I've noticed my TH-50PH9UK exhibits some horizontal banding which seems to be dependent on whether there are contrasting colors near each other. I never see it in video so I never really gave it much thought, but I do notice it with computer images. I don't think it's the source, because I'm using the DVI input which should be entirely digital. The onscreen display also causes a little bit of banding. In the attached image, you can see the slightly different shade of white to the left of the window bar and menu bar.

It's fairly easy to ignore, but just curious if it's normal or if my panel is out of spec.

Do the shaded bands roll up or down the screen? Rolling horizontal shaded bands are a symptom of ground loop which is caused by one or more A/V boxes or inputs into the system being improperly or poorly grounded. if you have a cable TV system, the most common cause appears to be poorly grounded co-axial cable lines. Easily checked by disconnecting the co-axial cable line. A search for ground loop in the archives should turn up multiple threads on ground loops and how to fix it.

Nope, they don't move at all.
Just now I got the bright idea to hook my laptop to my old Panny TH-42PWD7UY via VGA and it exhibits some horizontal banding too under the same conditions, so I guess it's normal.

My 600U does this - the most noticable time is during the green screen before previews. Its pretty annoying. Is there a fix?

My TH50PH8UK does the exact same thing on all inputs - HDMI, Component, S-Video, VGA. Sometimes it is noticeable on program material - e.g. someone sitting in front of a window with horizontal blinds will have lighter toned lines across their face from the contrasting lines of the blinds next to their head. It does not occur on all combinations of contrasting colors, just some. And I have noticed it on at least one 50" consumer model in Bestbuy.

Is it a defect? Probably not, but I have been planning to send Panasonic a photo of it and see what kind of response I get.

my TH-50PH9UK does this as well, it only really happens on the opening previews to movies where it shows the ratings and copywrite warnings so i thought it was my DVD player inputting throught the component BNC. but i recently got the DVI board for computer use and on some web pages the banding is clearly visable.

has anyone had any formal response from panasonic?. FWIW i disconnected all my other inputs, plus the plasma and my CPU are powered from the same uninteruptable power supply so i am confident it is not a ground loop problem.

I suspect it's a power supply issue. The more dark pixels on any given horizontal row of pixels, the brighter the lit pixels appear. It's as if the dark pixels require less power to drive so there ends up being a surplus of power for the light pixels.