Watch Out: Crazy Contrast Ratios

Can you still believe the tech specs on a monitor? If it's impossible to reach 10 000:1 or 8 000 000:1, what are manufacturers playing at by promising such contrast ratios?

Vincent Alzieu
Updated: March 1, 2010

What is a contrast ratio?

Contrast ratios are written as '1000:1', which means, for instance, that white areas of the screen are a thousand times brighter than black areas.

Sometimes, manufactures quote two different ratios on the same line, and you see things like ''Contrast: 10 000:1 (typical: 1 000:1)'' Contrary to expectations, it's this second figure, in brackets, which is more important. It's the 'typical' contrast measured using the screen't default settings, while the former is usually for 'dynamic' contrast. Dynamic contrast is measured using an automatic image correction system on the screen, which promotes the best possible contrast, but at the expense of producing a neutral image overall. Even using these settings, though, we've never been able to reproduce the results claimed by manufacturers--and I mean never! No manufacturer has ever agreed to tell us anything about the test procedures they use either.

But it's the dynamic figure that usually finds its way into stores, onto websites and minimum specs from big buyers--and that's the thing we have a problem with. Here at DigitalVersus we're declaring war on dynamic contrast.

More Detail?

To calculate a contrast ratio, we use a colorimeter to examine how bright a white square is in the middle of larger black square. The ideal result is for the black area to produce no light, but that's never the case: some always seeps through. A very good monitor has blacks with less than 0.1 cd/m², but above 0.3 cd/m² they begin to look washed out.

Having a higher contrast ratio allows monitors to produce the darkest possible blacks and produce a more accurate depiction of darker colours. Screens with low contrast ratios often blur darker shades of grey and black into a single colour.

Remember CRT monitors?

There are plenty of people who regret the 'good old days,' but does that include CRT monitors? We went back to take a look at some of our old results, and found that back then, contrast ratios weren't real a big selling point.

They were rarely, if ever, even quoted, so all that we have is our own lab results. Back then, tube-based screens (CRTs), managed to produce whites of 100 cd/m², with 0.3 cd/m² blacks. That's a final contrast ratio of 333:1, or between a half and a third of what today's LCDs can manage.

Some monitor manufacturers are worse than Bernard Madoff: they promise you millions but you end up with nothing. How have we come to have such a massive gulf between fact and fiction? How can the specs be so wrong? And is actual dishonesty involved, or are consumers also guilty of naively believing the marketing promises?

The saddest part of this story is that everybody realises the whole situation is ridiculous, but rather than applying the brakes and calming things down, the manufactures are all putting their foot to the floor and racing to outpace the opposition. All of them are guilty of putting out bogus documentation with unreal stats, but everybody claims it's somebody else's fault!

Their claims vs our results

We've found screens with wild claims about their contrast ratio from every one of the monitor manufacturers whose products we've tested, with just three exceptions: Apple, LaCie and Eizo. And we can put the last of those three to one side for the time being, because Eizo doesn't provie any information at all about contrast in the documentation that comes with its monitors ...

When we started this article, we began to single out the screens that claimed to have a contrast ratio of more than 10 000:1--already between 3 and 10 times more than the most hopelessly optimistic expectations. But the problem was, there were far already far too many of them. Instead, we've taken every manufacturer's worst offender, with one each from eleven different firms. Only Samsung managed to get two, but that's the price you pay for being the world leader.

In this chart, we put their claimed contrast ratios (blue bars with red labels) up against the results we actually measured in our lab (red bars with black labels). As you can see, almost without exception, the real figures barely even make it onto the chart.

Red: manufacturers' promised figures. Black: our lab results.

What's immediately obvious from the graph is that, apart from a few exceptions, whatever contrast ratio the manufacturer actually claims in their documentation, the vast majority of monitors have an average contrast ratio of around 830:1 when we test them in our lab. These figures are closer to the 'typical' values which are also sometimes found in the tech specs (see inset).

We're not out to name and shame the monitors that are in the list above. All of the manufacturers we contacted agreed to take part and were happy to have us compare their specs with the real results from our labs. We made the list for several resons:

to see if we'd got it wrong: maybe we weren't looking at the right specs after all?
to encourage manufacturers to respond and change their policies
in the hope that we'd be able to remove monitors from the list one by one as manufacturers decide to swap the place of typical and dynamic contrast (which we'd actually like to get rid of entirely, unless it's handled more reasonably)

So then, Acer, AOC, Asus, Dell, Hyundai, Iiyama, LG, Medion, Philips, Samsung and ViewSonic: if you have a change of heart, let us know, and we'll change things here too!

Whose fault is it?

But why do manufacturers fill up their marketing with meaningless claims about dynamic contrast? What's the point of putting the emphasis on this value, or even including it all, when in reality it has no place there at all? If you agree to let them talk off the record, almost everybody in the industry is prepared to agree that dynamic contrast makes no sense. Instead, they place they blame in four different places:

purchasing managers in large IT departments, who refuse to place huge orders unless they see enormous contrast ratios that are as unrealistic as they are useless.

the competition: as soon as the 'others' start upping the stats, everybody feels like they have to do the same. It's a bit like illegal drugs in sport.

regular consumers who want to see huge numbers. For Joe Public, the more zeroes there are at the end of the number, the better. Here, it's the same story with the number of Megapixels on a digital camera's sensor.

salespeople, who with no better arguments to push a particular monitor, fall back on reeling off big numbers to impress clients.

In short, everybody but the manufacturers themselves are to blame. And what if everybody decided to bring things back to normal? We're not saying that any one company is to blame: as we've seen, it's a collective problem. We just want everyone--users, professionals, manufacturers--to realise that by chasing after shadows, they end up creating a vicious circle that's to nobody's advantage. If there's nothing to separate a great monitor from a dreadful one on paper, both of them will suffer.

What is a good contrast ratio?

1000:1 is more than enough for everyday use. At that level, when white areas of the screen are 200 cd/m², black areas are just 0.2 cd/m². For imaging professionals, who tend to set their screens to 100 cd/m², black areas produce just 0.1 cd/m² of light. That's an absolutely perfect result, and anybody who claims any better (apart from the Samsung F2380M), is merely making it up.

Four screens with good contrast ratios--that we've checked ourselves!