I am having a hard time figuring out how to adjust the contrast (aka - "picture") on my Panny plasma (50PH9UK). I'm using DVE, and no matter how high I turn up the contrast, I can still delineate between the 100% and WTW patches.

I've been reading for several days now, and I really do feel as though I'm getting a handle on things. I've used HCFR with GetGray and a Spyder2 colorimeter to calibrate my grayscale, and it's looking pretty good (although I'm still tweaking). But, I can't seem to get a handle on how to properly set contrast on this display. On my previous set it was easy; but it was a RPTV CRT, so I just cranked it up 'till I got blooming, and then pulled it back until it was clean. But these digital dispays... I'm clueless(at least on this issue :D ).

Not all plasma's will let you turn contrast up high enough to make the WTW bars disappear.

Concentrate more on getting brightness right, i.e. absolute black, and a smooth luminance (gamma) curve, and no discolouration at higher levels of white.

You can adjust the WTW bars with the Input Level in the Panasonic Pro models Advanced Settings menu. Keep in mind that your changes may only apply to your DVD source, the level from other devices may be completely different. Also, it may change your gamma slightly.

JD

You can adjust the WTW bars with the Input Level in the Panasonic Pro models Advanced Settings menu. Keep in mind that your changes may only apply to your DVD source, the level from other devices may be completely different. Also, it may change your gamma slightly.

JD

Okay, thanks JD. I'll try using the input level. Does input level only/mainly effect the white level, or does it affect black level as well?

Thanks!
-Guy

It may have a slight affect on BTB, so you should go back and check BTB.

It may have a slight affect on BTB, so you should go back and check BTB.

Thanks, it worked a treat. But now that makes me wonder: how do I know where to set my picture control? I mean, the Input Level allowed me to set my white level properly, but it seems to work independently of the Picture control. In other words, it doesn't seem to matter how bright or dark I set the Picture level, it doesn't change the relationship of 100% white and WTW; only the Input Level seems to affect that, and the Picture level only affects overall brightness. So how do I know what the "proper" setting for the Picture control is? :confused:

Thanks, it worked a treat. But now that makes me wonder: how do I know where to set my picture control? I mean, the Input Level allowed me to set my white level properly, but it seems to work independently of the Picture control. In other words, it doesn't seem to matter how bright or dark I set the Picture level, it doesn't change the relationship of 100% white and WTW; only the Input Level seems to affect that, and the Picture level only affects overall brightness. So how do I know what the "proper" setting for the Picture control is? :confused:

That depends on your viewing environment (dark vs. bright room, etc.). Without using a meter you'll have to go by what is comfortable in your viewing environment.

That depends on your viewing environment (dark vs. bright room, etc.). Without using a meter you'll have to go by what is comfortable in your viewing environment.

Yes, well I do have meters; both a colorimeter and a light meter. So which do I use, and how do I go about setting proper a Picture level? Am I shooting for a specific fL reading on a light meter, or...?

Yes, well I do have meters; both a colorimeter and a light meter. So which do I use, and how do I go about setting proper a Picture level? Am I shooting for a specific FL reading on a light meter, or...?

Using the colorimeter, typically you start out around 100 cd/m^2 for 100% white and adjust from there based on taste and viewing environment. Make sure you use a windowed pattern (not full screen) to avoid the power limiter on the display. Also, when using the spyder2, make sure the probe is as close to the display as possible.

Using the colorimeter, typically you start out around 100 cd/m^2 for 100% white and adjust from there based on taste and viewing environment. Make sure you use a windowed pattern (not full screen) to avoid the power limiter on the display. Also, when using the spyder2, make sure the probe is as close to the display as possible.

Okay, so that translates to 100 lux. Any problem simply using a light meter to measure this?

I'm not really sure how to get that measurement with the Spyder2 in HCFR, which is what I'm using to do calibration measurements. I've only just started using this software package, and there are no english help files, so finding my way around the program is proving to be challenging since I'm new to all of this.

Okay, so that translates to 100 lux. Any problem simply using a light meter to measure this?

I'm not really sure how to get that measurement with the Spyder2 in HCFR, which is what I'm using to do calibration measurements. I've only just started using this software package, and there are no english help files, so finding my way around the program is proving to be challenging since I'm new to all of this.

It's 100 lux/steradian. Just use the S2, the numbers it reports to HCFR are in the correct units (cd/m^2=lux/steradian) as long as the meter is right up next to the display.

It's 100 lux/steradian. Just use the S2, the numbers it reports to HCFR are in the correct units (cd/m^2=lux/steradian) as long as the meter is right up next to the display.

I'm not sre where/how to make this measurement in HCFR. So far I've only figured out how to measure grayscale. I'm still a little fuzzy on the whole contrast/gamma thing in HCFR. Am I simply looking at the 100IRE reading from my grayscale measurement?

Right now they're reading:

R601=107.362
G601=110.905
B601=106.766

I'm not sre where/how to make this measurement in HCFR. So far I've only figured out how to measure grayscale. I'm still a little fuzzy on the whole contrast/gamma thing in HCFR. Am I simply looking at the 100IRE reading from my grayscale measurement?

Right now they're reading:

R601=107.362
G601=110.905
B601=106.766

yes, just change the coordinates in the little window labled "Display" from RGB to xyY and the Y value is the luminance used for contrast/gamma. Also, if you are using an HD input you probably want to change your reference to Rec709 instead Rec601 but that won't effect your grayscale, just the CIE diagram.

Remember, plasmas like CRTs use phosphor that wears over time, so you want to go as LOW as possible while still maintaining an imaage of acceptable brightness.

yes, just change the coordinates in the little window labled "Display" from RGB to xyY and the Y value is the luminance used for contrast/gamma. Also, if you are using an HD input you probably want to change your reference to Rec709 instead Rec601 but that won't effect your grayscale, just the CIE diagram.

Awesome! Thanks. I'm starting to get it.

So right now, my luminance is sitting at 109.794; a little high I guess. So I should turn down the Picture control and take another reading and try and get the Y value to circa 100. Correct?

So far, no HD. But I do know to change to Rec709 for HD sources.

Thanks again!

-Guy

Remember, plasmas like CRTs use phosphor that wears over time, so you want to go as LOW as possible while still maintaining an imaage of acceptable brightness.

Thanks Chris.

I guess I'm just looking to get things as close to reference standard as possible. Is there a standard for this (i.e. - overall light output at 100% white)?

Thanks again.

-Guy

Or a little lower as suggested by Chris. I run my plasma between 95-100.

Hey guys,

One question: when I measure luminance right now after isf calibration, it reads 178 cd. m2. But I'm pretty sure that's about the right setting for contrast on my pio 436.

I've tried to turn it down to about 100 cd. m2. but I believe that's way too low for proper whites. It's about 1/4 of the max contrast capability on the pio.

Do you guys intentionally turn it way down ?.

Dimitri

hi guys

you want to have the contrast as high as possible with out causing the gray scale to shift or whites to clip.

regards

Gregg

If there is colorshifting occurring, would that be only in the higher end of the grayscale?, because my 40 ire window is very reddish for some reason, while the rest tracks pretty good.

Can color shifting occur in the lower regions while the high ones are ok?.

Dimitri

Can color shifting occur in the lower regions while the high ones are ok?.


Yes. This is most noticeable if you look at a continuous ramp signal.

The signal processing is dependant on the values of brightness and contrast and for some combinations there may be zones (IRE values) where the limitations of the processing (algorithm and/or bit depth) create bad effects.

The Panasonic PH series have a fairly unique contrast setup.

The Contrast control is actually a "Drive Contrast" which works like the backlight control on an LCD. If you set it too high you get clipping due to the phosphors being over driven. On the 42" 10 is roughly the maximum but of course this may vary due to other system factors.

The input level control is in fact the "Signal Contrast" that affects the dynamic range of the video signal. Adjust this so that there is no clipping or colour shifting.

This thread on the UK AV Forum has full details of how to work with this panel...

http://www.avforums.com/forums/showthread.php?t=481788

Neil

Contrast on the consumer series 6u Panasonic works the same way, except there is no input level control. Setting the contrast high will only wash out faces and bright scenes. I use my VP50 to drive the input contrast further and set the level properly for each device I have attached. This can also be accomplished by adjusting contrast at the source component.

The picture is stunning using this method.

Thanks Chris.

I guess I'm just looking to get things as close to reference standard as possible. Is there a standard for this (i.e. - overall light output at 100% white)?

Thanks again.

-Guy

Yes, but unless you have a light meter...

He does have a meter, the spyder2 but has gotten conflicting advice from this thread. I recommended shooting for 100 nits and adjusting for taste/environment around that point also keeping in mind phosphor aging as you suggested. Another poster says "maximize contrast" as long as you don't clip or colorshift.

Yes, but unless you have a light meter...

I have both a Spyder2 and a very accurate (photographic) spot meter.

So, what is the standard light level for 100% white (i.e. - 100 IRE)?

Thanks.

-Guy

I have both a Spyder2 and a very accurate (photographic) spot meter.

So, what is the standard light level for 100% white (i.e. - 100 IRE)?

Thanks.

-Guy

Yes, I'd be very interested too....

Dimitri

I believe the SMPTE standard for large venues (theaters) is ~12fL. (~16fL for no film in gate). However, I believe these standards were borne out of what was reasonable and practical given the state of the technology when the standards were adopted. Personally, I’ve met very few displays that I could say is too bright. 12fL strikes me as dim but I can adapt reasonably well to it.

Dave

Edit- From SMPTE...

SMPTE recommends 12–22 fL at the center of the screen with 16 fL as the target and 20% fall-off from center to corner. Most theaters are lucky to reach 6–8 fL, Jones quipped.

Running a plasma @ 16fL would seem to me to negate one of that technologies biggest advantages. (its brightness)

Multiply fL by 3.426259 to get candelas per square meter(nits). Multiply cd/m^2 by 0.29186352 to get fL.

I believe the SMPTE standard for large venues (theaters) is ~12fL. (~16fL for no film in gate). However, I believe these standards were borne out of what was reasonable and practical given the state of the technology when the standards were adopted. Personally, I’ve met very few displays that I could say is too bright. 12fL strikes me as dim but I can adapt reasonably well to it.

Dave

Edit- From SMPTE...

SMPTE recommends 12–22 fL at the center of the screen with 16 fL as the target and 20% fall-off from center to corner. Most theaters are lucky to reach 6–8 fL, Jones quipped.

Running a plasma @ 16fL would seem to me to negate one of that technologies biggest advantages. (its brightness)

Multiply fL by 3.426259 to get candelas per square meter(nits). Multiply cd/m^2 by 0.29186352 to get fL.

The 16fL number may be designed to meet some minimum contrast ratio with minimum screen loading (dark theatre), it does seem awfully low (~55 nits). 100 is a satisfyingly round number to me especially since I'm an SI units kind of guy. ;)

The 16fL number may be designed to meet some minimum contrast ratio with minimum screen loading (dark theatre), it does seem awfully low (~55 nits).I agree. Awfully low. Theaters need to be very dark for good reason. As I noted, I imagine it was set there more out of what was reasonable and practical at the time rather than what was ‘optimal’. It would make little sense to set a commercial spec that couldn’t be reasonably and practically attained given the technology at the time.

I was a projectionist during the era when carbon rods were being replaced by Xenon industry wide. Both the screens I ran took a brightness hit when we transitioned to the Christie Xenon lighthouses. I think that some of the brightest illumination sources (military searchlights, etc) used today are still based on a vaporizing carbon arc. Nasty dirty stuff though.

Dave

But it seems to me that there would/should be some kind of SMPTE (IEC, EBU, NAB, or ???) standard for electronic (i.e. video) displays. I'm thinking about applications such as telecine monitors, broadcast monitors, online editing suites, etc. It would seem unusual for each studio to create their own standard. No?

Well then, there’s this snippet from a brief search… Remarkably close to zoyds 100 nits recommendation.

http://www.kenrockwell.com/apple/30-inch-cinema-display.htm
I use the SMPTE 30 fL standard we use in Hollywood film and TV. This 30 fL peak white value is for video monitors used in dark control rooms. I suggest it for working at night in the dark. Crank it up to your heart's content in the day.
I set my display at one and a half white dots. This is just a tad over the the darkest setting. This measures 30 fL and 6300K with a delta uv of 0.03.
SMPTE 196M "Indoor Theater and Review Room Projection --- Screen Luminance and Viewing Conditions" specifies only 16 fL (55 candelas) for motion picture projection screens.

Dave

Well then, there’s this snippet from a brief search… Remarkably close to zoyds 100 nits recommendation.
Dave

SI units aside, that is basically where I got the rec from, reading about standard broadcast video editing monitors.

http://www.filmlight.ltd.uk/documents/FL-TN-00-002.pdf
:rolleyes:
Condition...........................................Foot-Lamberts........Candelas/sq.m
Scene in bright sunlight.......................................[1500]........ [5000]
Optimum for human eye.........................................[600]........ [2000]
White paper under typical reading light.....................[150]......... [500]
SMTPE video standard white...................................[30].......... [100]
SMTPE cinema standard white.................................[16]......... [55]
Mesopic threshold (rod cells saturating)....................[0.3]......... [1]
Photopic threshold (limit of colour vision)........... .....[0.03]......... [0.1]

The SI unit of illumination is the lux. If we illuminate a white screen with 1 lux, it will have a luminance of 1/π candelas/sq.m. Typical cinema low lighting is about 1 lux. If someone in the audience is wearing white, they will reflect a luminance of about 0.3 candelas/sq.cm. This is less than 1% of the film white.

Edit: that 1/pi

http://www.filmlight.ltd.uk/documents/FL-TN-00-002.pdf
:rolleyes:
Condition...........................................Foot-Lamberts........Candelas/sq.m
Scene in bright sunlight.......................................[1500]........ [5000]
Optimum for human eye.........................................[600]........ [2000]
White paper under typical reading light.....................[150]......... [500]
SMTPE video standard white...................................[30].......... [100]
SMTPE cinema standard white.................................[16]......... [55]
Mesopic threshold (rod cells saturating)....................[0.3]......... [1]
Photopic threshold (limit of colour vision)........... .....[0.03]......... [0.1]

The SI unit of illumination is the lux. If we illuminate a white screen with 1 lux, it will have a luminance of 1/? candelas/sq.m. Typical cinema low lighting is about 1 lux. If someone in the audience is wearing white, they will reflect a luminance of about 0.3 candelas/sq.cm. This is less than 1% of the film white.

Edit: that 1/pi

Excellent. Great document. I will spend some time with it.

The SI unit of illumination is the lux. If we illuminate a white screen with 1 lux, it will have a luminance of 1/? candelas/sq.m. Typical cinema low lighting is about 1 lux. If someone in the audience is wearing white, they will reflect a luminance of about 0.3 candelas/sq.cm. This is less than 1% of the film white.

That is interesting. I calculated the illuminance at the position of an observer 8 feet away from a 100 nits 50" 16x9 display to be ~12 lux. This implies that to recreate the "cinema" experience where the source/background contrast is 55/.3=180, that the room background can't exceed 12/180=.067 lux. This is equivalent to a single candle 12 feet away, that's pretty dark!