[SOWK]

I have a question for all the professional calibrators...


1. How do you set brightness control?


Using the 10 IRE window?


Using a Ramp Pattern?


Using standard pluge pattern?




I have now seen 2 different calibrated setups by 2 very very well know calibrators that set brightness to crush blacks. I am very puzzled by this and looking for an answer as to why this is desired or is this over looked?





Example:



Bring up a 0 - 25 black level ramp pattern.


0 - 16 should be BLACK


17 - 25 Should be shown if the display allows it to be shown.


But on the 2 setups that I saw, they had black level set to where you could not see any black ramp below 20...


You are losing 3 full levels of black, and in some movie scenes a significant amount of shadow detail.







Answers so far:


SOWK - 17 + should be visible

Michael TLV - 17 + should be visible

ChrisWiggles - 17 + should be visible


*anyone or any calibrator that whould have it a different way?

 

[Michael TLV]

Greetings


Pluge pattern ... like on DVE.


there might be reasons for deciding to crush black ... depends on the tV. Had to be done on some poorly designed plasma sets ...


Maybe done to get better gamma response on crappy sets ...


Let's just say that THX and ISF do not advocate this as normal practice. So if the people routinely do this ... they are just doing it to whatever standard they have in their head.


Some calibrators have been known to deviate a lot ... why? because they don't agree with the standards. They feel they know better.


regards

 

[SOWK]



Quote:
Originally Posted by Michael TLV /forum/post/16863097


Greetings


Pluge pattern ... like on DVE.


there might be reasons for deciding to crush black ... depends on the tV. Had to be done on some poorly designed plasma sets ...


Maybe done to get better gamma response on crappy sets ...


Let's just say that THX and ISF do not advocate this as normal practice. So if the people routinely do this ... they are just doing it to whatever standard they have in their head.


Some calibrators have been known to deviate a lot ... why? because they don't agree with the standards. They feel they know better.


regards

These both were on very good Front Projection setups.


One with a Marantz VP-11S2

One with a JVC RS20


Whould you have calibrated to show 17, 18, and 19?


I know I would have.

 

[Michael TLV]

Greetings


Yes to both ...


But would you be dealing with a signal that never had that information in the first place? Many a dvd player with user controls can come out of the box crushing black. Without looking for it, the projector just shows what you give it.


Sometimes people just leave it there ... because they forget to look for what might cause the issues.


regards

 

[ChrisWiggles]

17 visible, basically.


The issue though arises on what pattern was used and how much those levels may be obscured by light spill on a different pattern.


Throw up a pattern with only black bars and a black background and you can discern 17 and up. Throw up black bars on a pattern with a large amount of white, and because of light spill in the system suddenly you can't see a few levels near black.


This conflict requires compromise, and biasing black either higher or lower depending on whether the viewer is more concerned with shadow details, or with absolute black level.

 

[SOWK]



Quote:
Originally Posted by Michael TLV /forum/post/16863572


Greetings


Yes to both ...


But would you be dealing with a signal that never had that information in the first place? Many a dvd player with user controls can come out of the box crushing black. Without looking for it, the projector just shows what you give it.


Sometimes people just leave it there ... because they forget to look for what might cause the issues.


regards

For the RS20 the source device is the Oppo Blu-Ray Player.


I didn't look at the settings inside the Oppo though.


I know most calibrators use external sencore like devices to calibrate.


I was just curious to know what most calibrators would have calibrated to if using a calibration disk and using a ramp pattern to verify results.

 

[SOWK]



Quote:
Originally Posted by ChrisWiggles /forum/post/16863697


17 visible, basically.

Thank you.


I’m also interested in hearing from a calibrator that would purposely calibrate so you can't see 17 18 19 and/or even 20.


Because like I said in the first post, both of the professional calibrations I had seen, only had 20+ visible. These are currently the only 2 real professional calibrated displays I have seen. Every other calibrated display I have seen I have done myself or DIY calibrators.

 

[Michael TLV]

Greetings


Bear in mind that just because you saw someone do it does not mean it is right.


The methodology from both the ISF and THX classes is the same. But it is very possible for someone who took the ISF class to get it wrong ... and to apply that wrong ad infinitum ...


It is the down side of a program that teaches theory and leaves the practice part to be figured out by the attendee at some later date. And if they figure it out wrong ... it stays wrong. Still have the shingle and can still practice professional calibration.


No professional calibrator is supposed to end a calibration based on patterns from a signal generator. If they did ... they were sleeping during class as such a practice is never taught or embraced.


regards

 

[dovercat]

I am not a professional calibrator but I thought the method to calibrate black level - brightness was using a 2% above black bar on a otherwise completely black screen. Setting brightness as low as possible while still being able to see the 2% above black bar. The gamma response of crt is nearly flat near black so there should not be a big difference between black and 2% above black, as digital displays emulate crt. 2% above black is about 20 or 21 digital.

You would then check on test screens with higher average image brightness, on the dve test screen pluge pattern with 20% above black window the 2% above black bar should still be visible. But on the pluge pattern with white bars, only the 4% above black bar on a pluge pattern might be visible and the 2% above black bar might not be at normal viewing distance, although on a dlp projector would be nearer the screen.


With some digital displays you might be able to set black level more precisely at exactly digital 16 = as black as the display will go, which is the ideal. On some dlp projectors it is possible to set digital 16 as exactly black by looking closely at the screen for the point at which dithering stops, the mirrors are off. So with a dlp projector a bar at digital level 17 on a black screen might be visible eyes close to screen as dithering. But being able to distinguish anything below 2% black as distinct from black at normal viewing distance would be dependent on the gamma tracking / contrast ratio of the projector.


Are the pros saying you should be able to see a digital 17 bar on a digital 16 black background at normal viewing distances.

 

[SOWK]



Quote:
Originally Posted by dovercat /forum/post/16864723


Are the pros saying you should be able to see a digital 17 bar on a digital 16 black background at normal viewing distances.

They may not, but I am.


It should be somewhat difficult to see, but yes you should still be able to see it.

 

[tonyptony]



Quote:
Originally Posted by SOWK /forum/post/16863899


Thank you.


I'm also interested in hearing from a calibrator that would purposely calibrate so you can't see 17 18 19 and/or even 20.


Because like I said in the first post, both of the professional calibrations I had seen, only had 20+ visible. These are currently the only 2 real professional calibrated displays I have seen. Every other calibrated display I have seen I have done myself or DIY calibrators.

So as a related question, if you were to go about setting Contrast first at a level that made sense for a given display and setting (for example we know that the 9G Elites with ISF Day can be set for usable output at ~48-50 fL) and then use the 10% .65% method for Brightness (shooting for a Gamma of 2.20), does that jive ultimately with the step pattern method where 17 would then be visible?

 

[SOWK]



Quote:
Originally Posted by tonyptony /forum/post/16864757


So as a related question, if you were to go about setting Contrast first at a level that made sense for a given display and setting (for example we know that the 9G Elites with ISF Day can be set for usable output at ~48-50 fL) and then use the 10% .65% method for Brightness (shooting for a Gamma of 2.20), does that jive ultimately with the step pattern method where 17 would then be visible?

Not always.


I am actually going to ask D-nice if there is a way to get 17 & 18 displayed on the Kuro if you have the correct brightness level setup.


You can see 17 and 18 at proper brightness, only if you have your nose up to the display and look long and hard to see it.


My Kuro doesn't have the ability to show 17 and 18 relatively easy without turning up the brightness control to +2.


This unfortunately raises the absolute black floor to a level I do not want. (aka: I don't want to raise it at all - this lowers not only on/off but ansi as well)


If you have a display that has the capability to show 17 - 18 - 19 without effecting the absolute black you should at least in my opinion, always calibrate it to show those levels.

 

[SOWK]

To mix things up...



I have some reasons as to why some would do this though:


1. Losing the last 1% of shadow detail will allow improperly mastered movies with varying blacks from scene to scene look more uniform. (AKA: not all scenes are authored properly to video level 16 and have a raised black floor.)


2. Increase Gamma


3. Increase 3D effect (partially because of gamma)



*This to me is a personal preference and should not be forced upon the individual paying for calibration.

If paying for a calibration you should stick to the “standards” first. Then show the customer the “benefits” from losing some shadow detail. You need to show the customer some scenes for the added “effects/benifits” and you need to show them a couple of dark scene where the shadow detail is lost. Once done have them decide if losing the shadow detail is worth the difference.

 

[SOWK]

TonypTony:


Here is the PM I sent to D-nice.


Using Pure/ISF DAY/ISF Night



Is there a way to calibrate the display so you can see black level 17 & 18 from normal seating?

Example:



Bringing up a 0 - 25 black level ramp pattern.


0 - 16 should be BLACK


17 - 25 Should be shown.


I can see 17 and 18 at proper brightness (brightness = 0), only if you have my nose up to the display and look long and hard to see it.


My Kuro doesn't have the ability to show 17 and 18 relatively easy without turning up the brightness control to +2.


This unfortunately raises the absolute black floor to a level I do not want. (aka: I don't want to raise it at all - this lowers not only on/off but ansi as well)



-SOWK


***Update***


Removed PM's from D-Nice

 

[D-Nice]

First and foremost,


I do not appreciate you posting our PMs in the Public Section of AVS without first asking me if was ok. They are called Private Messages for a reason.


Since you chose to copy and paste PM information in the public, there is no point in you continuing to PM me about your questions.


Do you know what 17 on the AVS709HD pluge pattern represents? It isn't 0.x% stimuli

If your display needs a +2 brightness level to clearly see 17 on the AVS709HD pluge pattern (which you are using wrong anyway as 17 should be barely visible based on what it truly represents), then that is what it needs. If that is unsatisfactory to you, you will need to play with the gamma and/or G-Low controls.

 

[SOWK]

D-Nice, you are correct, and I apologize for posting the pm's.


If you like I can remove the entire post.


I didn't think there was anything worth hiding in what we were pm'ing.


It was just a quicker way for me to communicate with you.


I will also ask in the future before I post any PM info from you or any member.

 

[SOWK]



Quote:
Originally Posted by D-Nice /forum/post/16865610


If your display needs a +2 brightness level to clearly see 17 on the AVS709HD pluge pattern (which you are using wrong anyway as 17 should be barely visible based on what it truly represents), then that is what it needs. If that is unsatisfactory to you, you will need to play with the gamma and/or G-Low controls.

I don't want to clearly see it as I have mentioned in post 10, but still see it from normal seating distance without squinting at the screen

I did adj gamma with no luck in showing level 17 or 18.


I may try the G-Low control, and see if I can pull the information out.


I personally don't like to touch the Low controls as they work very similar to the brightness control, raising can raise absolute blacks.

 

[D-Nice]



Quote:
Originally Posted by SOWK /forum/post/16865747


I personally don't like to touch the Low controls as they work very similar to the brightness control, raising can raise absolute blacks.

No they don't. Use them improperly and they can tint the lower end of the grayscale... including 0% stimuli... but they don't raise or lower the minimum luminance level.

 

[SOWK]



Quote:
Originally Posted by D-Nice /forum/post/16865879


No they don't. Use them improperly and they can tint the lower end of the grayscale... including 0% stimuli... but they don't raise or lower the minimum luminance level.

The Kuro is very good at not changing luminance levels when changing Bias settings. But it still does ever so small of an amount even if you were to take


Red Low +2

Green Low +2

Blue Low +2


Go beyond +2 and the luminance levels will go up if viewed in a very dark environment.


But on a positive note, running all at +2 provides me enough information to just barley I and I mean just barley see 17 video level.


I have to take a meter to the Kuro to see if I can still get all under 1 de for IRE 10 - 100 with the Bias settings off the default of Zero.


I was able to achieve under 1 de for all IRE levels using just the Gain Settings.


D-Nice - Bias settings on some displays can most defiantly raise brightness.


When I was calibrating my Marantz VP-11S2 and change to Bias also changed the absolute black levels, and I had to readjust the normal brightness control to compensate. (aka I ended up only calibrated using the Gain settings)



BTW: I wanted to thank you for all your work with the Kuro displays.

 

[SOWK]

Back on track...


D-Nice let me get your input on the question above.


When calibrating brightness on a display that "can" show video level 17 - 18 - and 19, without raising absolute black levels, do you calibrate to show these levels? Or do you clip any of the above values?


Any other input from out pro calibrators?




I only have 3 responses so far.