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Discussion Starter · #1 ·
Hi folks. Been visiting and reading all the great info. and content on this forum for some time, but have never posted.


I would consider myself a newbie regarding display technologies (compared to you forum regulars)...however, from all the learning I have done visiting this site, I know enough to ask the right questions (I think).


Can "you all" comment on the following questions I have, which have been buggin me:


A) Why exactly do thousands of dollars RPTV sets need to be professionally calibrated after purchase and installation? I mean, given the present state of technology, why can't the manufacturer "hard-wire" the correct industry standard conventions for color, contrast, black levels, etc. into the set during production. How hard can that be? Perhaps this is set by the manufactuer...if so, then what changes occur during shipment, storage, etc. which necessitate re-calibration by the new owner after he/she has installed it in the home?


This is especially confusing to me with regards to the Digital RPTV Technology (DLP, LCD). I would think that these paramaters could be dialed in by the manufacturer at final inspection, QC stage, prior to shipment. Again, assuming this IS done by the manufacturer...why do these settings "drift" or get out of whack, and require re-calibration.


If they are NOT done by the manufaturer...what technicall limitation is there which prevents them from doing it, and providing a fixed, consistent product to the consumer that is already set up to the "accepted" ISF standards?


B) Why is color measured in temperature. I presume the "K" means the units are in Kelvin. Color is a result of the electro-magnetic spectrums frequency, not temperature. With that said...I do realize that higher temperatures will cause the black-body radiation curve to shift, with peak intensities occurring at higher frequencies.


C) Are there any papers or links you could provide which would give me a better understanding how proper picture quality is established and why the approved standards are what they are.


Thanks in advance.
 

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Quote:
A) Why exactly do thousands of dollars RPTV sets need to be professionally calibrated after purchase and installation? I mean, given the present state of technology, why can't the manufacturer "hard-wire" the correct industry standard conventions for color, contrast, black levels, etc. into the set during production. How hard can that be? Perhaps this is set by the manufactuer...if so, then what changes occur during shipment, storage, etc. which necessitate re-calibration by the new owner after he/she has installed it in the home?
Ideally a set has to be burnt-in first before being calibrated. That would hold up the assembly line and increase the cost. And with CRTs the magnetic field is different from where it's made to where it will be.


The truth is that most consumers are just not that picky, except for us snobs here.
 

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Discussion Starter · #4 ·
Man...I thought folks like Rogo and other forum videophiles would be all over this with technical pearls of wisdom.


I guess my questions are too stupid?
 

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I'm not up to the level of some of the folks on this forum, but I can give basic answers to your questions.


Q1: Why don't manufacturers dial in perfect display settings? The biggest reason is that they "tune" their picture to stand out on the display floor. Notice that I didn't say "look good on the display floor". They know that there are fifty TVs on display and theirs has to stand out. If everybody tuned their picture to ISF standards, then the only thing that would make a difference would be picture quality. We can't have that! So an "arms race" begins where everybody starts turning their picture up and up and up... etc...


Q2: The K that you see does, in fact, refer to the Kelvin scale. It is referring to the color that would be given off by a black-body object at a certain number of degrees Kelvin. It is being used to refer to the "color" that gray should be.
 

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>>C) Are there any papers or links you could provide which would give me a better understanding how proper picture quality is established and why the approved standards are what they are.



Check with Minolta. They have the color charts used by ISF, and are known and respected ancient ones, in the color industry. TI uses them to custom-make the lenses used on their quarter-million dollar DLP projectors for the movie industry.


Also check my website, below, in the Nuts and Bolts section. You might also enjoy the photo of the image on my 65" Panny, cover page.



FPTV pjs and RPTVs are like Lamborginis - lots and lots of fine tuning needs to be done, for the final product to really rear its beautiful, ugly head. We videophiles can see the differences, but Joe Sixpack - and his kids whose baby sitter the RPTV is, in many cases - cannot. He has hungry mouths to feed and can't be bothered, and HE is the one buying most of the RPTVs out there, and driving down the price. Let's hoist one for him, those of us who have gotton good deals on our purchases because of him and his incredible buying scale. Compared to him, our videophile purchases are just a drop in the bucket.



Most brands overscan their images, to hide the fact that their point systems are woefully underfunded - underscaled and undermemoried - compared to the much more expensive ceiling pjs. Part of what we calibrators do first off is to restore the lost areas of image that most RPTVs don't even come close to delivering, OOB.


Which completely hoses whatever precision the OOB image had to start with. It takes an hour or 2 just to get that back to reasonable precision with the properly sized picture, before we can even start the high precision convergence process.


But restoring your lost pq area also raises your resolution, because it jams the pixels in there tighter, both horizontally and vertically, when you restore the proper sizing to both.


All of which is endemic and required of the genre, when the red image is coming from/projected from the left, the blue is coming from the right, all 3 images are coming from down below to up above, and the throw distance between CRT face and screen is WAY too short for lots of fisheye to not be inherent - all of which distort the image that hits the screen accordingly, making an unconverged picture a complete mess.


I could go on and on, and it would include the insightful responses above, which I agree with wholeheartedly.


Bottom line is, RPTVs need LOTS of care and feeding. But properly treated, there's no better picture out there - no picture out there, in the fixed pixel realm, that's better than a finely calibrated CRT picture. Fixed pixel devices - aside from flat panel devices, for spacial considerations in interior decoration - are industry evolution's answer to not having enough fullservice calibrators to adequately service and maintain the much finer CRT genre. They are the next best thing to CRTs, but still have not eclipsed CRT in true high resolution potential, nor in their ability to capture true blacks and dark grays the way CRTs do.


It's all worth it in the end, the calibration process, and CRT-based units - even fully calibrated - are still markedly cheaper than fixed pixel devices.



Mr Bob
 

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Tritium-

on the issue of color-- The temperature refers to balance of color components of "white"; so what the tv is displaying as "white" might be shifted slightly from what is intended by the movie people on the recorded media (6500k). The temperature of white also varies as you change brightness levels of white on a given monitor.


* "As I understand it"
 

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Well, white and gray, actually.



In their attempt to make their TVs stand out, they want to make them look "BRIGHTER" than others, and so they make the grayscale - B/W info, not color - bluer than white should be. Just like the headlights out there these days that are blue, and stand out from the crowd of normal headlights.


Then they do red push, to make the fleshtones not be totally decimated by the blue whites.



Mr Bob
 

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Quote:
Originally posted by Mr Bob
>>



Most brands overscan their images, to hide the fact that their point systems are woefully underfunded - underscaled and undermemoried - compared to the much more expensive ceiling pjs. Part of what we calibrators do first off is to restore the lost areas of image that most RPTVs don't even come close to delivering, OOB.


Which completely hoses whatever precision the OOB image had to start with. It takes an hour or 2 just to get that back to reasonable precision with the properly sized picture, before we can even start the high precision convergence process.


But restoring your lost pq area also raises your resolution, because it jams the pixels in there tighter, both horizontally and vertically, when you restore the proper sizing to both.


All of which is endemic and required of the genre, when the red image is coming from/projected from the left, the blue is coming from the right, all 3 images are coming from down below to up above, and the throw distance between CRT face and screen is WAY too short for lots of fisheye to not be inherent - all of which distort the image that hits the screen accordingly, making an unconverged picture a complete mess.


I could go on and on, and it would include the insightful responses above, which I agree with wholeheartedly.


Bottom line is, RPTVs need LOTS of care and feeding. But properly treated, there's no better picture out there - no picture out there, in the fixed pixel realm, that's better than a finely calibrated CRT picture. Fixed pixel devices - aside from flat panel devices, for spacial considerations in interior decoration - are industry evolution's answer to not having enough fullservice calibrators to adequately service and maintain the much finer CRT genre. They are the next best thing to CRTs, but still have not eclipsed CRT in true high resolution potential, nor in their ability to capture true blacks and dark grays the way CRTs do.


It's all worth it in the end, the calibration process, and CRT-based units - even fully calibrated - are still markedly cheaper than fixed pixel devices.



Mr Bob



I agree with this totally!!!


Good post Mr. BOB.
 

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Discussion Starter · #10 ·
Thanks to one and all for their input and knowledge.


Could anyone steer me to some links where I could learn more advanced topics about:


A) HDTV in general (scan rates, vertical/horizontal resolutions, interlacing vs progressive, etc.

B) Home Theater for the intermediate (or beginner)


Loraan: Not sure I completely agree with your answer to my question regarding the color temp. vs blackbody radiation curve. Higher Temperatures will "skew" the curve towards higher peak intensities at higher frequencies (shorter wavelengths). I guess that more "blue" just means that the maximum point on curve (frequency vs intensity...or spectral density) is peaking at "x" angstroms, corresponding to our eyes registering more blue??


Thanks again,

Tritium
 

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Quote:
Originally posted by Tritium
Not sure I completely agree with your answer to my question regarding the color temp. vs blackbody radiation curve. Higher Temperatures will "skew" the curve towards higher peak intensities at higher frequencies (shorter wavelengths). I guess that more "blue" just means that the maximum point on curve (frequency vs intensity...or spectral density) is peaking at "x" angstroms, corresponding to our eyes registering more blue??
It's well explained on the Digital Video Essentials DVD. I can't post links until I've made 5 posts, so I can't point you to any links, but try Google searches on "color of white" and "color temperature television".
 

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>>I can't post links until I've made 5 posts, so I can't point you to any links



That should take NO time at all on a board like this.


Welcome!



Mr Bob
 

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>>Could anyone steer me to some links where I could learn more advanced topics about:


A) HDTV in general (scan rates, vertical/horizontal resolutions, interlacing vs progressive, etc.

B) Home Theater for the intermediate (or beginner)



Check out Secrets of Home Theater.



Mr Bob
 
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