Monitors viewing comfort : CCFL backlighting versus LED backlighting ?

Started Mar 5, 2013 | Discussions thread
NewsyL Veteran Member • Posts: 5,733
Re: Bottom line ?

alpshiker wrote:

noirdesir wrote:

afterburn wrote:

But this is a public forum where people voice opinions to questions. My reply was my opinion and I even indicated it was my opinion. You don't get to chose which opinion is crap and which is not because nobody has absolute truth, not even you. Each opinion, right or wrong, is equally valuable in a discussion. The whole idea of public forums is that you can get enough different opinions to form your own, not that everybody agrees with everybody.

Except that it was not clear in your post whether you were presenting your personal opinion or a large consensus opinion. If you present something without qualifiers, it is generally assumed to be something largely undisputed and not a personal opinion.

If you don't like or can't handle other people's opinions, don't go strolling on public forums. Have a good day.

What we don't like is presenting personal opinions as large consensus opinions.

Hey guys, I hate to disrupt you but maybe I can narrow my question to this:
I gather from your posts (thanks a lot btw !) that LEDS are brighter than CCFL, more uniform, have longer lasting life, more accurate colors, and there is no doubt that they are the future in TV sets and monitors (probably with OLED). What I could gather however is that they are currently implemented in monitors in such a way that those monitors can be used in bright light conditions, for that's where LEDS clearly show their superiority over the former CCFL backlighting. The problem comes when you want to use those monitors in dimm light environments such as an ordinary image lab, right ? In order not to toast ones single pair of eyes, the brightness has to be reduced to minimal values. But the fact is that LEDs can't be dimmed. They have their optimal functioning at a rated power, and to simulate dimming, one has to induce a flicker by switching feed on/off at Herzial speeds. And even if the brain can't catch the fast flicker, the eyes will and they might tell you it's not good. Am I right ?
That would explain why some users of those monitors don't notice the flicker, when others will. When the monitor is set at full brightness, LEDs are continuously switched on and they don't flicker. But when you start tweaking the monitor settings, that's when flickering appears, proportionally to the dimming that is imposed to the LEDs.

So here's the bottom line I come to :

— Use a LED monitor if you work in a bright environment, where you will keep the monitor set at high brightness.

— Otherwise, if the monitor has to be dimmed a lot, it is advisable to stay on the CCFL route, until perhaps monitor manufacturers will bring low light level LED monitors to the market, designed for those particular working conditions.

Does that make sense ?

No, you can't go by the rules of thumb you have there.

There are good and bad in both CCFL and LED back lit monitors.

For starters, both CCFL and LED can be excessively bright at 100%, way more than most people require indoors in a light controlled room. If you're not editing in a light controlled room, you're just begging for trouble. Even in a office environment you shouldn't have to go above 180 cd/m2 and many of these monitors can go to 400 cd/m2 at 100% brightness. Pointedly... if you're doing serious editing you need to have controlled lighting, blinds on windows, and avoid a room with colorfully painted walls.

Both CCFL's and LED back lit monitors can be excessively bright at 0% brightness, yes, ZERO percent. It is the BOTTOM end minimal brightness you should be more concerned with in order to avoid the "Dark Prints" issue with edited images. Google that.

As stated in another post here, a common level of brightness is between 90 and 120 cd/m2. A lot of monitors cannot get below 120 cd/m2. For example, when new the much praised HP ZR24w with CCFL back light cannot go below about 135 cd/m2 using the brightness control alone. The Dell U3011 CCFL... 128 cd/m2. The ASUS PA246Q CCFL... 127 cd/m2. All approximate figures.

Then there are the LED back lit units - the Dell U2312HM... 114 cd/m2, the ASUS PA238Q... 135 cd/m2, among others.

Of course, one way to deal with a monitor that is too bright at 0% is to increase room lighting to match the monitor.

It seems that a lot of the recent (last 18 months) LED back lit units do have a good minimal brightness down to 60 cd/m2 or lower at 0% brightness. HOWEVER, some of them accomplish that using a Pulse Width Modulation (PWM) technique to lower brightness where the LED's are turned off for a fraction of a second and back on again. Some people can perceive this as a flicker effect and for them it can be very fatiguing. Hence, the better monitor review sites are now testing for this method of reducing brightness. Read about it here...


Something else..... gamut coverage - standard sRGB and wide gamut (WG).

Most CCFL back lights offer reasonable coverage of the gamut they are designed for. Typically about 96-98% (measured) for standard sRGB gamut monitors and about 100% (measured) of sRGB and 100% of AdobeRGB for wide gamut monitors.

LED's have not been quite as good. Up to a couple of months ago a typical white LED provided about 94-95% (measured) coverage of the standard sRGB gamut. These sRGB units also have a notable spike in the blue spectrum that has to be compensated for.

With wide gamut monitors, a RG+B-LED back light could do about 100% of sRGB and AdobeRGB. RGB-LED back lit monitors are rare and very expensive.

In the past 2 or 3 months we've seen some monitors introduced with the latest generation of LG Display's IPS panels and a new back light system. The new white LED's provide about 98-99% coverage of the standard sRGB gamut while a new GB-LED provides about 100% of the sRGB and AdobeRGB spaces in a wide gamut monitor. These are discussed in reviews of the Dell U2413 (WG), U2713H (WG) and U2713HM (sRGB) monitors on TFT Central. Costs for the GB-LED back lit wide gamut monitors are much much lower than seen with the older RG+B-LED system. I expect a slew of new monitor introductions or updates due the new GB-LED system.


You're going to have to do a bit of homework....


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