Remeber Me
Lost Password? No account yet? Register

Private Messages

You are not logged in.

START HERE I This e-mail address is being protected from spam bots, you need JavaScript enabled to view it  |Home Calibration Services 
Home
 
 
 
 
One Installer's Opinion: Measuring Black Level...and 5 other Myths Print E-mail
Written by Terry Paullin   
Friday, 20 November 2009

black-level.jpgDiogenes is my Hero. He was, as you may recall, the little Greek fellow (circa. 400 BC) who, armed with a lantern, went running around searching for the Truth. Reports vary as to his success, but there is little question that his mission would be doublely difficult today - especially if he was confining his search to Big Box Electronics stores and gathering data according to "Sparky", the on-duty salesperson. If there were any teeth at all in the "Truth-in-Advertising" laws, our correctional institutions would be overflowing (even more than they are). All we can do is expose the nonsense from time to time and call "Shenanigans" on specific offenders. This month's column is another modest attempt at the aforementioned whistle-blowing.

The first topic, the one cited in the by-line, is more of a correction to a non-sequitur than a reveal of a nefarious marketing tactic, but it sets up a more important corollary thought, so stay with me.

1. You can't measure black!

Yup, that's right. For all the focus on this important image quality parameter, we can't truly measure it. We measure "Black Level" with light meters. If the face of a display were truly black (absent all light) we couldn't measure it! We can only measure a screen's inability to give us a true black. Even then, the "light leakage" on screen has to be above a certain (very small) level before even the best, most expensive, state-of-the-art instrumentation can quantify it.  Wordsmithing, you say? .....well maybe, but it gets me to a more important issue.

2. "A display with a measured .002 ft-L black level will produce a better C.R. (contrast ratio) in my Home Theatre than one that measures .004 ft-L"

uh, maybe not. In fact, in my experience installing and calibrating hundreds of theatres, PROBABLY not. Here's the thing. The very "best black" you are going to achieve with any display in a given environment is the "room black". We calibrate all displays with something called "Pluge" patterns that allow us to "just barely see 2% of the light output on the way to peak white. Some of the best discs provide a 1% stripe, but the difference is almost academic. The point is your room has a black level "floor" determined by the ambient light leakage from all sources that can "see" the screen, i.e., light leakage from behind curtains that don't perfectly seal off the windows, a lamp turned on in an adjacent room, the red, yellow, green and blue LEDs on the face of the equipment rack (even though it may be several feet from the screen), and even, yes, viewer's clothing. A competent product reviewer would never attempt to measure a very low black level wearing a white shirt! In other words, unless you have a pitch black dedicated theatre with a black velour cloth draped over the front of the equipment, you are probably NOT going to take advantage of that ultra-low black level specification on your new display. Truth is, it was probably manifested as an ultra-high C.R specification (based on a very small denominator). Same deal. Ya ain't gonna get it without "The Perfect Room". So while I still concur that REAL contrast ratio remains the most important parameter of those normally cited, it shouldn't be overemphasized if your light environment is like most I've seen - less than perfect.

 3. Edge Enhancement

I see this term more and more turning up on user menus as though it was a desirable feature. It's not. It's an artifact, and ALL artifacts are undesirable! It's another trick to try to improve "apparent" C.R. It puts things on the screen that weren't in the source. Turn it off.

4. BD vs. DVD ... "I can't really see much of a difference".

I (and most of you) have read the hilarious exchanges on the various forums that allege subtle differences in viewing content on Blu-ray versus standard DVD. These folks should either be rushed to the nearest Lens Crafters for emergency care or be made to realize that they may NOT see a huge difference if they are basing their observations on one of the new crop of $99 BD players connected to a $500 LCD panel with a $14 HDMI cable. All things in balance, folks. On a reference system, or even one a cut or two below in quality, the difference between BD and DVD (audio OR video) is larger than the number of mugs on facebook.

5. "Hold on! Don't buy anything. 4K is coming".

We are speaking, of course, of 4,096 lines of vertical       resolution (Uber-HD), starting to be touted in a few places. Well, so what. Any content that exists in this format, for now and for the next few years, will likely be prohibitively expensive to get to your living room - never mind the four-times-normal Studio paranoia that will have to be overcome. Unless your screen is larger than any interior wall that I have ever seen, the improvement in image quality per incremental dollar spent is simply a bad bet for now. There is so much high quality 1080 available today, if you wait for 4K, you'll never catch up!

6. Color Space. "We have 130% more colors"

Yeah, I know. I hit this one pretty hard last month, but    it remains a huge marketing "distortion", and therefore deserves another mention under this month's topic. There is only one correct color space for the vast majority of what we currently watch - High Definition television and Blu-ray movies. It is NOT as wide as it can be. Technically it's called rec. 709 and it has very specific places for Red, Green and Blue which define the palette upon which everything we watch is drawn. Over-saturation is as offensive to some as bad de-interlacing or blatant motion artifacts. Unless it can be "fixed" with one button on the remote, sets that feature "larger gamut" are worth less than those that don't.

As long as consumer electronics companies employ marketing departments, we are destined to be bombarded with "questionable" features, specifications and rhetoric. Our only real defense is to read, question and relentlessly seek out the Truth.

Diogenes, where are you when we really need you?

Keywords: Contrast Ratio, Edge Enhancement, measuring black level, vertical resolution, HDMI, color space, calibration, home calibration, ft-L

Comments
Add NewSearchRSS
danindy - Black Level   | Registered | 2009-11-20 12:02:32
Terry,
Isn't the absence of black level almost the same as trying to measure it? Just not really sure if what you say is a real eye opener. Good piece overall, but some guys at Best Buy actually know what they are doing.
alanc - You are dreaming a little   | Registered | 2009-11-20 12:18:21
Great piece! Thank you. Some of it is over my head, but this is quite helpful. One thing, you are dreaming if you think the manufacturers are going to stop the poor marketing. All they care about is putting the brightest picture on the floor to attract the eye. Refresh rates work in the marketing world.
mahlerfan999   | 69.92.155.109 | 2009-12-05 16:39:25
Item #4 sounds smug and condescending. Most people can not afford a reference display and have probably never seen a reference display. If you need a $4,000 kuro to see the benefits of blu-ray why should anyone be rushed to lens crafters?? I think that bd does look better than dvd, but I have to save that this is by far the most poorly argued defense of the format I've ever seen.

Everything else in that article was great, but that #4 is a stinker. A more appropriate response would be something like "did you know that to see the full benefits of hd you need to sit close to a large tv?" The cause of so many saying that bd is not an improvement over dvd is because many buy 32-40 inch to sit 10 feet away from it, and can't see the improvement. You don't even need a high end display, just about any hdtv will make hd shine.
enfalang123 - wedding dresses     | 66.79.163.109 | 2010-02-09 02:43:16
Thanks for taking the time to discuss this, I feel strongly about it and love learning more on this topic. If possible, as you gain expertise, would you mind updating your blog with more information? It is extremely helpful for me.
Wedding Dresses
Wedding Dresses 2010
Beach Wedding Dresses
A-Line Wedding Dresses
Strapless Wedding Dresses
Only registered users can write comments!

Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved.

Last Updated ( Friday, 20 November 2009 )
 
< Prev   Next >
 

New to TweakTV?  Start HERE

Follow tweaktv on Twitter


Playoff Football Specials

DEALS: Discounts

samsung ln46a950.jpg

 

 

 

 

 

 

 

Best HDTV for ME?

 


Discounted HDTV's

Need Help Choosing?

sonykdl-52xbr9.jpg

 

 

 

 

 

 

Best HDTV for ME?

Tweak TV Popularity Polls

Which is the best HDTV?
 
Who manufactures the best LCD TV?
 
 

 
V2.0