Using highest backlight setting for the best calibration accuracy? - Page 2 - AVS Forum
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post #31 of 43 Old 01-26-2014, 03:45 PM - Thread Starter
 
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Originally Posted by spacediver View Post

then increasing the value from 1-8 does not add equivalent light to black and white levels, as you stated it did.

CR = WP/BP. From setting to setting WP and BP need to increase by an identical amount to provide the same CR.
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post #32 of 43 Old 01-26-2014, 03:48 PM - Thread Starter
 
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I'm not going any further to prove my point or else someone will try to point this and that and we'll be talking about my relationship with my mother and how many siblings I have and which medications I take. I got my answer - thanks to all who replied with an answer without all the BS.
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post #33 of 43 Old 01-26-2014, 04:49 PM
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Quote:
Originally Posted by MonarchX View Post

CR = WP/BP. From setting to setting WP and BP need to increase by an identical amount to provide the same CR.

You keep demonstrating ignorance in your questions and statements. That's why I try to explain things to you. And, yes, the answers to your question are in what I post, but you're so self-absorbed you can't get past your hatred of my trying to help you get past this awkward stage. Like a 14-year-old who suddenly hates his parents for no good reason. It has been my experience that the best answers I've ever gotten to questions I've asked came from people who provided information... knowledge... and made me think about how that applied to my question. You asked a question without a yes or no answer - a question that required knowledge to understand the issues. If you knew as much as you keep telling us you know, you would not have needed to ask the question in the first place.

Lets just look at your statement quoted above... increase both black level and white level by the same amount provides the same CR...

No, it does not.

a) Black level = 0.03 fL white level = 30 fL CR = 1000:1

b) Black level = 10.03 fL whitel level = 40 fL CR = 3.99:1

All I did in case b was add an equal amount of light to both values, just like you said.. 10 fL added to black and white... which is an equal amount of light. Clearly the contrast ratios are not the same when you add an equal amount of light to black and white

For case b to have a 1000:1 contrast ratio with 40 fL for white, you could only add 0.01 fL to the black level (0.04 fL total). So in this case, as in all cases, the black level has far more influence on contrast than anything else. Just as I posted earlier. There is no universe I know of where 10 fL = 0.01 fL. (Yes, I'm being a smartass and you deserve it in this case).

The real issue here is that you keep thinking you are asking questions with yes or no answers and that's rarely possible when discussing calibration unless you ask something like "Are .3127 and .329 the right xy coordinates for d65?" .

And don't bring the 444 / 422 discussion into this - that whole thread was loaded with people (probably called in by you) to beat down the big bad ogre... who is still correct, by the way. None of your computer video boys could explain or even attempt to explain (or even acknowledge) why a page of colored text originating on a 420 Blu-ray disc looks pristine on a video display (in 422 mode) while a page of colored text from a computer degrades if the computer sends anything but RGB or YCbCr 444 - which was my point all along... 422 is not the problem, if there is a problem, it's coming from something other than 422 color decimation itself - like not doing it right and right includes being able to use 16-240 in Cb and Cr channels rather than being limited to 235 as the luminance channel is). But you (and the other lap dogs you called in) weren't interested in logic or knowledge, only in beating down the only voice of reason in a crap-storm of ignorance and assumptions. And this thread is headed in exactly the same direction.

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post #34 of 43 Old 01-26-2014, 04:55 PM
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Quote:
Originally Posted by MonarchX View Post

CR = WP/BP. From setting to setting WP and BP need to increase by an identical amount to provide the same CR.

So if your black level is 0.1 nits and your white levels is 100 nits, and you increase the black and white levels by 1 nit, you'll end up with the same contrast ratio?
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post #35 of 43 Old 01-26-2014, 06:39 PM
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I think the point being made here is that raising or lowering back light on a lcd won't have any significant impact on contrast ratio. This is true since both white and black change by the same proportion, so the ratio between white and black stays constant.
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post #36 of 43 Old 01-26-2014, 06:42 PM
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Let's say back light 10 produces 50 fl white and 0.02 fl black. Back light 5 produces 25 fl white and 0.01 fl black.
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post #37 of 43 Old 01-26-2014, 06:55 PM
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which means that the backlight control is multiplicative, not additive.

And Monarch went in with the assumption that it was additive:
Quote:
Originally Posted by MonarchX View Post

On my CCFL TV, using backlight seems to add an equivalent amount of light to my blacks and whites, so my contrast ratio at any backlight setting is almost always the same with a few minor changes.

Learning how controls actually work is kinda important if you're going to be doing experiments and making inferences.
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post #38 of 43 Old 01-26-2014, 07:11 PM - Thread Starter
 
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Spacediver. I pointed out that its from setting to setting, so the word "add" does make sense. Assume Backlight 1 CR = WP/BP. Backlight 2 CR = WP(2)/BP(2), Backlight 3 CR = WP(3)/BP(3). In each case an equal amount (in this case a multiple) must be added to WP and BP to preserve CR. One way or another - other people understood me and you didn't.
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post #39 of 43 Old 01-26-2014, 07:22 PM
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I tend to be a lurker, but I had to add my 2 cents. I thought this forum was to foster education, but we fail to do this when some members don't play nice.


For what it is worth, on my Sharp LED (70inch, 735u) I maximize the white level (contrast adjustment) until clipping and reduce/adjust the backlight to obtain the desired luminance. The black level can interact with this a bit. I use ChromaPure, D3 and i1Pro to calibrate. I have tried the various combinations and permutations (increasing contrast and decreasing backlight) and this progressively increases the measured contrast. In the end, I find the lowest backlight setting, with the highest acceptable contrast setting produces the best viewing picture on my set.

Frank
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post #40 of 43 Old 01-26-2014, 07:24 PM
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seems to be a semantics issue... a 50% increase in white level is met with a 50% increase in black level
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post #41 of 43 Old 01-26-2014, 07:27 PM
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Quote:
Originally Posted by T3b_vat View Post

In the end, I find the lowest backlight setting, with the highest acceptable contrast setting produces the best viewing picture on my set.

I agree
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post #42 of 43 Old 01-26-2014, 07:31 PM - Thread Starter
 
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Originally Posted by Doug Blackburn View Post

You keep demonstrating ignorance in your questions and statements. That's why I try to explain things to you. And, yes, the answers to your question are in what I post, but you're so self-absorbed you can't get past your hatred of my trying to help you get past this awkward stage. Like a 14-year-old who suddenly hates his parents for no good reason. It has been my experience that the best answers I've ever gotten to questions I've asked came from people who provided information... knowledge... and made me think about how that applied to my question. You asked a question without a yes or no answer - a question that required knowledge to understand the issues. If you knew as much as you keep telling us you know, you would not have needed to ask the question in the first place.

Lets just look at your statement quoted above... increase both black level and white level by the same amount provides the same CR...

No, it does not.

a) Black level = 0.03 fL white level = 30 fL CR = 1000:1

b) Black level = 10.03 fL whitel level = 40 fL CR = 3.99:1

All I did in case b was add an equal amount of light to both values, just like you said.. 10 fL added to black and white... which is an equal amount of light. Clearly the contrast ratios are not the same when you add an equal amount of light to black and white

For case b to have a 1000:1 contrast ratio with 40 fL for white, you could only add 0.01 fL to the black level (0.04 fL total). So in this case, as in all cases, the black level has far more influence on contrast than anything else. Just as I posted earlier. There is no universe I know of where 10 fL = 0.01 fL. (Yes, I'm being a smartass and you deserve it in this case).

The real issue here is that you keep thinking you are asking questions with yes or no answers and that's rarely possible when discussing calibration unless you ask something like "Are .3127 and .329 the right xy coordinates for d65?" .

And don't bring the 444 / 422 discussion into this - that whole thread was loaded with people (probably called in by you) to beat down the big bad ogre... who is still correct, by the way. None of your computer video boys could explain or even attempt to explain (or even acknowledge) why a page of colored text originating on a 420 Blu-ray disc looks pristine on a video display (in 422 mode) while a page of colored text from a computer degrades if the computer sends anything but RGB or YCbCr 444 - which was my point all along... 422 is not the problem, if there is a problem, it's coming from something other than 422 color decimation itself - like not doing it right and right includes being able to use 16-240 in Cb and Cr channels rather than being limited to 235 as the luminance channel is). But you (and the other lap dogs you called in) weren't interested in logic or knowledge, only in beating down the only voice of reason in a crap-storm of ignorance and assumptions. And this thread is headed in exactly the same direction.

My wording may have been off, but considering that I reported that CR stays the same at each backlight setting value, it could be easily understood that I get the concept and its the wording that is off - my apologies - you got me there! Other people, though, did understand what I was trying to say.

I am not going to bother explaining 4:2:2 thread. Care to link people to that thread, so they can check out how knowledgeable you are? How your claims that were disproven with actual evidence and how you keep saying that something else somehow is wrong and its not 4:2:2 that is causing it, even though it happens in 4:2:2 mode on just about every TV??? You went as far as saying that if TV performs like people described then there is something wrong with it - that means almost ALL TVs are like that - they ALL got it wrong. You're stuck with your pristine BD point while BD would never display fine text, so you blame PCs and videocards while praising PS3, which uses a videocard just like a PC. I didn't call on any lap dogs, I didn't even start the thread and I did not know any people in it - I pointed you to it and you got butchered by a whole lot of people because they were and still are right. Maybe you should link people to the thread where you claimed that PC videocards get constant firmware updates and drivers that ruin calibrations, even though they almost never get firmware updates and drivers do not ruin calibrations by themselves - settings and profiles do.

Good night because I'm going to sleep tight and I am not going to read another BS reply that points out something you want to pick at to get back at me.
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post #43 of 43 Old 01-26-2014, 07:34 PM - Thread Starter
 
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Quote:
Originally Posted by T3b_vat View Post

I tend to be a lurker, but I had to add my 2 cents. I thought this forum was to foster education, but we fail to do this when some members don't play nice.


For what it is worth, on my Sharp LED (70inch, 735u) I maximize the white level (contrast adjustment) until clipping and reduce/adjust the backlight to obtain the desired luminance. The black level can interact with this a bit. I use ChromaPure, D3 and i1Pro to calibrate. I have tried the various combinations and permutations (increasing contrast and decreasing backlight) and this progressively increases the measured contrast. In the end, I find the lowest backlight setting, with the highest acceptable contrast setting produces the best viewing picture on my set.

Frank

Yes, that is the best way in a dark room environment. In a brighter room, I tend to go with a slightly higher setting. I actually thought that only CCFL screens have this kind of behavior and that LEDs are not affected nearly as much, thus preserving the lowest black level while managing to produce a brighter white point.
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