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Calibrating and HD LCD monitor with AJA color bars?

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Michael Pierre
Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 4:55:59 pm

I'm trying to do a couple things.

1. Calibrate my 26" Panasonic HD LCD using color bars either from final cut pro or AJA Control Panel

2. Calibrate my Sony XBR HD CRT (client monitor). I'm sending bars to it from AJA or Final Cut


Is there a trustworthy internet site that can walk me through this process?
Also, I see in the AJA Kona Control Panel where you can choose to send a "Test Pattern", Color Bars %75 or %100 ect....
but I don't see all of the test patterens necessary for calibrating a monitor.
The pattern I'm trying to find is the color bars on top and then the black, white and gray strip below?

Any help or suggestions would be greatly appreciated.


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Bob Zelin
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 6:22:29 pm

Hi -
quick calibration of monitors is as follows. The correct test pattern is SMPTE Color Bars (sometimes refered to as CBS color bars, for the CBS Network reference, that was instrumental in this development, unlike full field bars).

You go to blue only, and adjust your hue or phase adjustment so that all blue (or black and white) areas match in intensity. You adjust your chroma level, so that the thin stripe that seperates the top color bars from the YIQ stuff on the bottom - the colors in the stripe match in intensity - so they look the same.

Get out of blue only, and look at the bars in color. If you turn up the brightness, you will see in the blacks on the lower right, two different levels of black. This is called PLUGE. You adjust your brightness by eye, so you can just barely see the "brighter" black signal, but not enough so that is disappears. This is called "blacker than black" - which you don't want - you dont' want to crush your details in the black.

The Contrast adjustment (which are the white levels) are purely subjective - the old rule was to increase the contrast while looking at the 100% white bar, until the "old CRT" would "smear" - of course, modern CRT's, and of course LCD's don't smear, so you turn it to whatever looks correct to you - this will be the brightest your monitor will get (where you set the contrast).

As far as your "black and white" stuff - FORGET THIS - this was for the old BIAS adjustments in CRT montiors, where you would adjust the RGB in the blacks and whites to make a B+W image look B+W, without any pink or blue hue. You don't do this on a LCD or Plasma, as there are no RGB Bias and GAIN adjustments.

As for your consumer Sony XBR - you are kidding, right ?

bob Zelin


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Michael Pierre
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 8:44:08 pm

No I'm not kidding about the consumer XBR stuff. I think the picture beats the pants off of my 26" "professional" HD LCD.

I know it's not a professional monitor but the picture is INCREDIBLE.
there is also, hue, chroma, brightness and contrast controls that would enable me to adjust the picture to a cbs color bars.

Why couldn't I use a Wratten 47B dark blue photographic filter (for blue only) since the XBR doesn't have that function.

I'm sending the color bars from AJA Kona 3 SDI out to a AJA Hi5 (SDI to HDMI) convertor.

I know this isn't the perfect solution (a Sony BVM would be... but I can't afford that). I'm just trying to get it as calibrated as possible and based on my tests so far it's closer than it was in color reproduction.


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George
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 9:49:06 pm

The Wratten 47B will work with your XBR. The FCP bars have the targets you want.

Here are the instructions again, with illustrations.

http://www.jkor.com/peter/monitor.html

Can you get your XBR to look great? Probably.

Can you get an XBR to be absolutely, certifiably correct? Probably not.

Sony and others make some really expensive specialialized monitors for that. Consumer stuff probably won't reach that last 5% of perfect.

George
Light Images


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Michael Pierre
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 10:52:24 pm

oh yeah, Peter Gray.
ofcourse.
He's good.
thanks.


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walter biscardi
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 11:01:37 pm

[George] "The Wratten 47B will work with your XBR. The FCP bars have the targets you want.

Here are the instructions again, with illustrations."


actually, all of this is also covered very nicely in the Color manual.

Walter Biscardi, Jr.
http://www.biscardicreative.com
HD Editorial & Animation for Broadcast and independent productions.

All Things Apple Podcast! http://cowcast.creativecow.net/all_things_apple/index.html

Read my blog! http://blogs.creativecow.net/WalterBiscardi


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Bob Zelin
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 9:51:37 pm

Michael -
I don't give a CRAP if the picture is "incredible" - we do not look at "incredible" pictures in an edit suite, nor do we listen to "incredible" audio. We look for ACCURATE pictures, and ACCURATE audio. This is why we use near field audio monitors that have a flat response, instead of some "super duper audiophile speakers", whose bass resonse kicks you in the chest. We don't want the colors to jump off the screen, becuase we need to observe ACCURATE COLOR, that will not get rejected, or that will be CONSISTANT at other professional facilities. A Sony consumer TV whose chroma is cranked way up, and whose colors are jumping off the screen (wow, look at the colors, I can get a suntan from that screen), do not reflect an accurate image - no matter how nice the picture looks. We want to see noise, we want to hear hum and hiss issues. We don't want to mask these problems.

The whole point of all this techno mumble jumble is to have STANDARDS, and maintain these standards. When I see some huge subwoffer in an edit room, or mastering suite for audio - well, it's just funny. We actually have to do this for a living, and need to see what other people will see, when the tape leaves your place - and I'm not talking about Grandma, on her Magnavox 42" Plasma.

Bob Zelin


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Michael Pierre
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 10:48:25 pm

Bob you're a crazy guy.

When I need accurate color I rent a BVM series Sony just like I did last week when I Dp'd an HD short. I had to explain/justify the cost of the BVM to the producer who asked why we couldn't use the cheaper 26 inch Panasonic native HD monitor that I own for my edit suite.
My reasons were the same as yours. Accurate Color.

I use the 26" Panasonic in unison with a waveform/vectroscope to get ME close enough (After I've shot the material) before I send the material on to a post house that will bump it up to HD-CAM SR and do the final online edit and color correct.

I do however use my Sony XBR-970 and believe that it's a good enough monitor for a "wow" CLIENT MONITOR. I know "good enough" is subjective.
My question is what's the best way to get my XBR-970 AS ACCURATE AS POSSIBLE.
What about this guy or someone like this?
http://mysite.verizon.net/res8nubd/6500kcalibrations2222222/index.html


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walter biscardi
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 26, 2007 at 10:51:39 pm

[Michael Pierre] "My question is what's the best way to get my XBR-970 AS ACCURATE AS POSSIBLE."

You set it up when you have the BVM in the room. That's what we do here. We have two Sony PVML5 series monitors and once those are calibrated, we match as closely as possible our Panasonic Pro HD Plasma screens. We first set up the bars and then look at the same image on both until they match as closely as possible.

The Plasmas are always slightly more red then the broadcast monitor no matter what we do so we live with that. That's a great monitor for the client to watch but whenever there is a question of accurate color, we always refer back to the Sonys.

Walter Biscardi, Jr.
http://www.biscardicreative.com
HD Editorial & Animation for Broadcast and independent productions.

All Things Apple Podcast! http://cowcast.creativecow.net/all_things_apple/index.html

Read my blog! http://blogs.creativecow.net/WalterBiscardi


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Bob Zelin
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 27, 2007 at 12:29:27 pm

Michael writes -
Bob you're a crazy guy

REPLY -
Michael - I sure try to be !

Bob Zelin




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Michael Pierre
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 27, 2007 at 6:07:20 pm

Love it!


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tony salgado
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 27, 2007 at 6:07:49 pm


Michael,


The most accurate method to calibrate any professional CRT or LCD monitor is to use a monitor probe to set up the gain,bias contrast using established SMPTE monitor alignment specifications (assuming your are doing work in a country which comforms to SMPTE specs).

The SMPTE monitor specs are available as a white paper. Look up SMPTE RP-166, RP-167 etc. A monitor probe looks like a suction cup which attaches to the monitor screen to read the monitor display values. The probe actually has an meter "eye" in it to "sense and see" the display values.


Professional monitors allow adjustments for gain and bias etc whereas consumers monitor will not henceforth why they are not suitable for high end color grading applications.
Gain and bias are the equivalents of white and black balance and allow balancing out the RGB guns so they are all equal. Green is generally used the reference channel and the user will calibrate the Red and Blue channels to Green.

The number one reason why the whites or blacks on one monitor have a blue,red or green color cast when compared to another monitor is that the gain or bias is misadjusted. This will not be solved by setting up color bars to blue check. In fact have you ever noticed why color bars seen to be plus blue or red etc and regardless of what you do to the chroma or hue adjustment you never could quite get bars to look right? Well once again that is a good demonstration of the impact of gain and bias adjustments.


Aligning color bars via blue check is but one small part of properly calibrating a monitor for accurate and consistent color correction grading and/or judging exposure in the field.
Most of the information on the web regarding calibrating a monitor will center on using blue check without regard to the most important calibrations adjustments which are gain,bias,contrast. The reason being blue check is a "common man's" method to quickly set up the monitor and most user's are not using the monitor as a highly accurate grading monitor such as one found in a telecine color correction bay.

In the world we live in today using an inaccurately aligned monitor in the field or even for use with Apple's Color program or other grading system could lead to horrible and painful results if one does not use pre-established monitor reference alignment standards such as the SMPTE RP specs which professional facilities abide by. This is the only real method to allow for a unity reference which several facilities or users can share as a common point of reference and minimize client's concerns about monitors on set or in the edit bay looking different.

A monitor which has not been calibrated with a monitor probe is one which should not be used for serious color grading or as an exposure reference in the field. Such consumer grade monitor are suitable for viewing content NOT GRADING COLOR OR EXPOSURE!! So always advise the viewer or client of this condition or instruct them to use the properly alignment monitor as the reference for critical decisions having to do with exposure,color etc.

I use a CRT monitor probe to calibrate the CRT monitors I use in the field or in the edit suite if I intend to use it as reference monitor. A monitor probe allows matching multiple monitors which makes life a lot easier when a DP desires to have an accurate monitor to look at which also matches the DIT or video controller's engineering monitor.

Contrast adjustments are quite critical given that some LCD monitor such as an Apple cinema display can output such a high foot lambert 100 (FL) level well beyond the SMPTE 30-35 FL specs that you can be fooled into exposing inproperly. The process of judging contrast by eye and memory is not recommend for inexperienced users as their sense of where the contrast level looks right could be quite off compared to the SMPTE spec of 30-35 FL. A monitor probe will measure the FL values and verify once you have reached the proper FL values.

Nailing the proper exposure in the field cannot be done correctly if you have not calibrated contrast and brightness properly henceforth why a monitor probe is a necessary item to truly allow using a monitor as a critical reference guide in addition to a waveform monitor.


Note that for long term repeatability using a monitor probe to calibrate a monitor will always allow consistent results instead of using your memory to wing it by guessing how good the monitor looks from time to time. No one's memory is quite as accurate as an instrument which accurately reads the monitor display values without regard to external distractions. The monitor probe I use has a numerical readout which easily allows hitting specific alignment marks time and time again.

The are a number of different vendors which make monitor probes so I advise doing a google search and get some feedback on which monitor probe suits your application,budget, and requirements.


Tony Salgado


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Bob Zelin
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 28, 2007 at 12:19:29 am

Just remember this, boys and girls. One of the most commonly used monitors in the history of post production - the Sony PVM-20M2U and the Sony PVM-20M4U, came misaligned from the factory (the black bias was misaligned, and all factory new PVM20M2U and M4U looked green in the blacks). Everyone bitched about this, but almost NO ONE ever got the monitor properly recalibrated, and for 10 years, people had a green tint in their blacks - they got used to it. (And this was in NY, for the ultra critical TV commercial market). And now, you want to stick a calibration gun on a consumer Sony XBR. Come on !

We will look back on this 5 years from now, when LCD monitors actually work, and we will say "remember when we actually tried to color correct standard def material on the early LCD monitors".

Bob Zelin


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tony salgado
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 28, 2007 at 12:37:50 am



Bob,

Just to be clear I am not suggesting wasting any time probing a consumer monitor but if you have a lot of time on your hands do whatever you see fit.

FYI everyone when a monitor is turned off the gain and bias will drift. Which is why most high end facilities leave their monitors on all the time for greater stability.

If you don't do this then probing before an important color grading or production shoot session is paramount after the monitor has been allowed to heat up.

My point is if you as the end user are willing to accept and maintain your own quality control standards within established industry guidelines the end outcome will be long term repeatable results in spite of what the folks in NY Bob mentioned are willing to live with.

Must be a East coast thing cause here on the West thing are mighty different. Reminds me of when East Coast and West Coast on line editors had a feud over editing on field one or field two first.


Tony Salgado


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Deadhead
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 29, 2007 at 9:16:02 am

This is a great thread -

Can anyone suggest someone in NYC that can come over and calibrate my 20L5 and 14L5?


Tony are you in NY?



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Sam Zimman
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 29, 2007 at 12:52:51 pm

yeah i got a would also love to hire someone to come over and adjust all our monitors as well.

thanks
-sam


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Wayne Carey
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 29, 2007 at 2:49:54 pm

Hey guys...

Let me ask you this...

How are you getting SMPTE bars thru you Kona card? Are you coming out of FCP?

The reason I ask this is because the Kona card doesn't have SMPTE bars built into it. Go figure. I have every other pattern know to man BUT not SMPTE bars. At the moment, I'm having to use FCP to do this until AJA includes these in their control panel.

_______________________________

Wayne Carey
Schazam Productions
http://www.schazamproductions.com
http://blogs.creativecow.net/waynecarey


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griffisart
Re: Calibrating and HD LCD and SD CRT
on May 29, 2007 at 4:02:50 pm

What kinds of monitor probes are you all using?

Can anyone recommend one that will do LCD and CRT.

We are working with a hand ful of Panasonic BT-LH1700W's and Sony PVM 20M4U and PVM 14L2's.

Any hardware suggestions and / or individuals who provide calibration as a service are greatly appreciated, thanks
Ted


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tony salgado
Re: Calibrating and HD LCD monitor with AJA color bars?
on May 30, 2007 at 4:33:39 am



Hi Deadhead,


No I am not in NY.


My suggestion would be to find a major rental house which has a service department that can take on outside work.

Try Bexel for example.


They have the proper test gear (white and black square pattern generator) and monitor probe to do proper calibration for both HD and SD monitors.


I have my own probe which I use in the field or in post for any CRT or LCD which I intend to do any serious color grading or exposure judgements with.



Tony Salgado


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ronnyron
Re: Calibrating and HD LCD monitor with AJA color bars?
on Jun 1, 2007 at 1:44:38 am

Tony...
U definitely know your stuff!!
Nice working with you in LA earlier this year (G.Garvin).

East Coast/West Coast beef??? Is this video production or 1990's HipHop??
We lost Biggie and Tupac because of that! :)

Hope you're doing well. Nice to see you in the AJA forum.

Ron


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