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Do You See, You Must See, Its A Sammy!

Discussion in 'LCD & LED LCD TVs' started by bonc, Sep 20, 2005.

  1. bonc

    bonc
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    Right guys, im not gonna let this go...

    click on this link

    http://personalcomputing.portrait.com/us/products/lc_lcd_whitepaper.pdf


    (if the link doesnt work ive typed it out for you - http / personalcomputing.portrait.com/us/products/lc lcd whitepaper.pdf)

    I was reading the following article and came across the following pic - go straight to page 9 of this document and look at the picture on the left.

    You will notice the obvious green hue, (my screen is not as obvious as this) but if you notice the peoples faces in the picture - do you see how it looks off colour almost jaundice like!!!

    this is what I notice on my screen, but this seems to only happen on certain lighting conditions not all the time (on faces). X factor (programme)is a good example of where this happens!


    Now do you think this is a calibration issue? i.e RGB levels need to be changed/white levels etc(I have adjusted slightly but still get the problem to some degree)!!!

    or something else?

    Should I get in a a proffesional technicianin in the hopes he can rectify it? or am i being too paranoid, and as this isnt happening on every programme it is something i should accept! (only via my freeview box and screen internal freeview tuner)

    is anyone else noticing this?

    other than this the screen is great, its under warranty but this is driving me mad!!! - I have even seen this on shop floors (samsungs) and am thinking a replacement will only be the same, if not worse!
     
  2. Doctor Hades

    Doctor Hades
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    I can't say I've noticed it on my TV (LE-26R41BD), if it's there that is. What model do you have? Mine is the Freeview (Greenwich) model which has more colour options over the standard one I believe (although I don't know whether that makes a difference or not)...
     
  3. bonc

    bonc
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    Yep freeview Greenich version!

    26 inch screen!
     
  4. bonc

    bonc
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    I am now in the process of getting a replacement!

    will be majorly ****** if this is still the case with the new screen!

    Suprised no one has yet to confirm my findings, Lyris is this what you saw when you sent your screen back?

    Feather brain did you have similar findings?

    anyone else noticed this tendancy for green on this particular samsung LCD?

    All those who dont notice this, I can only assume when you load up your reverse greyscale ramps theres not a hint of green tinge at all (or any other colour for that matter) hmmm.....

    I did read somewhere there samsungs have a tendancy for green push and Sharp a red push - I sure hope not!
     
  5. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Bonc: Found this due to your reponse in another thread. You can find that some shows do not use calibrated camera's or playback systems before broadcast. You can see this regularily on news channels. You'll see person in studio may look quite different from a feed from remote studio or a live in the street feed. It's rare to see it on big shows though. Only way to tell if it's something with the display is to have it loooked at....or replaced as you are having done.

    Gordon
     
  6. bonc

    bonc
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    Thanks Gordon,

    So to clarify, this effect of jaundice in the faces in certain lighting conditons might not be a fault of the panel but as a result of incorrectly broadcast channels!!!

    So are you saying this is a fault of LCD technology?

    And in that case, why is everyone else not noticed this?

    I must admit my new panel is alot better, but I still notice this effect to a lesser degree in certain lighting conditions...

    and if you refer to page 9 (original post)this is as the result of a badly calibrated set with what seems like a slight green push (within the greyscale)!!!!!!

    p.s do LCDS suffer from solirization (is this related) pool of colours round peoples eye sockets, cheeks etc (green,yellowy,browny colour in the samsungs case) degrees of levels differ- dependant on programme/lighting!!!


    p.p.s and would an ISF calibrator be able to remove green push in a set?
     
  7. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    If you can confirm that the colour decoder and the greyscale are correct and then if some material looks weirdly cast then it is either for effect or a broadcast error. There are lots of films or TV series were the use of filters is employed for effect.

    LCD technology can have UNIFORMITY errors. Push the front of your LCD monitor and you'll see the ripples of changing colours coming off it. If the gap between the LCD substrates is not uniform or changes, microscopically, this has an effect on the colour of the image at the point of change. Sets are calibrated at factories so that they have uniform enough capabilities. However it's possible that transit damage or whatever could affect this. The factory calibrations are also not done to perfection degrees as the cost in time would be horrendous. So you may find that if you put up a white field on your LCD display at 100IRE it could look different shades of white at different points of screen. You may find that as you go down in IRE steps to 90/80/50/30 etc the areas of change in colour and in which direction there are errors may change. ie top right might be dimmer than middle and towards green at 90 while bottom left might be purple and dimmer at 40......It's one of the issues with that technology. Most folk do not notice although if it were all corrected you would see the improvement.

    Red Push/Green Push: These are terms thaht are usually attached to how a colour decoder works. Ie the part of the display that works out how many parts of each colour to mix together to overlay on top of the black and white image. To work out where your green error is look at a black and white image....if you dont have one then look at a DVD from the component output of a device and pull out the Pr and Pb leads....now you only have B+W signal going to the screen. If it is obviously green then you have a greyscale error and that part of the panel needs adjustment. To see if you have green error in the colour decoder (which is usually not adjustable....and is extremely rare in my experience) you need to look at test patterns.

    I've not spent enough time with LCD displays to comment on Posterisation affects. LCD's don;t use PWM drive like DLP and plasma so possibly not. I hope to spend some time with Panasonic's new LCD after Scottish HiFi show. Will know more then. No doubt some real techy engineery type guy will come in and explain about causes of Posterisation in LCD......

    Hope this is a little use

    Gordon
     
  8. bonc

    bonc
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    thanks Gordon,

    very helpful..

    right then my old panel or indeed my new screen does not have a green push!

    reason I know this is I have the avia dve disc which has a black and white image with explains if you hacve a colour push the picture would not be completley black and white! - this i found not to be the case and the picture was a perfect black and white on both screens.

    So, i can only put it down to this IRE you mention not being calabirated correctly and a combination of broadcast differences. okay good this has put my mind at rest!

    the only reason i did think my last set and maybe new one may of still had a green push is when I loaded up the reverse grey scales from the avia disc on the lcd screen. this showed a slight tinge in green in dark areas

    however the techy did say this did not consitute a green push and samsung scrrens (i'e the actual screen) may have a slight green hue and nothing to worry about - needless to say i still had it replaced!!

    now, i guess all is left for me to have it properly calibriated - how much do you ISF guys charge? - and playing with the IRE settings do you adjust rRGB settings also?
     

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