How to calibrate your monitor

The poor old monitor. In development terms CPUs and GPUs leave it choking in their digital dust. 4K screen res may be the next big thing, but try extending the pixel density of an HTC One’s screen to cover a 27-inch monitor and you’d get the equivalent of 11K. To put it another way, that’s 68.4 megapixels and a gaming experience measured in frames per week, but we’ll gloss over that.

Anyway, seeing as you’re likely to be stuck with your dear old display for some time yet, it makes sense to get the best out of it. Correct positioning is a good start, and you’ll probably want to fiddle with the brightness and contrast controls to strike a balance between good visibility and a headache, but the fun really begins when you want to ensure colours are accurately displayed. How are you supposed to tell how closely your monitor’s idea of red or green matches a predefined benchmark such as the sRGB colour space?

Now hold up. Before you skip straight to the gaming reviews, assuming this kind of anal pixel play is the preserve of Photoshop junkies, consider this: a monitor is your primary means of interacting with your PC. OK, a mouse and keyboard help, but they’re not much help if you can’t see anything. A well calibrated monitor is certainly good news for photo-editing, but sorting your screen is also going to give you the best possible gaming and movie experience. Fed up with being at the mercy of shadow-bound enemies everyone else seems to see? Calibrate. Confused why every other scene in your Blu-ray of The Matrix looks like it’s been filmed through the camera man’s Ray-Bans, or why Shrek’s skin tone is making him look like the illegitimate lovechild of Cookie Monster and Smurfette? Yup, you know what to do. Book an eye test.

So don’t get too hung up on trying to clock that extra 100MHz out of your CPU, as let’s face it, you’ll never notice the difference. Try showing your monitor some love for a change instead.

Why calibrate?

You’d have thought all monitors would come pre-calibrated to display at their best. After all, this isn’t just a telly, it’s a monitor; it’s supposed to give an unbiased, completely accurate view of what’s coming out of your graphics card. Trouble is, as you’ll know from a trip past JB’s storefront, LCD makers have varying ideas of what constitutes optimum image quality. That’s fine if all you want to do is churn your way through Keeping Up with the Kardashians (you monster), but those of us with sophisticated viewing requirements demand more from our monitors.

Monitor calibration ensures the colour output from your monitor matches a predefined standard, rather than whatever it happens to display after rolling off the production line. The calibration process doesn’t alter anything about the monitor itself, apart from adjusting any internal settings like brightness or contrast. Instead, calibration detects the colours emitted by your screen and creates a bespoke software profile that tells Windows and your graphics drivers how to compensate for any colour discrepancies. Now your graphics card can distort its output so what you end up seeing on your monitor conforms to a preset colour benchmark such as the sRGB or Adobe RGB colour space.

All this faffing is usually left to digital imaging fanatics who need the utmost consistency for image editing and printing, but we gaming and video enthusiasts can also reap the rewards of a modified monitor. After all, what’s the point in setting up the perfect mouse DPI, fine tuning custom macros and tweaking graphics quality for maximum frame rates when bad contrast or gamma settings could give you all the vision of gaming behind a welding mask? Likewise, a large part of a game like Fez’s visual appeal is its carefully chosen colour palette, so it makes sense to banish your monitor’s colour cockups and view these digital landscapes as their designers intended.

Pre-calibration checks

Ensuring your screen is up to scratch is easier than you may think. Sure, you can go mad and spend upwards of a grand on professional calibration hardware, but that would be insane when you could get so many more interesting gadgets for that price. No, it may surprise you, but it’ll cost naff-all to get the basics in order.

First, make sure your monitor is positioned correctly. Generally you want the top edge of the screen to be level with your sight line when looking dead ahead. Some TN-based panels may look a bit washed out positioned like this, in which case you should raise the screen until the upper and lower halves can be viewed as clearly as possible.

Ambient lighting also plays a major part on monitor visibility, so wherever possible, try to minimise on-screen reflections and perform any calibration tests in your typical viewing conditions.

At the risk of stating the obvious here, make sure your monitor is set to its native maximum resolution. Back in the day, your bulky old CRT monitor would look crisp at various resolutions, but setting an LCD to anything less than max res results in blurry antialiasing as the monitor struggles to expand the unexpectedly low pixel count coming from your graphics card to fill the available screen space.

Next, delve in to your monitor’s own display settings. Some will have more inbuilt options than others, but hunt around for a colour temperature control. This sets the tone – or warmth – of light emitted from each pixel, from a 2,500k temperature that roughly equates to the orangey light you’d expect from a traditional tungsten light bulb, up to the bluish 9,300K (or D93) temperature many monitors are preset to. This might look fresh and crisp in Word, but games and films will are best displayed at a more daylight-balanced colour temperature of 6,500K, or D65. Stepping down to this from 9300K is going to look as though the world has turned sepia for a bit, but give it a chance, as colours will be displayed more accurately.

We’re almost ready to calibrate, but if you’ve only just powered up your monitor, it’s best to let it ‘warm up’ for at least 20 minutes so the panel’s backlighting reaches optimal brightness and emits a consistent colour temperature.

Windows Calibration

Windows includes a calibration utility, but it’s well hidden. To find it, type calibrate into the Start search box in Windows 7, or the Charms search box in Windows 8, then select ‘Calibrate display color’.

The first thing you get to play with is the gamma setting, which is something you’ve probably seen mentioned on the display options in many a game. Gamma correction has the power to lift murky shadow areas and reveal any sneaky sods waiting to pounce, or alternatively restore highlight detail from an oversaturated sky. Defining gamma and gamma correction is rather tricky – so much so that you need to use words like ‘relative luminance’ and ‘nonlinear perceptual response’. What matters is that messing with gamma correction is similar to adjusting both brightness and contrast at once. Windows adopts the Three Bears approach to setting the right gamma correction, giving you examples of too much gamma, too little and just the right amount. All you need to do is tweak one slider to match the preferable mid-point.

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The Windows calibration tool is basic, but it does the job.

Next is the all-important brightness and contrast adjustment, again performed via your monitor’s controls and aided by downright dreary Windows images of a man in a white shirt shot against a contrasty background (Ballmer, some choice over the sample images please? Preferably between Zooey Deschanel and Mila Kunis, but we’ll take Clooney too in the name of gender balance). Anyway, daydreaming aside, the sample images you do get aren’t exactly ideal for the job at hand, so check out the next section to find out how to ensure you’ve nailed the correct brightness and contrast settings.

The process concludes with Windows having a go at helping you set the correct colour balance for your screen. You’re given three sliders to tune the red, green and blue colour channels, plus a simple greyscale chart to aid the process. It’s all easy enough, but not terribly accurate. You can offset any blatant colour casts, but if you want to do better, shelling out for calibration hardware is the only way to go.

And that’s it. In next to no time you’ve tuned out any potential image quality hiccups that could get in the way of your gaming, or have you seeing red when you needn’t. That’s not to say Windows is the last word in software calibration accuracy though, so if you fancy going the extra mile then you can set up your own calibration tests and still keep costs at diddly-squat.

DIY Calibration

One issue with calibrating your panel using Windows is that it relies on your monitor having on-board brightness or contrast controls. If yours doesn’t, then your graphics driver software will undoubtedly be able to adjust these settings itself, and usually do plenty more besides. For instance the Nvidia Control Panel includes an option called Digital Vibrance that’ll increase colour saturation in a more subtle fashion than a traditional saturation slider. This can make a game like Far Cry 3 look ultra-luscious, but remember that the effect is completely fake and isn’t really what monitor calibration is all about.

nvidia-control-panel-colour-settings

If all else fails, your graphics drivers should come to the rescue.

Returning to the task of tweaking brightness and contrast, you’ll still need some form of sample image to know how far to adjust things, and to be honest, shots of semi-naked celebs probably aren’t your best bet here. Instead, it’s time to turn to the (almost as enticing) greyscale chart. These visual benchmarks tend to be used for printer calibration, but they work just as well for setting up a monitor. A quick Google search should deliver the goods, but make sure you download a chart with at least 20 steps of grey ranging from pure white to pure black. The objective here is to get every stage on the scale to display clearly, from a crisp white to a deep, inky black. Pay close attention at these extremes, because a monitor with its brightness cranked to the max will often merge the lightest greys into white, and do the opposite when set too dimly. Most half-decent monitors should be able to display this many shades of grey separately, but if yours can’t then try to strike a balance between displaying as many light and dark shades as possible.

greyscale-chart-monitor-calibration

Remind you of Knight Rider, in black and white?

Now turn your attention to gamma correction. The freeware QuickGamma tool is worth a try, as it offers far clearer test patterns than Windows provides. You’ll be met with a headache-inducing chart of alternate fine light and dark grey lines, but sit back and squint so the lines appear as two solid columns. Ideally the halfway point on the scale, marked 2.2, should display the backing colour, and the two columns of alternating lines at the same shade of grey and your gamma will be bang on. If the shades blend further up or down the scale, use the plus and minus buttons on the right hand side to raise or lower the gamma correction so the test chart balances at 2.2.

There are options for adjusting gamma separately for the red, green and blue channels, which comes in handy for correcting any slight colour casts. Be warned though, as these separate tweaks can end up causing more problems than they solve. The danger is that you can easily lose track of what was a half decent colour balance and struggle to get things back to normal without just cancelling out of the whole adjustment.

quickgamma-tool

Stare at these patterns long enough and you’ll reach Nirvana.

Hardware calibration

No matter how seriously you take this software calibration malarkey, there’s always going to be a weak link in the process, and it isn’t the lack of sexy celeb shots in the Windows calibration utility. No, worryingly it’s the human eye that’s not to be trusted here. Even if you have perfect vision, the eye just isn’t an objective judge of colour balance or consistency. Take that classic shadow on a checkerboard optical illusion. Stick a Photoshop colour picker on both squares and it’s clear they’re exactly the same shade, but our pathetic noggins just won’t see it. To get around the problem and calibrate your screen properly, there really is no alternative but to splash out on a robotic eye. But fear not, as you can pick one up for under $200. It won’t look like a prop from The Terminator though. Pity.

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Squares A and B are the same colour. Still trust your eyes to calibrate?

The device in question is related to what car body repair shops use to match paint colours during a respray. This nifty little gadget is usually about the size of a mouse and only requires a USB connection. Simply hang it over the top of the screen so it rests in the middle where a monitor’s brightness tends to be at its best, then corresponding software flashes various different colours over a period of several minutes for the all-seeing eye to detect. This then feeds the colour data back to the software so it can create a custom Windows colour profile for your monitor. More advanced colorimeters can even read ambient light levels to tell you the optimal brightness for your viewing conditions.

Colorimeters aren’t the only hardware you can use for monitor calibration. Spectrophotometers look pretty much identical and do the same job, but they can also calibrate your printer because they’re capable of analysing both emitted light from monitors and light reflected off printed colour swatches. The only downside is price, as spectrophotometers usually cost considerably more than hardware dedicated solely to monitor calibration.

Once the calibration is done and Windows has the unique colour profile for your monitor, you’re almost home and dry. Remember that the brightness and colour reproduction of any monitor will fluctuate over time, so to keep everything consistent you should repeat the calibration process once every few months.

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To calibrate properly, one of these gizmos is a must.

Choosing the right calibration tool

Using Windows or other software calibration tools will certainly solve any glaring image quality issues, and will ensure you don’t miss anything while gaming. However, to be absolutely sure your monitor’s colour output is spot on, you’ll need to invest in some hardware.

Two brands have the colour calibration market pretty much sewn up: X-Rite Pantone and Datacolor. The former produces one of the most inexpensive colorimeters available, called the ColorMunki Smile. Don’t be put off by the silly name, as this effortlessly easy to use gadget will give almost as much calibration accuracy as devices costing several times its sub-$120 price tag.

colormunki-smile-monitor-calibration-tool

Calibration tools like these will help you get the best from your monitor.

Since the Smile is an entry-level device, you’ll need to wait a relatively sluggish five minutes for it to complete the colour calibration process, but when it finishes and saves the freshly tweaked colour settings to Windows, they’ll load automatically every time your system boots. The calibration software can also be installed on more than one machine, should you want to calibrate your other desktop computers or laptops.

The only downsides with the ColorMunki Smile are that it is unable to calibrate a multi-monitor setup, and it can’t measure ambient light to ensure that your monitor’s brightness is set appropriately. For that kind of control you’ll need to step up to a device such as Datacolor’s Spyder 4 Pro. At a cool $185 this is a more serious piece of kit, but it will help you get the very best from your monitor.

Of course you can spend even more, but then you’re into the realm of calibration kits designed to scan not only your monitor, but also colour match it with print material. Unless you’re a die-hard photo editing and printing enthusiast, this kind of money would be far better spent on a quality monitor that’s likely to come calibrated fairly accurately right out of the box.

How calibration tools actually work

To understand colour calibration, we need to take a trip back to a time when, ironically, the world was in black and white – 1931. This was when the first mathematical chart defining the range of colours visible to the human eye was created, dubbed the CIE 1931 Colour Space. What’s nice about a chart is that you can define coordinates for each colour, which is rather handy for this calibration business.

cie-1931-colour-space-chart

Ideally, all monitors would be capable of displaying the same colour spectrum our eyes can detect, but the cost of such a display would make a Titan SLI setup seem cheap. To create a more realistic standard, less extensive colour spaces such as sRGB and Adobe RGB were devised. The vast majority of current monitors should display the sRGB colour spectrum, with pro-spec IPS monitors covering the extra colours incorporated by the Adobe RGB colour space.

Calibration software displays a range of colours within this spectrum. The colorimeter then detects each colour displayed by the monitor, references it with the colour’s coordinates in the sRGB chart and works out the correction required to get the monitor’s interpretation to sync with its location in the sRGB colour space. The software then creates a colour profile incorporating all these correction values into one table. This is loaded into the graphics driver so your graphics card can modify its colour output by the amounts specified in the colour calibration profile.

Different display technologies

Just as correcting the grammatical errors in Fifty Shades of Grey isn’t going to make it a literary masterpiece, even the fanciest calibration kit won’t help a crummy monitor display… well… extra shades of grey.

Thankfully a large-screen monitor with decent image quality no longer costs the earth, as the smartphone and tablet revolution has done wonders for raising awareness of IPS (in-plane switching) LCD tech and its superior viewing angles and colour consistency. Desktop monitor manufactures are now keener than ever to flaunt IPS at lower prices, so you too can enjoy the significant image quality boost over an old monitor using a TN (twisted nematic) LCD.

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Of course aside from their comparatively high price, IPS screens used to fall short of TN-based panels when it comes to response time. Whilst IPS still can’t match the 1 or 2ms figures boasted by the fastest TN screens, many can now reach the 6ms mark, which is fast enough to eliminate any noticeable image ghosting from even the most frantic gaming melees.

The fact remains that IPS screens are still pricier than their TN counterparts, but the difference is much smaller than it used to be. That’s meant that the third member of the LCD screen tech trio, VA (vertical alignment) is now becoming a relatively rare breed. Pity, considering VA-based monitors tend to give a good balance between colour accuracy, response time and cost.

Shop around and a 23-inch 1,920 x 1,080 IPS screen can be had for as little as $180. If you’re feeling flush, then there are plenty of bargain 27-inch 2,560 x 1,440 IPS displays to be had at right now as well. Take a look at this month’s labs test, where we look at the best ultra high resolutions screens currently available, and highlight the best ones to drop your cash on.

  • For instance the Nvidia Control Panel includes an option called Digital Vibrance that’ll increase colour saturation in a more subtle fashion than a traditional saturation slider. This can make a game like Far Cry 3 look ultra-luscious, but remember that the effect is completely fake and isn’t really what monitor calibration is all about.