Introduction
Thanks to the variety of smartphones, tablets, monitors, laptops and TVs with dozens of inch, we have never had screens with sizes as different as today. Tied to this scenario is another characteristic also rich in options: the resolution. Terms such as HD, Full HD, 1080p, 4K, 8K, XVGA and others are increasingly becoming part of our “digital life”.
But, after all, what is resolution? What is the difference between HD, Full HD, 4K and the like? As is the relationship between screen size and resolution? If these and other similar questions pervade your mind, do not worry: in the next lines, the abbreviationfinder explains everything you need to know about the subject.
If you already know what is the size of the screen, resolution, pixel density and aspect ratio, you can use the following list to jump to the topic of your interest. But it is clear that the reading in full is are commended for easier understanding 😉
What is the resolution?
There are those who confuse resolution with screen size. Even if this is not your case, it is convenient to learn / recall how the measurement is made of a screen before we get to the explanation of resolutions.
Screen size (in inches)
In the universe of screens, there are two key measures that are related, but not equal: size and resolution. The first makes reference to the the physical size of the screen; the second, to the amount information that it is possible to view inside these physical limits.
By default, the size of the screen is measured in inches (inch, in English). Every inch is worth to stress, is the equivalent of 2.54 centimeters or 25.4 mm and can also be represented by the character in quotation marks, for example: 32″ (32 inches).
Every time you hear about a 6-inch smartphone or a TV of 40 inches, therefore, you know that the measure does reference to the screen size of the device. A tablet of 10″, for example, it indicates that your screen has 25,4 cm (10 x 25,4).
Only that this is information a both inaccurate, because the screens are typically rectangular, with this “rectangle” may have different ratios in the horizontal and vertical, right? Yes. That is why the measurement is made considering the diagonal of the screen.
In other words, we measure the size of the screen by calculating the distance in inches from the left-bottom corner to the corner the upper-right (or vice versa), as shown in the following figures:
Screen resolution
You already know that, by default, the screens have a rectangular format. This means that the area of these devices considers the width (horizontal) and the height (vertical).
It is here that we come to resolution: the image displayed on the screen is divided into tiny dots called pixels. You can understand a pixel as being the smallest size that an image can have.
The pixels are arranged in rows (horizontal) and columns (vertical). The resolution, therefore, is nothing more the measurement that indicates how many pixels there are in each row and in each column of the screen.
Thus, a resolution of 1920 x 1080 pixels indicates that the the screen is capable of displaying 1920 pixels per line and 1080 by column. It is like an array. A rule of thumb, the first number is a reference to the width; the second, to the height of the screen.
Note that this measure is also valid for images and videos. You can have, for example, a figure of 300 x 250 pixels or a movie of 720 x 405 pixels.
Relationship between screen size and resolution
You already know that the pixels are smaller information that a screen can display. Not to be that are reading this text on paper, you may be able to to distinguish them now approach well the eyes of the monitor or the mobile device with which you are accessing this page. But, why is there not a fixed measure for set the pixels?
Because the size of the pixels is not necessarily equal in all the devices. You can have two screens of 20 inches, for example, but a support resolution up to 1600 x 900 pixels, and the other, the same having the same physical dimensions, works with resolution maximum of 1366 x 768 pixels. If you try to do view a resolution higher than the supported, the device will not work correctly.
Each pixel supports a color, that is, information. Soon, the more pixels there are, the more detailed and rich will be the the image, because the more information the screen can view. Therefore, the monitor that has 1600 x 900 pixels can be considered better than the second for certain applications.
The image below is an example that compares the same image in different resolutions. The photo on the right, that has 300 x 225 pixels, is displayed in a more detailed way that the figure to the left, that has 160 x 120 pixels.
Pixel density (PPI)
All that well screens can be compatible with different resolutions, even so, is not strange that a monitor 20 inch supporting resolution maximum of 1366 x 768 pixels and a Apple iPhone 6, for example, be able to 1334 by 750 pixels fit within a screen of 4.7 inches? I mean, considering the due proportions, this difference should not be much greater?
What happens is that, with the evolution of the technology, the screens of the current now bear resolutions becoming larger, having dimensions reduced. It is as if the pixel had been so small to the point of being (almost) impossible to distinguish it with the eyes.
In the case of the iPhone and other Apple products, this is due to a technology that the company is commercially called of the Retina. It is a technique that allows the retrieval of pixels so small (78 micrometers on the iPhone 4 and 86 on the iPad 3, for example) that the effect obtained is equivalent to the existence of four pixels where before there was one.
This dynamism the whole of causes to consider a pixel as the smallest information displayed on a screen to miss a bit of sense, especially on mobile devices: more than resolution in and of itself, the notion of quality passes considering how hard it is possible to distinguish the points on the screen.
To do so, by convention, is to consider the density of the pixels. This is done by means of the measure PPI, which stands for Pixel Per Inch or, in good Portuguese, Pixels per Inch.
The higher the PPI, the better the quality of the screen: if there are more points, but the physical dimensions do not change, you can then include more detail there.
This aspect may not make much of a difference in large screens, such as TVs, but has enough relevance in laptops, tablets and smartphones, since we use these devices so much closer to the eyes. The already mentioned iPhone 6, for example, has the screen with 326 PPI.
It is important not to confuse PPI with DPI (Dots Per Inchor Dots-Per-Inch). This last measure is similar, but it is commonly applied in printing activities.
Aspect ratio (or screen aspect Ratio)
There is another feature of very important related to the screens: the ratio that determines how wide these are. Some screens have more format “square”, although there will actually be. Others are more “stretched out”, referring to the large screens of the cinemas.
As this factor can influence the display of images, videos, and even in the resolutions, the the industry works with standards pre-determined formats: the aspect ratio or screen aspect ratio.
Until a short time ago, especially in the time of the televisions and CRT monitors, the most common was the 4:3 format. This this means that, for each of the four equal parts of width, the screen has the other three of the same proportion in height. By dividing this number, we have 1.33 in, as well, this result can also be used to describe the format, although it is not usual.
Currently, the aspect ratio is 16:9: repeating the formula, for each of 16 equal parts in the width, there are other 9 of the same size in height.
This is a wide format, or wide screen, and if became more common in the market. But there are others, although most it is little used:
- 3:2
- 4:3
- 5:4
- 14:9
- 16:9
- 16:10 (or 8:5)
- 17:9
- 21:9
Note that the aspect ratio must match the resolution. A 4:3 screen, for example, not will be filled in properly if you work with 1600 x 900 pixels.
Patterns of resolutions
The industry also saw the obligation to adopt patterns of resolutions. Among other reasons, this is due to the use of this aspect to indicate the image quality: in theory, the higher the resolution, the better the quality, as you already know.
It is at this point that come on the scene designations such as Full HD and 4K. What do these terms mean, since they do not inform explicitly what the resolution of the screen?
So that you can understand, the main resolutions are explained in the topics following, one at a time.
VGA resolution and their variations: QVGA, HVGA, WVGA and FWVGA and other
VGA (Video Graphics Array) is a standard output of video created in the 1980s. It was the main format of the type in the market for a long time, until you lose your space increasingly, standards are more sophisticated, such as DVI and HDMI.
One of the several characteristics for this pattern is the use of the resolution of 640 x 480 pixels, the reason why this combination was known as VGA resolution.
From the years 2000, began to emerge phones and other mobile devices whose screens were VGA only as a reference and, thus, were based on resolutions considered variations.
One of them is the QVGA (Quarter VGA), which has 320 x 240 pixels. One of the devices based on this resolution is the Sony smartphone Xperia X10 mini. A variant of this is the WQVGA (Wide QVGA), which has greater width but keeps the height: 400 x 240 pixels.
To adapt to certain devices, the VGA itself is also left versions “extended”. One of them is the WVGA (Wide WVGA), 800 x 480 pixels and has been used by example, on the devices Google Nexus One and the Samsung Galaxy S.
Another is the FWVGA (Full Wide VGA), that expresses the resolution of 854 x 480 pixels and has been used in the smartphone Motorola Droid, for example.
At this point, it is convenient to remember that all of these resolutions tend to have small variations to suit the aspect ratio of a device. The WVGA, for example, you can have 720 x 480 pixels to fit the screen with 16:10 aspect ratio.
The list below shows a summary of the resolutions VGA, including some variations not mentioned.Do not be alarmed with the amount, nor do they worry about to decorate them. Most of it is little used, so just refer to pages like this to know the resolution each one represents:
- VGA: 640 x 480 pixels;
- WVGA: 800 x 480 pixels;
- FWVGA: 854 x 480 pixels;
- QVGA: 320 x 240 pixels;
- QQVGA: 160 x 120 pixels;
- HQVGA: 240 x 160 pixels;
- WQVGA: 400 x 240 pixels;
- HVGA: 480 x 320 pixels;
- WVGA: 800 x 480 pixels;
- SVGA: 800 x 600 pixels;
- DVGA: 960 x 640 pixels;
- WSVGA: 1024 x 600 pixels.
XGA resolution and similar: WXGA, SXGA, UXGA and other
The XGA (Extended Graphics Array) has emerged in the 1990 as a complement to the specifications of the VGA and Super VGA. With regard to the resolutions, this default is used to indicate the combination of 1024 x 768 pixels, which for a long time, it was very common on the screens at the 4:3 format.
Here also there are variations of the more “extended” and properly call of WXGA (Wide XGA). This name can refer to at least six resolutions:
- 1152 x 768 pixels;
- 1280 x 720 pixels;
- 1280 x 768 pixels;
- 1280 x 800 pixels;
- 1360 x 768 pixels;
- 1366 x 768 pixels.
The Google Nexus 4 is an example of a smartphone that uses a WXGA resolution, in this case, the combination of 1280 x 768 pixels.
There is also a version called XGA+, which represents the resolutions of 1152 x 900 and 1152 x 864 pixels.
The following is a summary with all (or almost all) the variations of XGA. Again, don’t worry about memorizing them:
- XGA: 1024 x 768 pixels;
- WXGA: 1152 x 768 the 1366 x 768 pixels;
- XGA+: 1152 x 900, 1152 x 864 pixels;
- WXGA+: 1440 x 900 pixels (there are differences of opinion as the existence of this resolution);
- SXGA: 1280 x 1024 pixels;
- SXGA+: 1400 x 1050 pixels;
- WSWGA+: 1680 x 1050 pixels;
- UXGA: 1600 x 1200 pixels;
- WUXGA: 1920 x 1200 pixels;
- QWXGA: 2048 x 1152 pixels;
- QXGA: 2048 x 1536 pixels;
- WQXGA: 2560 x 1600 pixels.
Here, you may want to mention that, in a certain way, the resolutions that have 720 pixels or more can be considered High Definition(HD). You will understand the why in the next topics. Before that, it is valid to know the variations of “very high definition” XGA:
- QSXGA: 2560 x 2048 pixels;
- WQSXGA: 3200 x 2048 pixels;
- QUXGA: 3200 x 2400 pixels;
- WQUXGA: 3840 x 2400 pixels;
- HXGA: 4096 x 3072 pixels;
- WHXGA: 5120 x 3200 pixels;
- HSXGA: 5120 x 4096 pixels;
- WHSXGA: 6400 x 4096 pixels;
- HUXGA: 6400 x 4800 pixels;
- WHUXGA: 7680 x 4800 pixels (whew!).
HD resolution (720p)
Before the advent of mobile devices with screens sophisticated and TVs LCD, LED, Plasma and the like increasingly large, the market has adopted a resolution standard not only to decrease the problems in the display of content on these devices as also to submit an appeal heavily commercial. Is there arises what we know as HD resolution, acronym for High Definition (High Definition).
The HD refers to the resolution of 1280 x 720 pixels, which in turn combines with wide screens (16:9). In general, the images that comply with this resolution have quality quite satisfactory.
The HD became, in fact, a reference in the market that can be found in TVs cost low and intermediate, as well as in smartphones and tablets. You just need to take care to not to be confused with its two variations: the nHD, which has 640 x 360 pixels and qHD with 960 x 540 pixels.
720p and 720i
Another factor that has resulted in the emergence of HD resolution is the standard HDTV (High-Definition Television or, in the Brazil, High-Definition TV), which determines a set parameters to replace television systems traditional, such as NTSC and PAL. Among these criteria is the association of the resolution of 1280 x 720 pixels with aspect ratio of 16:9.
At this point, you might have already understood: the term 720p, that is used a lot, is also a name that indicates the resolution of HD, this it is, of 1280 x 720 pixels. But, where is gone this letter ‘p’?
The human eye does not perceive, but the content of the TV it is updated several times per second. This process it is called Refresh Rate or Refresh Rate and, typically, is measured in Hz (Hertz). A TV with 60 Hz, and example, renews its image 60 times per second. Theoretically, when the greater this number, the more “comfortable” is the the display of an image on the screen.
It is from here that comes the ‘p’. The letter makes reference to the the technique of Progressive Scan (Progressive Scan), that it is also one of the parameters of HDTV. The term indicates that the refresh of the screen happens at all the lines of this, from top to bottom, that is, all of the content displayed it is renewed in a step only.
It may seem a little obvious, but it is that systems TV older use the Interlaced Scan (Interlaced Scanning), where the update happens in a similar way, but the first lines pairs are updated, then the odd lines, in a type schema “other line”.
The Interlaced Scan is represented by the letter ‘i’, therefore, can there is also the standard 720i. But, there is no record of official use of this term, because the current technology supports 720p even in very simple devices, and there is reason for the adoption of the interlaced mode.
It is worth noting that the patterns that do not reach the specifications HDTV tend to fit in characteristics of the SDTV (Standard-Definition TeleVision). The their most common resolutions are 704 (or 720) x 576 pixels, 704 (or 720) x 480 pixels.
Full HD resolution (1080p)
If the HD is already resulting in images that are very good, the Full HD appears to make the experience even more enriching. The term, which can also be abbreviated as FHD (although this acronym is little used), represents the resolution of 1920 x 1080 pixels, equally (or more) appropriate to the proportion of 16:9.
Such as the HD, the Full HD has gained strong commercial appeal, something in the style “the HD is good, but the Full HD is much better”. Equipment a little bit more sophisticated are the target of this type of display, such as in the case of smartphones, the Motorola Moto G4 and the Google Pixel, in addition to monitors and TVs of various sizes, of course.
1080p and 1080i
The Full HD resolution is also recognized in the specifications of your HDTV and, consequently, receive a designation oriented to the amount of lines in Progressive Scan: 1080p. So, you already know that a device that sports this name on your specifications it is Full HD.
Although not very common, it is possible to still find devices 1080i: your screens support Full HD resolution, but with the update in mode Interlaced Scan.
Summary
Resolutions HD and Full HD has become a reference in the market, which is very useful because this aspect reflects in the standardization of the formats of the videos and pictures, for example, as well as facilitates the the life of the consumer, that is not lost in the midst of so many the possible resolutions. As shown in the summary following, the variations are few:
- HD (720p): 1280 x 720 pixels;
- nHD: 640 x 360 pixels;
- qHD: 960 x 540 pixels;
- Full HD (FHD, or 1080p): 1920 x 1080 pixels;
- QHD (WQHD): 2560 x 1440 pixels.
As the minimum amount of vertical pixels for a resolution to be considered high definition is 720, created informally on the understanding that any value above that is HD. Does not cease to be correct, but for a product to receive this acronym or the Full HD needs to respect the resolutions are defined for each standard.
4K Resolution (UHD or 2160p)
We are still enjoying our devices to Full HD, but the the industry wasted no time and has already become a reality a standard higher — four times higher, in fact: the 4K resolution, which represents the generosíssima combination of 3840 x 2160 pixels.
Also called Ultra HD (UHD), the 4K resolution began to be standardized in 2003, going to be used for in earnest in mid-2006, by the cinema. A few years later, however, already it was possible to find screens UHD on televisions more sophisticated and costing a few thousand dollars.
It is relatively difficult to find a screen 4K that has less than 50 inches of size. The reason is that, at least until the moment, only larger pieces of equipment manage to combine technical feasibility of construction and quality of image optically superior.
That is why, while smartphones with 4K have already been promised, a lot of people see the idea with suspicion: in screens small, the differences between Ultra HD and 4K can hardly be noted.
Like in the other standards, the 4K resolution also has its variations. The combination of 3840 x 2160 pixels is taken with the main because it is the resolution existing in the specifications of the Ultra HD Television, also known as UHDTV. Thus, we can also use a name that makes reference to the extent vertical Progressive Scan: 2160p. Only, contrary to the terms 720p and 1080p, the name 2160p not it is very used.
Another resolution which is also represented by the acronym 4K (but not by the UHDTV) is the 4096 x 2160 pixels, which was adopted officially by the Digital Cinema Initiatives (DCI), entity formed by the major companies of the industry film to determine the standards for the segment.
In fact, it is in the cinema resolution of 4096 x 2160 pixels better fulfills its role, because this combination is more appropriate screens or projections with aspect ratio of 17:9 existing in rooms more modern, while the majority of the TVs that attaches to the 16:9 aspect ratio. Because of this difference, the resolution of 4096 x 2160 pixels also tends to be call DCI 4K.
Here are the main variations:
- 4K (UHDTV, or QFHD): 3840 x 2160 pixels;
- 4K (Ultra Wide HDTV): 5120 x 2160 pixels;
- DCI 4K: 4096 x 2160, 4096 x 1716 (unusual) and 3996 x 2160 pixels (also unusual).
For the letter ‘K’ in 4K?
As well as HD and Full HD, the term 4K does not only makes reference to a resolution, but it also has strong commercial appeal. But, if the default can also be called Ultra HD or UHD, the 4K is the expression more used?
It happens that the letter ‘K’ is, in the International System of Units, used to represent the number 1000. In Brazil, this as it is not very common, but the United States (and other countries) use quite. So, if you have 2 thousand or 3 thousand units of anything, you can call this amount of 2K or 3K, for example.
As the horizontal resolution of UHDTV is a number that approaches 4000 (and exceeds, in the case of the DCI), it is assumed that the acronym 4K started to be used to represent it because it conveys a clearer sense of your awesomeness.
Here, it is worth observing that the existence of the 4K does not mean that the HD and the Full HD will be delegated to the past, at least not for a good long time. These standards have quality satisfactory on mobile phones, tablets and even televisions.
In addition, the 4K has some disadvantages. For to start, the amount of content in this format still it is small, although there are now films, broadcasts sports events and even support UHD services like YouTube.
Another possible disadvantage is that streams 4K require connections to the Internet for extremely fast, which it is not yet a reality for a lot of people, even in developed countries.
Resolution 2K
From the commercial point of view, we jump from the Full HD video direct to the 4K, but there is an intermediary here: the resolution 2K. Not only is this very common to find devices that bearing a stamp with this name.
The main reason for this is that the 2K references the resolution of 2048 x 1080 pixels. As this the combo is only a little greater than Full HD (1920 x 1080), for the industry was more interesting from straight to 4K.
Here also there are variations:
- 2K: 2048 x 1080 pixels;
- DCI 2K: 2048 x 858 or 1998 x 1080 pixels.
Resolution 5K
In the second half of 2014, the market began to see the arrival of the few, but interesting products with resolution 5K. The line of monitors, 27 inch UltraSharp, Dell, is an example.
The denomination 5K makes reference to the resolution of 5120 x 2880 pixels (it is a little bigger the combinations 4K, therefore) and can work with screens aspect ratio 16:9 or proportions near this.
Resolution 8K (FUHD or 4320p)
To display images four times higher than Full HD, the 4K resolution is astounding enough to there need for anything more advanced, right? The resolution 8K comes to prove that the the answer is “no”.
It may also be the call of the Full Ultra HD (FUHD) or 8K UHD, the resolution 8K defines a combination of 7680 x 4320 pixels, making it 16 times greater than Full HD (remembering, 1920 x 1080 pixels). Not understand how? Note the following illustration:
Screens 8K are still being developed, so there are very little new equipment compatible with that resolution. Either way, the format should cover both cinema screens and televisions. Not for less, the resolution of 8K is also recognized by the specifications of UHDTV, which gives it the name 4320p.
Here — guess what — there are also variations in resolutions, but each one of them is directly linked to an aspect ratio different:
- 7680 x 4320 pixels: 16:9;
- 8192 x 4320 pixels: 17:9;
- 8192 x 5120 pixels: 16:10 (or 8:5);
- 10080 x 4320 pixels: 21:9.
There is still a resolution that the unusual call of 8K Full dome which has 8192 x 8192 pixels. Its use is directed the projection equipment used in planetary, for example.
The forecast is that the screens and content 8K only begin to arise on a regular basis by around 2020. The main company that bet in this standard is the Japanese NHK, which calls the resolution of Super Hi-Vision (SHV). The challenges for its implementation are really great: currently, the benefits of a resolution so high only appear on TVs with more than 80 inches.
Ending
In the midst of so many resolutions, you may be pergutando: which is the best? Well, it depends. For those who will buy a TV, there are already vast content offered in HD or even in Full HD from Blu-rayor online services such as Netflix, for example.
Fortunately, the majority of tvs current work with these resolutions. There is already something also in 4K — including smartphones like the Samsung Galaxy S7 are already able to record videos on this— resolution, but the TVs that exploit this characteristic are nothing but cheap.
For smartphones, the situation is much more pleasant: in most of the times, a resolution based on some standard HD or Full HD gives the job.
In general, the tip is this: analyze all the factors that lead to the best cost-benefit relation. In the current scenario, it is not always the higher resolutions sofiscadas fit in this context.
