a UHD upscaler for the content which might not be true 4k. Upscaled low-resolution content does not look as good as true/native 4k content. This is because the very act of showing more information in an image entails that the extra data exists, to begin with, not the case for lower resolution content. That being said, 4k content is getting more and more popular each day. Major streaming services such as Amazon Prime, Netflix, Youtube, etc., have already added a large amount of 4k content ready for consumption.
Which brings us to the last topic in the scope of this article to answer your question as to what is a 4k TV – HDR. HDR is the acronym for High Dynamic Range, which is a bit confusing and often wrongfully interchanged with 4k. To set the record straight, 4k is not HDR. The basic idea of HDR is simply more image information in the content you are consuming. When decoded and displayed by a suitable HDR-compatible TV, the resultant is a more colour accurate and granular image. However, the said screen itself should be capable of displaying images with such granularity. That is certainly something to watch out for. It is not uncommon to find cheaper HDR-compatible TVs but with screens incapable of displaying the full range of the HDR content.
In conclusion, it is not uncommon to find 4k TVs in the more affordable price segments today. As display technology continues to reach new milestones and continues getting more affordable. However, the devil is always in the details. The answer to “What is a 4k TV?” is not as simple as a TV with a 4k panel when it comes to getting the most for what you pay for. If you are reading this after having read all those mentioned above, you now have the necessary knowledge to make an educated choice should you need to. Now that you know what is 4K TV, time to binge some of your favourite shows.