Monitors for quality imaging work

bron: www.imagescience.com.au

Buying a monitor for imaging work generally represents a significant investment. But it's an investment definitely worth making if you care about image quality. Of course, like all investments, it's best made with the best information and unfortunately as ever there's more misinformation than information out there.

First - what are we ultimately looking for in a high quality monitor as image makers? Primarily we are looking for
accuracy - and specifically accuracy and control that allows the monitor to accurately simulate our final output medium (very rarely the monitor we are actually working on). 99 times out of 100, this means simulating the final print as accurately as possible. Accuracy is an entirely different thing to 'pleasing'. It is easy to make a monitor appeal to the human eye on the face of it. Much harder to make one that supports critical viewing of colour - and thus properly supports the decision making process when making images. It's much the same as with TV shopping - go to a well set up TV store and all the TVs will have Pixar animated movies playing on them - bright, saturated and impossibly shiny, they make the TVs look great - but tell you absolutely nothing about the general ability of the TV to display colour correctly.

The fact is, general purpose monitors are easy to make and are sold in such numbers that their incredibly cheap pricing makes them very tempting - why pay $2000 or even $4000 for a super duper 24 inch screen when Dell make one for $400? And on the face of it, the Dell monitor seems to have good specifications - often specifications that are on the face of it on par with the NEC or Eizo models. And even when you look at the screen live, it looks good - high contrast, lots of saturated colour, sharp enough, that sort of thing. The natural reaction is to conclude you're not missing much, that there really isn't THAT much difference between a general desktop monitor and a proper imaging monitor. Wrong. Wrong wrong wrong!

Put the Dell next to a monitor designed specifically for imaging work, and display some real images on them, and suddenly it becomes clear that specifications on paper tell very little about the real performance of a monitor. A long list of features with whizz bang names (Ultrasharp TrueColour Overdrive etc etc) - does not make for accurate, pleasing, and natural display of images. The Dell is simply lying to you about colour - typically out of the box they are very bright, very saturated, and very contrasty. And nothing like paper. And they don't have controls to fix this problem - sure, some of them pretend to have controls but when you actually use these controls (say to turn down contrast, or de-saturate the image) they actually do more harm than good - by attempting to calibrate these sorts of screens, the net result is a screen with all sorts of post calibration artifacts - the most obvious of which is
banding in gradients.

As image makers we need good monitors to help us make better images - a good monitor, that is a good predictor of our final input, makes for better decision making. On really excellent monitors, it's like you are working on the print itself - directly, almost as if the monitor doesn't exist. In a way it takes us back to the darkroom, or to the actual process of working directly with tone on paper.

Panel Types


One of the key traditional decision to make when choosing a high class monitor is to choose between a (S)PVA panel and an (S)IPS panel. But in the modern day, it shouldn't be the primary factor when choosing a monitor. Gone are the days when one technology is clearly better than the other - now excellent panels of both types are available and it is in fact the surrounding electronics that really counts (see the next section). That said, it is still worth discussing the inherent strengths and weaknesses of the two most popular panel types.

Traditionally, IPS panels have offered better colour reproduction than PVA panels. That said, PVA panels have come a very long way in recent years and the difference is certainly not what it once was. Indeed, we have two screens in the office here, one SIPS and one SPVA, and I struggle to see any real practical difference in real world usage when sitting in front of either screen and editing images. As long as the panel in question is an excellent panel of its type, there is not a huge lot between them when sitting in front of them.

There are some differences. For example, PVA panels are generally much brighter than IPS panels. This means they tend to be a little less even across their field, and in most cases you turn them down to about 10% of their max brightness when calibrating them. The extra brightness can be great for working with video, especially during the day. PVA panels tend to have more variance across their field than IPS Panels. Most people don't find the slight shift in brightness across the field to be an issue of actual practical importance. If you're really concerned about having a perfectly even field, select a higher end model with a uniformity system (all NEC monitors have a uniformity system, Eizo have this system in their Flexscan Premium and ColorEdge range, but not the Flexscan range). A uniformity system guarantees the display field will be even in both brightness and colour terms within tight tolerances.

IPS panels tend to have lower native contrast than PVA panels. See below for more about contrast, but this is actually an advantage of IPS panels - lower contrast is in fact better for simulating paper. Another noticeable difference is that if you're sufficiently off angle (i.e. looking at your screen from the side), then the IPS panel continues to display colour accurately noticeably more than the PVA panel. Directly in front, they are uncannily similar, but from the side, this extra colour accuracy may prove to be quite important in certain contexts - such as when showing work to clients. However, IPS screens, off angle, tend to have a slightly blue and weak quality to their blacks, while PVA screens have deep, inky blacks on any angle.

If you're a graphic designer, and want the smoothest possible gradients, an IPS panel will help there as well.

PVA models have faster gray to gray refresh times - meaning they're better for video work. Irrelevant for photography, but if you edit or watch videos regularly, a PVA is probably a better choice.

To repeat - for general imaging use, from front on or within 40 degrees or so, there is now not a lot of difference and both PVA and IPS panels offer excellent, accurate, and smooth colour once calibrated, if the panels themselves are high quality (like all from NEC and Eizo are), and if they are surrounded with excellent stability and calibration electronics (and again, Eizo and NEC lead the way here).

What to look for? Why is (feature) important?


In order of most important to least, for imaging work:

High Bit Depth Panel Electronics - This is the most important thing to look for. In short, this means the electronics surrounding the panel can control the panel and adjust its picture (i.e. calibrate the panel) with very high quality. Cheap monitors are usually 6 bit panels - and this is disasterous for colour (for example the 20" iMac uses one of these panels and is, quite frankly, about as bad as monitors get). Typical mid priced panels are 8 bits, which are fine for day to day use but once calibrated these usually display significant problems such as banding in greyscales (this includes pretty much all Dell and Apple monitors, and most general consumer brands like Samsung/Viewsonic etc). High quality monitors (NEC, Eizo) have 10, 12, 14 or 16 bit panels.

Remember, the goal is to make our monitor the best simulator for our final output as we possibly can - and this means adjusting the entire colour response of the monitor. Typically, white point colour and brightness, RGB gamma (or tonal response from dark to light), and black point are adjusted. When these adjustments are made on standard monitors (6 or 8 bit), they quickly induce artefacts as only a maximum of 256 tonal levels are available to begin with, and all adjustments during calibration will reduce the number of levels. Insufficient levels means visible banding. With higher bit depths, more levels are available, and even post adjustment, plenty of levels are still available - this means no banding and no tonal compression in shadows and highlights, as a result of adjusting the monitors display closer to paper. And this is fundamental to accurate image display. High bit depth makes a panel flexible and accurate. And high bit depth panels simply aren't available in consumer brands.

High bit depth in the panel electronics is the primary thing to look for. But you must remember that this is only relevant to the calibration stage of monitor colour control - that is, these high bit depth chips are used when physically adjusting the monitor, but not necessarily during the second stage - profiling the monitor. See point three below.

General Accuracy Of Display - There's no real specification that tells you this, but there are certification tools that can measure this. NEC and Eizo monitors - and particularly the high end monitors in the Eizo CG and NEC SpectraView lines - leave the factory calibrated to a standard that is unheard of in the consumer market. This means when you first set them up, even before calibration, they are fundamentally far more accurate than anything you're likely to have seen before. NEC and Eizo monitors are the main two brands that can pass the very stringent certification tests from professional standards bodies like UGRA/FOGRA/ISO etc. While passing certification is not necessarily something required in everybody's workflow, the ability to hit these accuracy targets and hold them is precisely what makes these monitors so good at their primary function - simulating the final printed output.

Extensive Calibration Controls - Good monitors must have extensive controls for adjusting their picture to appropriate targets. Most importantly is a brightness control that can drop a monitor's display down to a reasonable level to simulate paper - this is where many consumer monitors fail absolutely. For example, the current iMac 24" screen has a minimum brightness of 250 cd/m2 (and out of the box they are a truly retina destroying 400 cd/m2!). This is ridiculous and a huge fundamental failing for image makers - an approximate recommendation for most working environments for print production work, would be brightness of around 90 to 110 cd/m2. This means the iMac is, at best, two and a half times brighter than it should be to simulate paper - and there's no physical control to adjust this. With a 24" iMac you will forever find your prints seem darker than your screen - and there is nothing you can do to fix this (except buy a much better external screen - thankfully the iMac has video output port!).

In addition to a brightness control with sufficient range (ideally anything between about 60 to 200+ candellas should be achievable), monitors must have excellent controls to reach specific gamma targets (i.e. have an appropriate tonal progression from dark to light) and specific colour targets (e.g. white points in the range of about 4500 to 7000 Kelvin).

Many cheaper monitors seem to have these controls - but remember the issues above with low bit depth panels. They are doing their adjustments with low bit depth maths - and this means using these controls will induce visible artifacts (banding, tonal compression etc). On good monitors, all of these physical calibration adjustments are done in the higher bit depth chips and the result is no artifacts once you have physically adjusted your monitor.

Direct hardware calibration (should really be known as direct hardware profiling!) - Read more about the different types of calibration here. This is a very useful feature to have - it means in the second stage of monitor colour control - i.e. profiling - all the adjustments are made directly into the high bit depth LUT tables in the monitor itself (basically these high quality monitors include a very high quality video card in the back of them!). In cheaper monitors, these adjustments are made to the video card's 8 bit LUT instead - and again, this typically induces artifacts. Above and beyond that, it is also usually the fastest and easiest way to calibrate & profile a monitor - you don't have to touch the monitor's controls as it's all taken care of for you - just define your settings and let the system do the work for you! You can go make a cup of tea while your monitor adjusts itself to perfect colour!

High Bit Depth Input - Some very new monitors (Eizo CG243W and NEC PA Series) can accept a 10 bit input signal from high end video cards (more details here). The result of 10 bit input is that the incoming signal is much higher quality - having over 100 discrete signal levels instead of the normal 256 signals with 8 bit input. The net result is smoother, more accurate colour and a more robust system that can stand greater manipulation (for example, calibrating to printer gamuts in the monitor hardware itself and other exotic things).

True Contrast Control - LCD monitors have inherently high contrast. This makes them look appealing initially, and is great for movies and games - but it also makes them struggle with simulating paper, which is inherently a low contrast medium. Print contrast varies depending on the paper and inks used, but a rule of thumb is about 200:1 is an appropriate contrast level for simulating paper. High end LCDs (Eizo CG and NEC SpectraView) offer control over contrast - that is, these monitors can reduce the native contrast of the panel to a level much more like that of paper. They do this by letting you set specific target points for the brightness of both the deepest black (black point) and the brightest white (white point). The contrast ratio of a monitor is calculated by dividing the white point by the blackpoint - for example, a white point of 100 candellas and a black point of 0.5 candellas means 100/0.5 or 200:1 contrast.

Simulating paper contrast is a very important part of print matching. An image on a screen with 1000:1 contrast will always look far more contrasty that the final print - and this means your editing decisions will be based on this incorrect display. I have previously written about this here.

Uniformity Systems - Because of the way LCD monitors work, basically a bunch of filters in front of fluorescent tubes or LED back lights, they are inherently uneven across their field - in both brightness and colour. On large, low quality monitors especially, there can be HUGE differences across the panel. Open a grey scale image in Photoshop and then open a second copy of it (Window->Arrange->New Window For....[filename]). Move the two windows around your screen (e.g. to opposite corners) and compare them - you will typically see significant variance in brightness and quite possibly in colour as well (for example, Apple Cinema displays are notorious for colour casts in the corners - I recently saw a 23" cinema display that has at least two stops brighter in the corner than the center, and a good 10% more magenta as well - just awful!).

If you tend to retouch images side by side, this can be a significant problem. If the variance is only minor and around the edges, it may not be a big practical problem, but if like most people you display the image your working on full screen across your entire display, there may be as much as 30% variance in brightness across the image - meaning for example, the left hand side of your image will look artificially brighter than the right purely because of a uniformity issue. If you edit your image based on this, you will simply be damaging your image in an effort to make up for the deficiencies of your display.

Almost all NEC monitors, and Eizo CG and Flexscan Premium (but not Flexscan Standard) monitors, have uniformity systems. Essentially, this means before the monitor leaves the factory, it is measured across the entire field in 25+ separate zones, and then each zone is individually tuned to make sure the display is even across the entire field, within reasonable tolerances. The NEC SpectraView and Eizo CG tolerances are particularly tight and the screens are essentially perfectly even across their entire field.

Note this is a once off factory calibration - once several years have passed (5+), the panel will realistically begin to show some visible unevenness again. But because the original tolerances are so tight, it will be some significant time before the level of unevenness gets back to a point where it poses a practical problem (and in say 10 years, we imagine all screens will likely have uniformity systems!).

Matte, NOT GLOSS! Good quality LCD screens must have a matte surface, not a shiny, reflective gloss coating. Gloss is bad in every way - it increases contrast (which we don't want, see above) - and it dramatically increases the reflectively characteristics of the screen, which is again very bad. High quality screens all have very matte surfaces that minimise reflections and allow for a very pleasing, natural display. Very high quality screens have lens grade coatings on them for extremely high quality display, and this gives images on these screens a wonderfully natural, three dimensional quality.

Wide Gamut Support - Gamut is the total range of colours a screen can display. Standard gamut is roughly the size of the sRGB colourspace - about 76% of the AdobeRGB colourspace, which is pretty much the standard colour space recommended by most professional bodies in Australia for RGB work. Standard gamut, in more human terms, is roughly the amount of colour a typical television set can display.

New and high quality monitors are beginning to support a wider gamut than traditional monitors - up to 102% of AdobeRGB colours (or even more) are displayable on these screens. Meaning they can be used for high saturation work with greater accuracy. While this is handy, truth be told the vast bulk of work can be done on standard gamut monitors without trouble But as cameras and printers get better, wide gamut support is becoming increasingly important.

Ease of use - Good on screen controls are very important (on monitors without direct hardware calibration!). Most monitors have pretty awful menu systems. The NEC monitors in particular have excellent, easy to use controls.

Backup, Warranty and Support - Consumer monitors typically have 12 months warranties and quite frankly they seem to be made in such a way as they drop like flies after those 12 months are up.

NEC have a 15 day Zero Dead Pixel and DOA period across their entire range - so if anything at all goes wrong during the first 15 days you are completely covered and get a replacement screen, no fuss! Then you have three years of full parts and labour warranty support. This is excellent and we think overall it is the best warranty in the business.

Eizo have a 5 year warranty - seemingly unmatched in length in the industry. The devil is in the fine print however - their zero dead pixel support is unfortunately only on the Eizo CG and SX lines (for 14 days). Also, the 5 year warranty is limited in how you can use the monitor (brightness, etc) and the coverage on major parts like the backlight is limited to one or three years. Their warranty is therefore a little over-stated, but overall a close second to the NEC warranty. Dead pixels are very very rare on Eizo screens, so mostly it is a total non-issue.

Eizo and NEC both have excellent, knowledgeable second line support for more complex issues (first line support is through us, of course, as we know a LOT about these screens through extensive professional use).

A note on 'Zero Dead Pixel' warranties - While many other manufacturer's claim to have this, its worth reading the fine print very carefully. Typically the coverage is only for the first few days (which is reasonable as dead pixels are a manufacturing fault and do not appear during a monitor's life). But there are often also restrictions on the coverage if the pixel is near the bezel edge, for instance. Some restrict the coverage to a very small part of the screen in the dead center - not very useful on a massive 24" monitor! So read the fine print on this if it is of big concern to you - the reality is that while it can be annoying, a single dead pixel is a tiny, tiny fault in an otherwise perfect screen, and it really causes no more practical harm than a speck of dust on the screen.

Screen Size and Shape, Pivot Support - This comes down to budget and desk space - bigger is always better! That said we thoroughly recommend you buy a high quality small screen rather than a low quality big screen if the budget is limited. The best is of course a big, high quality screen, with 24 to 30 inches being just marvelous for editing big images, seeing double page spreads, etc, with room for palettes. But plenty of professionals do just fine working with high quality 19 or 20" screens.

Widescreen is our personal favourite but it's really personal preference. It has to be said that increasingly traditional format screens seem to be disappearing pretty rapidly, and user interface design is increasingly taking advantage of the extra horizontal space.

An alternative is a second cheap screen as a palette monitor and this can be a very cost effective way of increasing screen real estate - and the quality of the seond panel is almost irrelevant as it is just for palettes. Be aware under Windows it is likely you will not be able to calibrate the second screen without using two video cards (see here).

Pivot support is very useful if you do a lot of portrait work - and most NEC and Eizo monitors support this (you will also need a video card that supports pivoting, but most do).

Specific Recommendations


The Best of the Best - Eizo CG and NEC PA Monitors. These two lines of monitors represent the best monitor technologies available on the market today. These are serious imaging devices for serious image makers, in every way. Not only do they offer the very best performance, but thanks to direct hardware calibration they also make the advanced features easy to use. This allows you to stop focusing on technical issues, to largely forget about colour management, and to get back to the important stuff - actually working on your images.

While you will pay a significant premium, you will enjoy the benefits of the screens long, long after the sticker shock has faded.

Modern image makers spend more time, and do more of their creative work, in front of their monitor than anywhere else. In my opinion, a high quality monitor is worth its weight in gold and goes hand in hand with producing very high quality work - because they offer tremendous control. It's all about good tools supporting good craft and these monitors are the very best tools you can get.

Best general purpose options for professionals (budget $2000 to $4000): We think the best value right now are the NEC PA series monitors (with SpectraView 2 of course) - their combination of quality and price point is really unmatched at the moment. These really look set to become the industry standard colour accurate monitors over the next year or two.

For those on a tighter budget (around $1200): We suggest the NEC P221W (with Spectraview 2 of course) - there's not much out there to touch this screen at the price it is at.

Those on a very tight budget: Honestly, wait a while and save up and go for the P221W above, otherwise the Eizo S1921 or the NEC LCD1990SX are both excellent small monitors - far superior for imaging work than anything Dell/Apple/Viewsonic etc etc have ever produced.

Add a $100 15" cheap panel from Officeworks for palettes and you still have plenty of screen real estate to work with AND you can keep all your colour accurate work in the better quality screen. Very effective for less than $1000.

For those that can't afford an Eizo/NEC: Save up a bit longer. Honestly - this is the best advice we can give you. It's not worth spending $500 on a Dell now only to find that it's $500 you should have put to an Eizo or NEC monitor. If you love imaging, and/or make your living from it, a good monitor is essential. (And a good monitor calibrator). These two tools will be at the base of everything you do in digital imaging. Make sure you have a solid foundation for your work. Even if you have to start with a small screen, remember that people made do with 19" screens for years and years before all these big screens came along. You can always upgrade later as prices come down, but you can't get the time and money you wasted on a crappy monitor back. Life is simply too short to look at bad colour!