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why dont displays just show the signal they are given unaltered?

post #1 of 29
Thread Starter 
Hi my question is why don't displays just show what the source feeds it unaltered? wouldn't that be easier to design instead of messing up the image so much since eveyone is trying to aim for an unaltered image
post #2 of 29
This article address your question.
http://www.tlvexp.ca/2011/12/why-tvs-are-not-calibrated-from-factory/
post #3 of 29
Thread Starter 
thanks. i am also interested in the technical side, like how they are made and what determines their color accuracy. Their structure and components, etc. Basically how they are made and how their components work.
post #4 of 29
The 'display screen' needs to know what colour it 'should' display for any given colour value.
The 'raw' screen will have a totally un-calibrated response if it is not told what it should show.

What exactly is 123, 234, 025 RGB?
What should it really look like?

But, the techniques (and accuracy) used by manufacturers to 'calibrate' their displays varies wildly.

So, the whole aim of later calibration, as done by the members of this forum, is to attempt to better the standard 'calibration' the manufacturers use.

The best display calibration is to treat the 'display' as a dumb screen, with the minimum of integrated controls, and then use display profiling and a 3D LUT to fully calibrate the display.

This is basically what we do in the professional market - for the displays used for film grading.

Any help?

Steve
post #5 of 29
Our displays use a device dependent color space (RGB) and a color result will depend on equipment, setup and procedures to produce it VS a color space where a color's coordinates used to specify the color will produce the same no matter where they are applied (i.e. CIELAB).
post #6 of 29
Quote:
Originally Posted by Light Illusion View Post

The best display calibration is to treat the 'display' as a dumb screen, with the minimum of integrated controls, and then use display profiling and a 3D LUT to fully calibrate the display

... and the rest of us that don't see the point of adding a $4000 processor in front of a $550 display, just muddle through with our "integrated controls."
post #7 of 29
Quote:
... and the rest of us that don't see the point of adding a $4000 processor in front of a $550 display, just muddle through with our "integrated controls."
The eeColor box is only $600...

But I do understand what you mean.
I was just pointing out the realities of home TVs, as sad as that is.

Steve
post #8 of 29
........ or just use a calibration disk to set the basics from a blu-ray player with no extraneous processing being done by either the tv or the blu-ray player. Source is always going to be the uncontrollable factor in watching television. The best calibrated set can look like crap if the source feeding it is terrible.
post #9 of 29
All major film (DVD/Blu-Ray) and most quality TV source footage is graded on well calibrated displays...

If you have a well calibrated display at home, calibrated to match such professional displays, what you will see is what the production intended - and isn't that what this is all about?

rolleyes.gif
post #10 of 29
Thread Starter 
Thanks, I'll repost something from another one of my threads since it also applys here.

me: "This was very informative, i hope this tv hunt comes to an end soon. Just sucks that the tv experience for viewers is at such a low that such measures have to be taken in order to get accurate representations of video and photography content and it also puts this sort of burden on artists since they can't show their work to the world without it being hammered by display devices."



so if i got this straight there are devices, ex: the color box that can manipulate displays apart from their normal controls to achieve accurate repesentation of content. Does it alter the tv itself or does thebox have to stay with the tv at all times.

I'm interested in these proffessional calibration methods.

It just bothers me that at this day and age of video and images people all over the world are viewing these altered images. I don't know why but it does. I want to get into film making soon and i would feel uncomfortable knowing my material will not be seen to it's fullest by the wide audiances.
Edited by steelclaw174 - 12/8/12 at 12:04pm
post #11 of 29
Just keep in mind that a professionally calibrated tv will give you the best video performance within the video control settings that the tv has. But, it is not forever. As electronics age, re-calibration will be necessary to maintain the image fidelity. The length of that time is dependent upon many factors, none of which the end-user has any control over.
post #12 of 29
Quote:
Originally Posted by steelclaw174 View Post

so if i got this straight there are devices, ex: the color box that can manipulate displays apart from their normal controls to achieve accurate repesentation of content. Does it alter the tv itself or does thebox have to stay with the tv at all times.
I'm interested in these proffessional calibration methods.
.

The eeColor Processor stays with the TV. The processor both holds and processes through a lookup table(s) and the box resides between the signal source and the display. Everything within the display that has an Auto function is turned off to minimize any manipulation being accomplished by the display itself. The lookup table then adjusts an input signal and sends that adjusted signal to the display so that the picture you see is as correct as the display is capable of providing. This technique is more accurate than using the display controls because many, many more points of reference are in use.
post #13 of 29
^^^^ ok. so it's another device (and another piece of hardware situated somewhere around the tv) per source to maintain video fidelity over the life of the tv?
post #14 of 29
Quote:
Originally Posted by Otto Pylot View Post

^^^^ ok. so it's another device (and another piece of hardware situated somewhere around the tv) per source to maintain video fidelity over the life of the tv?

"Over the life of the TV"? No, and neither would any other type of calibration work forever, but it's a great question. A LUT takes a signal and outputs it to the TV to create the correct picture. As the display ages and the electronic components drift the picture quality would drift as well. A new profile of the display would have to be measured and a new LUT would have to be created. How often? Depends.... A home LCD, maybe never. A projector, depending, maybe once a year or so. A post house transforming your favorite movies into Blu-Ray discs, maybe once or twice a month.
post #15 of 29
Ok. But please forgive me because I still don't see the utility of eeColor Processing? It's late so maybe I'm missing something obvious. Don't mean to start an argument here I'm just trying to understand.
post #16 of 29
Quote:
Originally Posted by Light Illusion View Post

The eeColor box is only $600...
But I do understand what you mean.
I was just pointing out the realities of home TVs, as sad as that is.
Steve

I'll concede the eeColor point (I was thinking Lumagen,) but raise you that at many "modern" displays have "integrated controls" that are light-years ahead of what were available a few years ago.

There's a point of rapidly diminishing returns. smile.gif
post #17 of 29
Quote:
Originally Posted by Otto Pylot View Post

Ok. But please forgive me because I still don't see the utility of eeColor Processing? It's late so maybe I'm missing something obvious. Don't mean to start an argument here I'm just trying to understand.

Just think of it as a video processor... works the same way, except you have to measure color with software that runs on a PC and after the measurements are calculated into a LUT (look-up table), the LUT is downloaded to the eeColor box. Signals pass through the eeColor box on the way to the TV so you'd typically want the eeColor box to be the last thing in the signal path before the TV with source switching done elsewhere (not in the TV). There's really no "per source" calibration capabilitiy since most consumer sources can't be calibrated. Like a video processor, the eeColor box will make the display accurate, but if one out of the 4 sources you use is inaccurate, you'd either have to have some way to calibrate that source, or there would have to be some way for your computer to feed the test patterns to that source for display so a custom LUT just for that 1 source could be generated. And the eeColor box would have to have multiple LUT memories you could switch between (I don't remember if it can do that or not).

The LUT is the final result of all the calibration adjustments that you would put into a Video Processor (but probably much more detailed with adjustments at many more points for grayscale, gamma, and color). So you can't adjust the eeColor box like you adjust a video processor, but you can use external software to display patterns, make measurements and create a LUT that is downloaded to the eeColor device. When introduced intiially, the eeColor device was $1500 (if I recall correctly, maybe it was $1600) so $600 is a huge improvement in cost.
post #18 of 29
Quote:
Originally Posted by HDTVChallenged View Post

I'll concede the eeColor point (I was thinking Lumagen,) but raise you that at many "modern" displays have "integrated controls" that are light-years ahead of what were available a few years ago.
There's a point of rapidly diminishing returns. smile.gif

Except most of those controls in the TV are total garbage or very limited in many cases, and worse than those in the eeColor/Lumagen. I have a Sony projector here right now and it has grayscale control (only 2 points) and a CMS in their Real Color Processing. The RCP adjustments go from -30 to +30, but if you go back +/-5, it turns to garbage. Same with JVC when you do fine gamma adjustments, Samsungs if you push them too far, etc... They all have these controls, but they usually don't work right. Those in the Lumagen and eeColor actually work, which is a big difference.
post #19 of 29
Quote:
Originally Posted by Doug Blackburn View Post

Just think of it as a video processor...

Thanks Doug. I can see the utility of it now but it's another piece of hardware in the family that probably wouldn't pass the WAF, so..... frown.gif
post #20 of 29
Quote:
Originally Posted by Smackrabbit View Post

Except most of those controls in the TV are total garbage or very limited in many cases, and worse than those in the eeColor/Lumagen. I have a Sony projector here right now and it has grayscale control (only 2 points) and a CMS in their Real Color Processing. The RCP adjustments go from -30 to +30, but if you go back +/-5, it turns to garbage. Same with JVC when you do fine gamma adjustments, Samsungs if you push them too far, etc... They all have these controls, but they usually don't work right. Those in the Lumagen and eeColor actually work, which is a big difference.

Perhaps this is an area where doing one's homework helps ... and may save you $600 to $4000 in the process. wink.gif

Furthermore, that $4000 "improvement" isn't going to be noticeable unless you're viewing two displays side-by-side, so ... ????
post #21 of 29
Quote:
Originally Posted by HDTVChallenged View Post

Perhaps this is an area where doing one's homework helps ... and may save you $600 to $4000 in the process. wink.gif
Furthermore, that $4000 "improvement" isn't going to be noticeable unless you're viewing two displays side-by-side, so ... ????

It's not $4000. The Lumagen/CalMAN/C6 solution was far cheaper than that during their Color Cube introduction. Even the "regular" price is substantially less than $4000. As is Light Illusion's very intriguing software with the eeColor box. Matter of fact I may well have gone with LI's setup had I known.

Believe me, you don't need a side-by-side comparison to notice an improvement! Of course I come from an un-calibrated RS20. I never had the patience to go through a proper manual calibration. But going from an un-calibrated RS20 to a 125pt 3D LUT/21pt gamma calibrated RS20 is the most phenomenal improvement I've ever seen in my HT. It is a far bigger difference than going from my trusty RS1 to the RS20. My wife and I watched Pride & Prejudice right after the auto-cal and she said it was "stunning" and "gorgeous". I had just spent thousands of dollars (no, not $4,000) on the calibration suite and my wife thought it was totally worth it.

I can wax poetic about the characteristics of the image that were so impressive if you want. But my two points are:

1) It's nowhere near $4000.
2) You do not need a side-by-side comparison. It will hit you right between the eyes.
post #22 of 29
I'm in another thread where someone has asked a question I can't answer. I am very interested in an answer as I'm sure HDTVChallenged is. And that is: How much better is a 125 pt LUT calibration than a calibration that uses only a single color point for primaries and secondaries and relies on the display's color decoder for the rest?
post #23 of 29
Quote:
Originally Posted by erkq View Post

It's not $4000. The Lumagen/CalMAN/C6 solution was far cheaper than that during their Color Cube introduction. Even the "regular" price is substantially less than $4000. As is Light Illusion's very intriguing software with the eeColor box. Matter of fact I may well have gone with LI's setup had I known

1) It's nowhere near $4000.
Direct from spectracal's site: $6000+ for the combo you just mentioned. The cheapest Lumagen based combo package is currently $3000+. Get your facts straight.
Quote:
2) You do not need a side-by-side comparison. It will hit you right between the eyes.

I meant compared to a fully calibrated (non-3D LUT version) display. Of course you'll (probably) notice the difference from any non-calibrated display.

Yes there are some may still be some truly "horrible" displays around. That doesn't mean you need to throw another $6000 at them to "fix" them, it just means you should have spent more time researching displays before purchasing one. ... as always YMMV. smile.gif
post #24 of 29
LightSpace Home Cinema Calibration with an eeColor box is under $3000 USD... (at the present exchange rate)

cool.gif
post #25 of 29
Quote:
I'm in another thread where someone has asked a question I can't answer. I am very interested in an answer as I'm sure HDTVChallenged is. And that is: How much better is a 125 pt LUT calibration than a calibration that uses only a single color point for primaries and secondaries and relies on the display's color decoder for the rest?

A good 3D LUT calibration will always improve a display's calibration, but the amount depends on the 'standard' calibration ability of the display...

Some display self-calibrate ok, while others are very, very poor.

Buzzard posted about the results he got with a 3D LUT calibration on a cheap display - see: http://www.avsforum.com/t/1437739/lightspace-cms-now-supports-lumagen-eecolor-3d-lut-4-all#post_22612302

Hope that helps.

Steve
post #26 of 29
Quote:
Originally Posted by Light Illusion View Post

A good 3D LUT calibration will always improve a display's calibration, but the amount depends on the 'standard' calibration ability of the display...

For the record, I'm not disputing that ... I'm just skeptical that it's worth it ($3000) for the Home-Theater crowd.

Clearly, it's a no-brainer for professional use (edit/grading/mastering bays.)

I have an old Sony trinitron that has perhaps the worst SD color decoder ever produced. Yet, after calibration, it's still surprisingly viewable ... (so long as you don't put it beside a more capable display.) The human eye/brain adapts quickly. wink.gif

Edit: the word is "worst" not worse eek.gif
Edited by HDTVChallenged - 12/12/12 at 12:56am
post #27 of 29
Quote:
Originally Posted by erkq View Post

I'm in another thread where someone has asked a question I can't answer. I am very interested in an answer as I'm sure HDTVChallenged is. And that is: How much better is a 125 pt LUT calibration than a calibration that uses only a single color point for primaries and secondaries and relies on the display's color decoder for the rest?

You can't answer the question because there is no answer. It's impossible to answer. What brand of TV? What model year? What model? LCD with CCFL? LCD with LED? Plasma? DLP? Projector? Flat Panel? Room lights on or off?

How linear is the TV in question? Or how non-linear? How close (or far) are the primaries and complimentaries to the aim points? How good is the grayscale? How linear or nonlinear is gamma?

You simply cannot quantify "how much better" ANY calibration is. There are just too may variables. How much better are $300 tires than $70 tires? Impossible to tell... what are you going to do with them? Race on a track or commute to work in Seattle where it rains a lot? Are they for a Yugo or a Corvette? What does "best" mean to you... tires that last 50,000 miles or more or tires that enhance handling and grip? People always want to know "What's the best ________________" but it's a damn near impossible question to answer because there are so many variables.
post #28 of 29
Quote:
I have an old Sony trinitron that has perhaps the worse SD color decoder ever produced. Yet, after calibration, it's still surprisingly viewable ... (so long as you don't put it beside a more capable display.) The human eye/brain adapts quickly. wink.gif

True... but perform a full 3D LUT calibration on the same display and flick between the two and the results would probably be rather surprising...

biggrin.gif
post #29 of 29
Lots of good info. here. biggrin.gif
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