Contrast Ratio

[icor1031]

Please help me understand the importance of a high contrast ratio.
How significant is it / how much does it matter? How would you explain the effect? etc.

Thanks.

 

[evilsofa]

In the simplest terms, the contrast ratio measures the blackest black versus the whitest white that the display can make.

Realistic contrast ratios for LCD monitors range between something like 800:1 to 1200:1, maybe a little more these days, but getting over 1200:1 on an LCD is hard. The marketing departments love to manipulate the hell out of the numbers to make their displays seem better on paper, so you'll see ridiculous claims like 8,000,000:1 on a $250 monitor (yeah, Acer, I'm talking about you).

A common trick for both TVs and monitors is to report the ratio that Dynamic Contrast can do. You know those annoying TVs where if a series of dark scenes are being shown, you can see the brightness of the TV being adjusted up and down? That's Dynamic Contrast, often renamed to something else to hide the fact that it's just Dynamic Contrast trickery, and marketers can use it to inflate the contrast ratio. You should always turn it off on TVs, and you should definitely never, ever use it on monitors. It's usually turned off by default on monitors and there solely for the bullshit contrast ratio marketing numbers.

The other trick, which is pretty much universal, on LCD displays is to just make the display extremely bright. It's difficult to make the blacks blacker (which is one of the fundamentals of what sets apart the good monitors from the bad), but really easy to make the whites whiter by jacking up the brightness of the monitor to an intolerable level. The best brightness settings for most LCD monitors are 20% or less, often 0%. The only good thing about this is that it allows the monitor to last longer, for they do fade in brightness with age.

It's gotten bad enough that you should just disregard contrast ratios as reported by the display makers and find out from reviews what the real contrast ratios are,

 

[icor1031]

Hey, mate.

I understand all of that stuff. Maybe that's all there is to know?

But, I assumed the contrast ratio also affected colors. Does it? Is it significant (does it have much impact on the perception of image quality)?
I ask, because I hear people saying that the Samsung 4k has poor contrast.

Thanks for taking the time!

 

[Nenu]

How dark black can go affects how darker colours look. The darker the better as it makes colours look richer.
(think of it the other way round, the brighter black is, the more colours look washed out, then reverse it)
It also affects your perception of darkest black.

How bright white can go affects how brighter colours look and affects your perception of white.

Fitting a brighter light behind the same LCD panel wont increase the contrast ratio because it will increase black and white by a similar ratio.
Better contrast ratio displays are mostly defined by how dark they go.
Although Sony recently demoed a new type of lighting system that adds extra light for very bright scenes, this also increases the contrast ratio without affecting black levels, but this type of boosting is rare.

 

[icor1031]

How dark black can go affects how darker colours look. The darker the better as it makes colours look richer.
(think of it the other way round, the brighter black is, the more colours look washed out, then reverse it)
It also affects your perception of darkest black.

How bright white can go affects how brighter colours look and affects your perception of white.

Fitting a brighter light behind the same LCD panel wont increase the contrast ratio because it will increase black and white by a similar ratio.
Better contrast ratio displays are mostly defined by how dark they go.
Although Sony recently demoed a new type of lighting system that adds extra light for very bright scenes, this also increases the contrast ratio without affecting black levels, but this type of boosting is rare.

Thanks, mate.

 

[Zangmonkey]

Hey, mate.

I understand all of that stuff. Maybe that's all there is to know?

But, I assumed the contrast ratio also affected colors. Does it? Is it significant (does it have much impact on the perception of image quality)?
I ask, because I hear people saying that the Samsung 4k has poor contrast.

Thanks for taking the time!

Your eyes are more sensitive to luma (dark to light) than chroma (hues of color)

A display which has poor contrast may struggle to shade colors well. Accurate colors depend upon accurate contrast.

When it comes to TV and movies, most have color encoded over top of contrast... so if you have bad contrast you also have bad color.

 

[Zangmonkey]

Fitting a brighter light behind the same LCD panel wont increase the contrast ratio because it will increase black and white by a similar ratio..

Fitting a bright light will decrease contrast ratio because brighter backlighting is additive, not multiplicative, so bleed is additive.

The ratio is, generally, the ft-lambert of "black" to "white".... if you make both the blacks *and* whites brighter then your ratio decreases.

Imagine a baseline of black=10 and white = 1000 (ratio 1:10), this is a property of how much light is blocked in an LCD.

make everything brighter! blacks are now 210 and whites are 1200 (ratio 21:120 ~ 1:6)

 

[Outbreaker]

Contrast is as important as 6-bit vs 8-bit colors.
http://www.microsofttranslator.com/...o/2011/10/09/plasma-vs-led-test-practic/all/1
https://www.youtube.com/watch?v=sWqD1zb9tvc
It's hard to film the contrast differences with a normale camera that's why most Monitor review websites ignore it and give a 700:1 contrats Monitor a 5/5 rating and a 3500:1 Monitor 3/5 rating.

 

[DrRamtop]

Realistic contrast ratios for LCD monitors range between something like 800:1 to 1200:1, maybe a little more these days, but getting over 1200:1 on an LCD is hard.

It's worth pointing out here that this only applies to TN and IPS panels. Modern VA screens regularly achieve in excess of a 3000:1 ratio in independent testing.