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Blacks on Panny 6

Discussion in 'Plasma TVs' started by daveb975, Jan 4, 2004.

  1. daveb975

    daveb975
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    I have recently got the 42" Panny 6, and have got a slight problem with the display of blacks and some other dark colours.

    There appear to be small moving white dots in the black areas.

    This is noticable from my watching distance (about 12 feet), when large areas of black are displayed, but only from close distances when the areas are smaller.

    This happens both on DVD connected via component, and Freeview connected by SCART.

    Has anyone else experienced this?
     
  2. Gordon @ Convergent AV

    Gordon @ Convergent AV
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  3. kaspj

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    ???

    Gordon,

    Can you elaborate - have you seen this on the HD models?

    JP.
     
  4. NeilMcRae

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    Not on my screen.
     
  5. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Not seen enough HD's to say. Every 42" I've come across has dithering pixels in dark parts of image. Theya re not noticeable from viewing location usually. What IRE they appear at varies.

    This is not an artifact that is only Panasonic related. I've seen it on other manufacturers too. I knew it was a can of worms so never bothered mentioning it till now......

    G
     
  6. StooMonster

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    Green flickering dithering dots seen at approximately 50% grey on all inputs on my HD Panny5 50", but tiny percentage IRE either way and they go.

    Rarely seen whilst watching movies or television, seen when using Digital Video Essentials (different luminance grey boxes) and PC display where my desktop colour scheme in Windows XP is grey rather than blue (or if I just change background colour to approximately 50% intensity).

    Gordon's seen it on my screen too.

    StooMonster
     
  7. daveb975

    daveb975
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    Thanks for the advice guys.

    I have been testing mine with some dark film scenes, and it is quite bad.

    I am going to have a play with the settings tonight to try to reduce the effect - I have done one or two things so far, but perhaps I do not have it set up quite correctly.

    Would using a set up DVD like Avia or Video Essentials help with this? Is it likely that this effect varies between panels?
     
  8. FaxFan2002

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    I had the same on my screen - moved the input board and to another socket and it cured it (I suspect a re-seat is in order).

    Rob.
     
  9. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Rob: Could be I suppose but what if you are not using any input module.

    Gordon
     
  10. daveb975

    daveb975
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    Rob - thanks, I will try moving the boards, but I am getting the same effect on both SCART and component.
     
  11. deman77

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    doubt it's the board I get the same on VGA.
     
  12. kaspj

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    Gordon,

    Consider that can of worms well and truly open! Should I be worried (intending to purchase 42HD next month)?

    StooMonster,

    From your post, it doesn't seem particularly an issue, for others it's a problem. Are we all talking about the same condition I wonder?. Could there be other factors at play?.

    JP.:rolleyes:
     
  13. Stumped

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    I have also had this problem on my PWD6 - very noticeable on the cinema mode in the picture menu - switched it over to normal or auto and it went away although i still find skin tones have a slight green tinge to them. I've dropped the contrast and brightness levels and the picture looks fairly healthy from DVD - Sky it tends to vary - need someone to let me know how to adjust the white balance settings in the advanced menu so that i can make skin tones look less green and more realistic.
     
  14. gingerone

    gingerone
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    Out of interest stumped what picture settings did you settle with?
     
  15. Stumped

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    This is just from a quick tweak

    Contrast 11
    bright -3
    Colour -3
    Tint -5
    Sharp 9

    thats on normal with a prog scan input from an Arcam 88 plus. Not happy with it yet but its in most cases very watchable. Just need to address what i see to be a green tinge to skin tones although this is evident on my Tosh 24 inch in the bedroom as well - perhaps its my eyes!
     
  16. FaxFan2002

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    The green dots were really bad on mine, not evident on the VGA input however. Move the component input board and everything was ok.....
     
  17. daveb975

    daveb975
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    I have been checking this out over the last couple of days.

    Blacks themselves seem to be almost 100% unaffected, but it is dark, non-black areas that are.

    Most of the time this is visible from 3-4 feet away, but not my viewing position so it does not matter too much. Sometimes, when there are large areas of dark on the screen this is visible from my viewing position - making that part of the image appear distorted.

    This happens on both the SCART and component inputs. I am wondering if there is a variation in this between units, or whether it is the same on all of them.
     
  18. SimonO

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    I think this is a feature of plasma in general... I've seen it on Pioneers and others...
     
  19. Lone Granger

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    Having seen the Pioneer and Panny at Event2, if the Panny has this sort of problem with the dark blacks it specialises in, then I would be happy to take the somewhat over sharp Pioneer - is there a 'softness' control in the set up that can soften edges a tad on the HD Pionner displays?

    When is the new HD Pioneer 50" due?

    Anyone know any contacts for members attending US CES?
     
  20. jmack

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    i thought these little green dancing pixels helped make the picture detail up.

    i can see them on mine from about 2 ft away , but i sit/lay 9 ft away and cant see them , but if i higher the black to get rid of them i lose detail.
     
  21. Jasonjo

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  22. _Sin

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    I've seen this on every single screen I've looked at (closely). In graphical terms, it's dithering to create the appearance of more colour shades than it can actually produce on a per-pixel basis. It seems to be a property of plasma in general that they just don't do dark. The panasonic is usually acknowledged to be one of the better examples of dealing with that - and I agree (which is why I own one) - but it's still there.

    I couldn't stand the picture on the old pioneer 3 series because of the amount to which it did this, but the new 4 series ones do seem a lot better. However I don't think they've caught up with panasonic yet, thus my preference.

    Also, higher definition displays help - the smaller the pixels the less visible any dithering will be.

    In my humble opinion however, if you can actually see these artefacts when looking at the screen, you're too close! By all means look closely when choosing a screen to see what the picture looks like up close, but ultimately you should probably judge it from a normal viewing distance. I'd never be able to live with the picture quality I can see from 3 inches away, but it's gorgeous from a few feet or more.
     
  23. Jasonjo

    Jasonjo
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    Can someone with the green dots on their Panny 6 please try the solution given a couple of posts above? Interesting to see if the gamma setting does indeed cure/mask this problem???

    Cheers

    JJ
     
  24. jmack

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    i have alot more detail in the darker area`s if my gamma is set to 2.0 if i go to 2.2 its a compromise between detail and blacker dark area`s, and 2.5 gives great black in darker area`s but at a loss of detail.

    i stick to 2.2 gamma.

    i really dont think these green dancing pixels are a problem unless you watch from 2ft away at normal veiwing distanst they help with detail in dark/black area.

    a good sample to try this on is a news reader with a black suit.
    adjust the gamma and see his lapels fade into the black suit background. and if you lower the gamma you see the lapels on his suit better but not as black,

    i dont know what gamma is or does.

    but i do think its a compromise between great blacks and great detail in blacks. outcome is very good blacks with very good detail.

    i will stop rambling now:D :D :D :D
     
  25. Jasonjo

    Jasonjo
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    Cheers jmack
     
  26. _Sin

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    OK, you asked... (sort of). Ignore this post unless you're really bored.

    Gamma gives you more control over how an input signal is translated into actual pixel brightness (along side the usual brightness and contrast controls).

    Brightness is typically mapped as a curve - in other words if the input signal increases linearly, the output brightness follows a curve. The exact shape of the curve is determined by the various picture controls.

    The screen itself can only physically represent a certain range of brightnesses (and thus colours) so the brightness controls let you try to get the best representation for a given application (not all input signals are equal, and the screen itself changes properties over time, otherwise it could probably be factory set).

    The controls work like this:

    Gamma is a curve - the effect is that most of the signal are exagerated, but the darker parts are toned down. This is ok because we usually percieve more detail in lighter parts of a picture and darker bits can be thrown away without you noticing. It's especially important on plasmas because they don't do dark colours very well at all, and you really want the choice of how much of the input signal is left down there and how much to push up into the range of colours that can be reasonably displayed. IIRC the maths involves raising an input signal (considered to be between 0.0 and 1.0) to a power - so a gamma of 1.0 gives a straight line.

    Contrast is a multiplier - it scales the signal up or down so that you can map the input range to the whole range your screen can display (or more or less if you want to exagerate or tone down some aspect of the signal). Think of it as squashing or stretching the curve described above - too much and you end up "clipping" the signal, throwing away bits of the signal at it's limits (kind of like turning the volume up past the capabilities of your speakers). Too little and you don't get any extremes of light and dark and everything starts looking the same.

    Brightness is basically just added or subtracted from the input value - so it makes every pixel brighter or darker, and can be used to "center" the range of input values in the middle of the range your screen can display.

    Obviously some other things can affect how you'd want it set up, such as lighting conditions and such, but on the whole you want black to be black, white to be white, and the shades in between to follow a natural curve.

    I'll shut up now :)
     
  27. jmack

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    cheers for that sin


    so should it be set to 2.0 or 2.5 to get best results
     
  28. _Sin

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    TBH, I couldn't say - I suggest you try each setting out for a while and pick the one which gives the picture *you* like most. (but you might want to alter the brightness and contrast as well if you tweak it).

    I'm still playing around with my settings anyway - I've mostly got my settings quite low at the moment, including gamma. I'll probably change that though, because I'm not entirely happy with the picture now that it's settling in a bit.
     
  29. kaspj

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    Thanks guys. Some very useful info/suggestions.

    JP :)
     
  30. jmack

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    cheers sin

    i`m always adjusting(misses calls it playing) with the settings.

    i got some good settings off stoomonster for plasma and iscan, but was worried about having my contrast at +20,

    now i have all the settings on plasma to 0 and use the iscans picture settings.

    i have found that if i set the gamma to 2.0 it adds a bit of noise to picture.
     

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