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People shouldn't be expecting fantastic grayscale with their plasmas or LCD's... they've got a way to go before being competitive with CRT in this regards.

No doubt the $10k plasmas do a better job of grayscale. Often an extra boost of brightness will help with grayscale. (at the expense of black being pure black).... It's all a trade-off really.

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Hi Steffche,

I get the same effect on my Pioneer plasma.  But it should only be noticable when you are close to the display.  Do you notice it at the correct viewing distance from the display?

No, not when I'm sitting on my sofa. But when I look at displays in teh shops, they don't seem to look as bad close up. Is your plasma HD?

Yes I have a HD plasma...the Pioneer PDP-43MXE1. But I thought all plasmas (SD & HD) did it.

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Does anyone know what is actually adjusting the greyscale on a plasma?

Is it adjusting the Red Green and Blue levels?

Assuming one knows how to get into the service menu, and has the option to adjust the level of each color, what test pattern could be used in conjunction with the color filter that is supplied with DVE to set them?

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It's a bit hard to explain this one, but hope this helps.

It's about the amount of warmth in the level of black/white between blacker than black and pure white. Very hard to explain in shortened form. I suggest going back over your DVE disk again. Ultimately you can tell you have grayscale issues when faces look sun burned. When this occurs people automatically go for the red/blue/green adjustments but it is in fact a problem with warmth in you grayscale (gradation between pure black and pure white). Another way of picking it up is to look at the graded white to black pattern for any hints of yellowness. Digital displays aren't well known for having a lot of adjustment in their grayscale so explore this at your own risk because if you find that it's not so good the display might not allow you to adjust it out!

This is where it gets tricky because adjusting it out does involve manipulation of the RGB but at a voltage (heat) level rather than at your colour controls. I believe grayscale is a too hot green channel.... but could be wrong on that. If your set is adjusted perfectly to 6500k you should have no grayscale issues or need to adjust.

I'm not sure how you would adjust it out using DVE - those colour adjustments are purely for colour balance at the front end rather than heat adjustment at the back end.

Hope that made sense!

Does anyone know what is actually adjusting the greyscale on a plasma?

Is it adjusting the Red Green and Blue levels?

Assuming one knows how to get into the service menu, and has the option to adjust the level of each color, what test pattern could be used in conjunction with the color filter that is supplied with DVE to set them?

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Does anyone else get fuzzy grey boxes in the grey scale patteren (I think its title 12 chapter 14). A couple of the boxes onm my plasma look like they're fuzzy...not still! Especially noticable when you go to the video demonstration chapters with the red haired model standing next to the test patterns....her jacket is grey, and yet on my plasma it looks like it glowing....slivery...like he pixels can't keep still!

Is this a plasma phenomenon....a plasma setting problem....or are these Philips plasma absolutely %$#@!

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The term “grey scale” is deceptive. What we are really talking about is colour balance.

Put simply, grey scale (or colour balance) is all about getting equal amounts of the three primary colours Red, Green and Blue across the entire luminance range, from black to white.

Black is 0% Red, 0% Green and 0% Blue.

White is nominally, depending on colour temperature 100% Red, 100% Green and 100% Blue or full output from all colours

All the shades of grey in between black and white must also be made up of equal percentages of Red, Green and Blue.

If an unequal amount of the three primary colours is used to produce a shade of grey, a coloured hue will result.

For example, 50% grey should be made up of 50% maximum output from the Red, Green and Blue. If we where to have 60% Red, 50% Green and 50% Blue, a red hue would be introduced into the image, giving peoples faces a reddish look.

A video image is actually made up of two parts. A black and white picture (Luma), and a colour overlay (Chroma) that modifies the black and white image by adding or subtracting various amounts or Red, Green and Blue to give use a colour picture.

To produce an accurate colour picture, a display must be able to produce an accurate black and white picture.

Any coloured hue in the black and white picture will also show up in the colour picture, so we actually use a black and white picture (grey scale ramp) the adjust colour balance.

To get accurate grey scale or colour balance across the full luma range from dark the light, a display needs to be adjusted for accurate grey in shadow, mid tone and highlights.

It is quite common to have highlights correct and shadows way off or visa-versa.

The concept and purpose of grey scale calibration is the same for any display type, but the adjustment systems provided varies.

So to round up, a display with poor grey scale tracking will always have inaccurate colour reproduction.

Colour temperature refers to white point, or what we use as a reference for white.

We need to set a standard for reference white so that video cameras, movie film and various displays can all be calibrated the same.

Colour temperature, measured in degrees Kelvin, can be “Cool” (bluish or 9000K) or “Warm” (redish or 5000K).

The normal white standard is 6500 Kelvin.

The human eye-brain is very good at adapting to changes in colour temperature.

Try wearing a pair of sunglasses with a strong coloured tint.

At first colours will look very strange, but after a short time, your eyes adjust and you don’t notice the strange colour any more until you remove the sunglass.

For this reason, it is imposable to judge colour temperature by eye without a reference.

The only way to adjust the colour temperature or balance of a display is to use a reference monitor, preferably calibrated to 6500K or a test instrument that can directly measure colour temperature.

Even with a reference monitor, adjusting colour balance by eye is almost imposable, especially at the bright, near white end of the scale.

Regards,

Owen

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How much fine adjustment does the average plasma allow?

Do they allow adjustment of R,G,B at different levels (or at all), or just simple colour-temp select? (Should be set to 6503K normally, btw).

{NB: If there is a "tint" control dont use it! (Probably disabled in non-NTSC anyway, but you never know, if the display is 480 lines!)}

The gray scale tracking may be affected by gamma adjustments (if available), as well as "color" (and even brightness and contrast), depending on the quality of the display.

The best picture is achieved in general by carefully getting the combination of

*"temperature" (should normally be ~6503K or "white" - setting higher makes things look "Arctic moonrise", lower makes them "Egyptian sunset");

*sharpness (which should be set so it does nothing to the actual image ... it often just adds false detail and sharpens edges);

*brightness (which affects dynamic range and detail);

*contrast (which can crush detail);

*color (which can make shows look like NCIS!);

*gamma - if available - (see brightness)

correct. You will need to readjust various of the parameters after changing others, so it can take a while, but remember - at least you dont have to converge a plasma!!! :blink:

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How much fine adjustment does the average plasma allow?

Do they allow adjustment of R,G,B at different levels (or at all), or just simple colour-temp select? (Should be set to 6503K normally, btw).

{NB: If there is a "tint" control dont use it! (Probably disabled in non-NTSC anyway, but you never know, if the display is 480 lines!)}

The gray scale tracking may be affected by gamma adjustments (if available), as well as "color" (and even brightness and contrast), depending on the quality of the display.

The best picture is achieved in general by carefully getting the combination of

*"temperature" (should normally be ~6503K or "white" - setting higher makes things look "Arctic moonrise", lower makes them "Egyptian sunset");

*sharpness (which should be set so it does nothing to the actual image ... it often just adds false detail and sharpens edges);

*brightness (which affects dynamic range and detail);

*contrast (which can crush detail);

*color (which can make shows look like NCIS!);

*gamma - if available - (see brightness)

correct. You will need to readjust various of the parameters after changing others, so it can take a while, but remember - at least you dont have to converge a plasma!!!  :blink:

With the NEC plasma you can change all of the above.

Angelo

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Just to add in there that if your player or STB can also affect this. Often they won't pass blacker than black so even if your TV can do it if your source can't then it'll crush them. This is the situation between my marantz dv6400 and HTPC, the Marantz crushes black over component.

So although your display might be able to adjust these things (like black level) it may not be able to improve what you aren't getting and this works in reverse too.

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My Plasma allows (in teh service menu) adjustment of Red Green and Blue in normal color mode. Then there is delta adjustments for the Cool and Warm settings. And thats about it for color greyscale adjustments.

I was hoping that there would be some way of using a test pattern with prehaps the color filters supplied with the DVE disk to adjust the RGB signals.

As for the DVD player not displaying below blacks...I have three DVD players...one Philips one LG and one Pioneer. The LG definitley does not display below black, where as the other two do. The Pioneer has a picture setting between standard, cinema and animation. From what I can see the difference is how much info below black is passed through to the display...with teh standard setting being the best. Cinema is not bad, but blacks are just that...Black, with no definition.

I had a technician come and look at the screen today, and he agreed that it didn't look right, so he will send a report to Philips and hopefully they exchange it...yet again...!

When will this end???

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My Plasma allows (in teh service menu) adjustment of Red Green and Blue in normal color mode. Then there is delta adjustments for the Cool and Warm settings. And thats about it for color greyscale adjustments.

I was hoping that there would be some way of using a test pattern with prehaps the color filters supplied with the DVE disk to adjust the RGB signals.

As for the DVD player not displaying below blacks...I have three DVD players...one Philips one LG and one Pioneer. The LG definitley does not display below black, where as the other two do. The Pioneer has a picture setting between standard, cinema and animation. From what I can see the difference is how much info below black is passed through to the display...with teh standard setting being the best. Cinema is not bad, but blacks are just that...Black, with no definition.

I had a technician come and look at the screen today, and he agreed that it didn't look right, so he will send a report to Philips and hopefully they exchange it...yet again...!

When will this end???

Maybe it's time for me to upgrade the Marantz. It's interesting to see that the new Denons pass below black over component. I mean, if you have a great display that passes below black then your source needs to live up to this expectation! (any excuse to upgrade AGAIN!!!! arghhhhh....)

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The term “grey scale” is deceptive. What we are really talking about is colour balance.

Put simply, grey scale (or colour balance) is all about getting equal amounts of the three primary colours Red, Green and Blue across the entire luminance range, from black to white.

Black is 0% Red, 0% Green and 0% Blue.

White is nominally, depending on colour temperature 100% Red, 100% Green and 100% Blue or full output from all colours

All the shades of grey in between black and white must also be made up of equal percentages of Red, Green and Blue.

If an unequal amount of the three primary colours is used to produce a shade of grey, a coloured hue will result.

For example, 50% grey should be made up of 50% maximum output from the Red, Green and Blue. If we where to have 60% Red, 50% Green and 50% Blue, a red hue would be introduced into the image, giving peoples faces a reddish look.

A video image is actually made up of two parts. A black and white picture (Luma), and a colour overlay (Chroma) that modifies the black and white image by adding or subtracting various amounts or Red, Green and Blue to give use a colour picture.

To produce an accurate colour picture, a display must be able to produce an accurate black and white picture.

Any coloured hue in the black and white picture will also show up in the colour picture, so we actually use a black and white picture (grey scale ramp) the adjust colour balance.

To get accurate grey scale or colour balance across the full luma range from dark the light, a display needs to be adjusted for accurate grey in shadow, mid tone and highlights.

It is quite common to have highlights correct and shadows way off or visa-versa.

The concept and purpose of grey scale calibration is the same for any display type, but the adjustment systems provided varies.

So to round up, a display with poor grey scale tracking will always have inaccurate colour reproduction.

Colour temperature refers to white point, or what we use as a reference for white.

We need to set a standard for reference white so that video cameras, movie film and various displays can all be calibrated the same.

Colour temperature, measured in degrees Kelvin, can be “Cool”  (bluish or 9000K) or “Warm” (redish or 5000K).

The normal white standard is 6500 Kelvin.

The human eye-brain is very good at adapting to changes in colour temperature.

Try wearing a pair of sunglasses with a strong coloured tint.

At first colours will look very strange, but after a short time, your eyes adjust and you don’t notice the strange colour any more until you remove the sunglass.

For this reason, it is imposable to judge colour temperature by eye without a reference.

The only way to adjust the colour temperature or balance of a display is to use a reference monitor, preferably calibrated to 6500K or a test instrument that can directly measure colour temperature.

Even with a reference monitor, adjusting colour balance by eye is almost imposable, especially at the bright, near white end of the scale.

Regards,

Owen

Owen,

Very nice explanation....

A question about the following comment:

To get accurate grey scale or colour balance across the full luma range from dark the light, a display needs to be adjusted for accurate grey in shadow, mid tone and highlights.

It is quite common to have highlights correct and shadows way off or visa-versa.

The concept and purpose of grey scale calibration is the same for any display type, but the adjustment systems provided varies.

Assuming you are familiar with DVE (correct me if I'm wrong?), which pattern in particular do you use to adjust grey-scale? And what sort of adjustment parameters are available on a display such as yours?

Listening and carefully watching the DVE a few times, I got the feeling that calibrating Grey Scale and also Color Temperature is either a subjective task or will require some external equipment. I mean how else can one notice, a touch of yellow in the Grey Scale pattern, as an example.

Could you request some light on calibration of these two aspects in particular?

As a typical example, my plasma allows adjustments of various colours (Red, Blue, Green, Cyan, Magenta, Yellow), and in the Temperature settings there are these things called "Red Amplitude Cutt-off" etc. etc.; which one would correspond with adjusting the Grey Scale? and how what to look for?

thanks,

regards,

Ritesh

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Ritesh,

I do not have DVE, but the test patterns used in DVE are relatively standard so that does not really matter.

I use a HTPC as my source, and use test patterns generated by various software packages I have to calibrate my HD CRT RPTV.

All displays types need similar adjustments.

The normal parameters used to adjust grey scale are:

1. Red Drive, Green Drive and Blue Drive.

( note there are no adjustments for Cyan, Magenta, Yellow as the display only has Red, Green and Blue pixels and all other colours including white and grey, are made up with combinations of RGB)

These adjust the overall gain or drive for the three primary colours and are used to adjust the bright or white end on the scale.

These setting will also affect the middle part or the scale.

2. Red Cut, Green Cut, Blue Cut. (These should be equal to the Amplitude Cut-off settings on your display)

These adjust the shadow or dark part of the grey scale and may also affect the middle part of the scale to some extent.

If you have a menu that includes adjustments for Cyan, Magenta, Yellow, it is most likely for the colour decoder.

The colour decoder is for “decoding” the colour information from a PAL TV signal derived from an analogue tuner, composite or Svideo input but NOT from Component, RGB (VGA) or DVI inputs.

You can test this be checking to see if the controls affect any of these inputs.

If they do, then they can be used to adjust grey scale.

Some displays do have user controls to adjust Red, Blue, Green, Cyan, Magenta, Yellow, but this is not for grey scale adjustment, although you could use them for minor adjustment.

The problem is that they will affect the dark and bright parts of the picture equally.

Colour temperature is quite subjective and IMPOSABLE to calibrate accurately by eye without a reference monitor to compare with, as you eyes-brain will compensate for quite a lot of error.

Colour temperature also affects the dark and bright parts of an image equally, and is NOT related to grey scale.

Grey scale is adjusted with a black and white picture or the “grey scale ramp” test pattern.

There should be no perceptible change in the colour hue of all the grey bars , from black to white.

They should just look grey.

As a final check, a normal video image, with accurate skin tones is useful. Also check for a coloured hue in shadow areas.

This adjustment is near to imposable without a reference monitor for comparison and will never be accurate without test instruments to measure colour.

Regards,

Owen

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