Frequently Asked Questions

 

 


Q. What Should I Look For In The Quoted Specification?

A. The first thing to realise when buying a new screen is that you can't always rely on quoted specifications. These are often exaggerated for marketing purposes, and are commonly based on different measurement techniques and varying benchmarks between each manufacturer. As a guide and general rule of thumb:
 

  • The lower the response time the better. Be aware of ISO response time figures and grey to grey (G2G) transition figures as you will need to understand the difference. Screens with a G2G quoted response time use ‘Response Time Compensation’ (RTC) technologies, sometimes referred to as overdrive. These technologies are used to boost pixel response times and in practice can make quite a lot of difference. This is particularly important with non-TN Film panels (i.e. IPS, PVA, MVA etc)

  • The higher the contrast ratio, the better. This will also help indicate the black depth of the screen and how well the screen can handle differences between light and dark content. Be wary of dynamic contrast ratio figures being quoted nowadays and you will need to understand what the difference is between those and the ‘static contrast ratio’. Nowadays you will see static contrast ratio figures ranging up to ~5000:1 in some cases. DCR can range up in the millions:1 but are massively exaggerated. Make sure you understand which contrast ratio figure is being quoted in a spec and ideally read a review where it is really tested.

  • The wider the viewing angles the better. Be wary of how they calculate their figures. Sometimes they will try sneaking things like listed them when CR > 5 instead of when CR > 10 to inflate their numbers. Again real life performance might not match quoted specs. You will normally see TN Film panels listed with a 170/160 viewing angle (a classic indication that the screen is using TN Film technology by the way). IPS, PVA, MVA and PLS panels will normally feature a 178/178 viewing angle spec, but in reality the performance does vary.

  • Perhaps the most important 'spec' to consider if the panel technology being used in the monitor. This is not always provided but if in doubt you can use our panel search tool to identify a particular model's panel technology.


I would really recommend reading further into the details about monitor specs before you make your purchase so you can understand what they infer about the monitors performance characteristics.

 


Q. What Is the Best Panel Technology To Get?

A. A very important thing to consider is what panel technology the screen uses you are interested in buying. While specs may look similar on paper, performance may vary quite considerably between the models due to the underlying panel technology used. The most common technologies used in the desktop monitor market are TN Film, IPS, MVA and PVA (and various variations thereof). More recently in 2011 Samsung also introduced a new technology called PLS which, while in its infancy, is designed to compete with the popular IPS technology. These are all produced by a range of panel manufacturers and offer a variety of strengths and weaknesses. There is a reasonable amount of talk about panel technologies with many people quick to jump on a bandwagon and claim one is superior to another. To be honest, they all still have their place in the modern market, and due to their different characteristics, can play a key part in finding the right monitor for your use.

There are various generations of each technology as well, and different manufacturers have slightly different names for their versions. Look out for
 

  • TN Film (Twisted Nematic + Film) = pretty uniform in naming, developed by many manufacturers including all the larger suppliers

  • IPS (In Plane Switching) = S-IPS, H-IPS, e-IPS, AS-IPS, AH-IPS, p-IPS, generally all developed by LG.Display

  • MVA (Multi-domain Vertical Alignment) = S-MVA, P-MVA, AMVA, generally developed by AU Optronics and some from Chi Mei Innolux (formerly CMO)

  • PVA (Patterned Vertical Alignment) = S-PVA, cPVA, a Samsung technology exclusively manufactured by them

  • PLS (Plane to Line Switching) = S-PLS, a Samsung technology exclusive to them


For more information about panel technologies, see this detailed article which is often updated.

 


Q. What Specs Should I Be Cautious Of?

A. There are quite a few specs which are either massively exaggerated or need caution. Here are some which you need to be aware of:

  • Dynamic contrast ratios - perhaps the most overly exaggerated specs in the modern market. You will see figures in the millions now, but these are largely meaningless. Dynamic contrast ratios involves controlling the backlight of the screen automatically, depending on the content shown on the screen. In bright images, the backlight is increased, and in darker images, it is decreased. There is no real need to have a DCR of over 10,000:1 as you just wouldn't notice the difference in practice. The figures being quoted now are based on measurements of monitor states which would just never occur in real use. In fact modern DCR's of LED backlit screens assume the "black" state is in fact when the backlighting is turned off, in which case DCR would effectively be tending towards infinity:1. Just ignore DCR figures are they are not a reliable spec. In practice you would never achieve the numbers quoted. Far more important really is how effective the mechanism is and whether it is smooth and at what speed changes are made. Also keep in mind many people don't even like the technology at all!
     

  • Response time - Generally the lower the response time the better, but you need to understand the impact panel technology has on practical responsiveness. Also understand the difference between panels with and without Response Time Compensation (RTC) / Overdrive technologies as that can have a significant impact. Don't rely purely on a quoted response time figure on paper.
     

  • Colour gamut - don't assume that a higher colour gamut is better! The gamut represents the colour space that the backlighting unit of the monitor allows the screen to display. You need to understand that most normal content is based on a certain colour space (sRGB) and that there can be issues if you view this using a wide gamut screen. See here for more information.
     

  • Backlighting - LED backlighting is becoming increasingly common in modern screens with manufacturers making a lot of claims which aren't necessarily true. You need to understand what different backlighting will actually offer you. In reality, LED backlighting in mainstream screens is based on White-LED (W-LED) backlight units and only really offers benefits in terms of power consumption, screen thickness, and in environmental considerations. See this article for more information.

 


Q. Should I Be Worried About Ghosting?

A. Generally nowadays with all the 5ms, 4ms and 2ms response time rated models available, ghosting is just not an issue for the majority of users. Choosing a TFT can therefore often be based on design and looks, price and any extra features you might need. The fast response times of the panels used now are perfectly adequate to cut out pretty much all obvious ghosting and blurring, even in fast paced games. There are still some users who find the move from CRT screens to TFT a difficult change, but more and more users are switching over. With improving technologies being used, motion blur is becoming less of an issue.

Some time ago it is considered that a response time of 25ms or less should be fine for gaming in most cases. Panels with 16ms, 12ms and 8ms became common place and ghosting has become even less of a problem. The advent of overdrive (RTC technologies) saw a significant improvement in responsiveness in practice and quoted response time specs began to fall even more. This technology really helped improve response times with VA and IPS panels, finally making them feasible for gaming in many cases. Look out for response time specs quoted with a “G2G” (grey to grey) response time as that should indicate the use of overdrive technologies.

The arrival of other technologies designed to reduce perceived motion blur looks set to offer another marked improvement in the performance of LCD displays. These include the rarely used Black Frame Insertion (BFI) and Motion Picture Acceleration (MPA) technologies. However, more important in recent times has been the development of 120Hz LCD technologies. Nowadays screens supporting 120Hz input frequencies are becoming more and come common, and these can help reduce motion blur and ghosting and improve gaming performance considerably. They are also able to support higher frame rates than traditional 60Hz displays and are also capable of supporting 3D stereoscopic content through active shutter glasses. Do be careful of assuming that a screen advertised as supporting 3D is in fact able to support 120Hz though, as some 3D models do not support this and instead use passive methods to produce the 3D effect (see here for more info on 3D technologies)

Ghosting and motion blur perception may also depend on how susceptible you are as a user, as one person may see no ghosting, another may see lots on the same panel. The best bet is to try and see a TFT in action in a shop and see for yourself, if that’s not possible you will have to settle for the opinions of other users and take the plunge! Also be careful to get an idea of real life performance in practice, and don’t just rely on quoted specs. While they are often a good rough guide to the gaming performance, they are not always reliable.

Have a read here about response times if you are unsure about what specs mean or want more information. Generally modern TN Film panels will offer the fastest response times, and often also support 120Hz input frequencies for 3D support / extended frame rates. Look out for models with a quoted “G2G” response time indicating they also use overdrive which can really help in practice. Modern IPS panels can also be very fast where overdrive is applied well, so again look for “G2G” figures. Other technologies like PVA and MVA are unfortunately quite slow in practice by modern standards, even where overdrive is used. Check reviews to be sure of an individual screens performance wherever possible.

 


Q. Which Video Interface Connection Should I Use?

A. As a rule of thumb, it would normally be best to use the digital video connection end to end to connect your device to your monitor. For a PC, this would generally be DVI which offers a pure digital end to end connection between the graphics card and the monitor. D-sub/VGA on the other hand is often available as well, but has to convert the signal to analogue. In theory, digital connections should therefore offer a superior picture quality and a sharper image. In practice, this can depend on the model in question. There are a number of sharpening algorithms utilised for modern VGA interfaces which vary in the quality of the analogue/digital conversion. Some modern screens have such good analogue connections that it is very hard, or even impossible, to tell the difference between VGA and DVI. If you can use DVI, then you should, since it will offer the sharpest image available for the screen. If you are limited to VGA only, I'd suggest finding some user opinions or reviews about the picture quality (PQ) using this interface.

HDMI and DisplayPort are also common digital connections now being offer, but unlike DVI are also capable of carrying audio as well as video. The PQ should not be any different between DVI and HDMI/DisplayPort in theory as long as no additional video “enhancements” are applied when using one over the other.

Another thing to keep in mind is the maximum resolution supported from different connections and the native resolution of the screen you are using. For instance, a screen with a 2560 x 1440 or 2560 x 1600 resolution would require a Dual-link DVI (dual link is still a single connection, just with a higher bandwidth supported) or DisplayPort to operate at full resolution. HDMI and D-sub do not have the required bandwidth to support that full resolution.

 


Q.
Should I Worry About 6-bit vs. 8-bit vs. 10-bit Panels?

A. There is a lot of talk about colour depth on TFT screens, now more than ever with the emergence of 6-bit IPS and VA panels. At one time TN Film was the main 6-bit technology but today that is no longer the case. It's important to put this into perspective though, and not jump on the bandwagon of 8-bit being much, much better than 6-bit. Or even 10-bit being much better than 8-bit.

An 8-bit display would offer a colour palette of 16.7 million colours. They offer a 'true' colour palette, and are generally the choice of manufacturers for colour critical displays over 6-bit panels. On the other hand modern 6-bit screens use a range of Frame Rate Control (FRC) technologies to extend the colour palette from 262,144 colours to around 16.7m. In fact on many modern panels these FRC are very good and in practice you’d be hard pressed to spot any real difference between a 6-bit + FRC display and a true 8-bit display. Colour range is good, screens show no obvious gradation of colours, and they show no FRC artefacts or glitches in normal everyday use. Most average users would never notice the difference and so it is more important to think about the panel technology and your individual uses than get bogged down worrying about 6-bit vs. 8-bit arguments.

Manufacturers use 6-bit panels (+FRC) to help keep costs lower. As a result, a modern range of IPS and VA panels is also now produced which use 6-bit colour depth (+FRC) instead of true 8-bit colour depths. At the other end of the scale there are also some panels which can offer support of 10-bit colour depth. Again these come in two flavours, being either a true 10-bit panel (very rare and expensive) offering 1.07 billion colours or an 8-bit panel with an additional FRC stage added (1.07 billion colours produced through FRC). The 8-bit +FRC panels are of course more common and will often be used to offer “10-bit” support in desktop displays. With 10-bit colour though there is also an additional consideration which is whether you would ever even be able to use this in your work. You can also only make use of this 10-bit support if you have a full end-to-end 10-bit workflow, including a supporting software, graphics card and operating system which is still very rare and expensive for most users.


Note: Colour depth in this regard should not be confused with colour gamut

 


Q. What Does a Monitors Colour Gamut Mean?


A. Colour gamut or colour space refers to the range of colours which the screen is capable of showing, in relation to a reference colour space. The human eye can see a certain range of colours which is represented by a CIE Diagram. This shows the full range in reds, greens and blues which the eye can see. Within that massive range there are various reference colour spaces, the most common of these being the sRGB space. There are also other reference colour spaces such as the NTSC and Adobe RGB which are often used in specifications nowadays and may be used in certain workflows. These are larger colour spaces than sRGB, so manufacturers needed a way to quantify the changes they had made.

The colour space / gamut capability of a monitor is not determined by the panel technology, but rather by the backlight technology being used. Traditional screens used standard CCFL backlighting which (for simplicity of comparison here) offered a colour space covering the sRGB space almost exactly, which equates to about 72% of the now popular NTSC reference space. With backlighting technology changes and improvements, some screens then started to use WCG-CCFL (Wide Colour Gamut CCFL) backlighting which can offer an extended gamut covering commonly 92% - 102% of the NTSC reference space. Other backlighting technologies like W-LED (White LED) are also becoming very common, and at the moment cover the sRGB space (~68 – 72% NTSC). Some other LED backlights using RGB LED can cover >100% of the NTSC space as well but are prohibitively expensive and rarely used.

While a larger colour space might sound like a good idea, it's not always for everyone. You need to keep in mind what content you will be viewing on the screen, and what colour space that content is based on. Since sRGB is very common and the standard for many things like Windows and the internet, viewing sRGB content on an extended gamut screen can cause oversaturation of colours and an unrealistic 'stretching' of the colours. Reds and greens in particular can appear quite 'neon' and some users do not like this. The smaller colour space of the content is, as a very crude description, 'stretched' over the larger colour space of the monitor. On the other hand, some applications are colour space aware (e.g. Adobe Photoshop) and so if you are working with extended gamut content, you will prefer an extended gamut screen. I'd certainly recommend reading more into this as it is only a brief summary here. Where a screen has an extended gamut, they sometimes provide an sRGB emulation mode which work to varying degrees. Handy if you might need to use it, but make sure the screen offers a decent performance when in this mode and that it works. At the end of the day, the choice of monitor might very well depend on the colour space you want to work with. For most average users a standard CCFL or W-LED backlit display with a standard sRGB gamut would probably be preferred.
 



Q. What's The Best Way To Clean a TFT Screen?

A. The simplest and cheapest way to clean a TFT screen is with a slightly damp cloth; wipe off the left behind water with a towel or similar then smooth/dry completely with a yellow polishing cloth. Be careful not to use products such as toilet paper and kitchen roll as they contain lint and can leave scratches on your beloved screen! Cleaning solution from opticians and lint free clothes for lens cleaning are also very good.

For the perfectionist, there are also some very nice microfiber solutions available such as the ‘Cloth Addiction’ range.
 


Q. What's The Situation With Dead Pixels?

A. Unfortunately dead pixels can be an issue on TFT screens as they are often developed during the manufacturing stage. For retail costs to be kept low the companies cannot afford to make all screens defect-free and check for dead pixels all the time. Pixels can be described in the following ways:

  • Fully dead - stuck on black of white

  • Dead Sub Pixel - Stuck on Red / Green / Blue permanently

  • Lazy - stuck on a colour, but sometimes can change. If the pixels are only lazy, there may be hope of reviving them. If they are fully dead, they will stay that way.


Dead pixels very rarely develop during use, unless you have a habit of poking the screen. If you are careful with the screen, hopefully you shouldn't develop any further pixel problems.

To test for dead pixels, there is "Dead Pixel Buddy" program available. You can manually cycle through different full screen colours (black/white/red/green/blue) to check for dead or lazy pixels or rapidly cycle through all of the colours automatically to try and coax lazy sub-pixels back to life. Leave it running for half an hour, if you're lucky it can work!

If you want to ensure that you receive a pixel perfect screen (and who wouldn't at the kind of prices you are paying for the TFT!?!) then you can often pay for pixel checks from some online retailers. Beware though! Never buy a TFT from retailers who offer the pixel check without having the check done as you can be sure the screens they find to be non-perfect will be winging their way to the customers who don't have the check! The only other option to ensure you get a pixel perfect screen is to check out the panel in a shop in person, then you can see for yourself.....

If you find you have a dead pixel there is not a lot you can do unfortunately. If you have a certain number of dead pixels (usually at least 3 or a certain number centrally on the panel) then the manufacturer will replace the TFT for you, but the number of dead pixels needed before this happens varies between each manufacturer, so check with them before you order if you're concerned.

Some lazy pixels can be bought back to life occasionally. Playing some fast paced games for a while, and massaging / flicking the pixel area with a lint free cloth can sometimes help revive the lazy pixel, but not in all cases.

If you still have a dead pixel problem, can't bring it back to life and can't RMA it under warranty then you can sometimes return it to the stockist if you purchased it online. If you bought online you can take advantage of the "Distance Selling Act" which entitles you to return any item within 7 days as you were not present at the time of purchase. If you are not happy with your TFT you can return it at your cost of postage and often claim a refund or exchange. However, be aware that a lot of places will try and charge you restocking fees and they will almost certainly specify the goods must be packaged and in the same condition as when you received it, so be careful to package it back up nicely. Legally, if the stocker accepts the TFT back as a return governed by the Distance Selling Act, then they are NOT allowed to charge you a restocking fee as covered in the Government Regulations. This selling act is not widely advertised by retailers, but does exist if you really need to use it. You should only have to pay for postage to send it back to them.

 


Q. So Which Is The Best TFT To Get?

A. This question pops up ALL the time! It really depends on what you want the TFT for, how much you want to pay etc. Performance varies with different panel technologies and with different specs. Check out the TFT Selector Tool which will hopefully help you decide on the screen which suits your needs and is regularly updated. You also need to base your decision on the looks of the TFT, any extra functions which you might find useful, and the price.