Purple Snakes, Magenta Banding on Panasonic Plasmas - Page 2 - AVS Forum
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post #31 of 772 Old 12-10-2006, 07:14 PM
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Quote:
Originally Posted by Elemental1 View Post

I am not sure why you are putting up this strawman argument.
The point of my post was clear. If you don't/can't handle hooking up a display and then if there is a question about why it looks the way it looks, don't jump to blaming Panasonic (or whatever brand) for a problem that you have absolutely no clue to the cause of.
It is simply not that hard to verify the set is good or bad.

Because you don't agree with it doesn't make it a strawman argument. I'm telling you it IS hard to verify if a set is good or bad and I was trying to illustrate that point. Because you haven't experienced it does not mean it does not exist. This issue has been pointed out by more and more people lately and is starting to look like a real issue. No one is blaming Panasonic either. We're simply pointing out our experiences in hope that there may be a resolution. I have no idea where you're getting that idea. You don't happen to work for Panasonic, do you? You seem a little touchy. It also has nothing whatsoever to do with being able to hook the display up properly either.
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post #32 of 772 Old 12-10-2006, 07:36 PM
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Quote:
Originally Posted by Bareit View Post

Because you don't agree with it doesn't make it a strawman argument. I'm telling you it IS hard to verify if a set is good or bad and I was trying to illustrate that point. Because you haven't experienced it does not mean it does not exist. This issue has been pointed out by more and more people lately and is starting to look like a real issue. No one is blaming Panasonic either. We're simply pointing out our experiences in hope that there may be a resolution. I have no idea where you're getting that idea. You don't happen to work for Panasonic, do you? You seem a little touchy. It also has nothing whatsoever to do with being able to hook the display up properly either.

You bring up an argument that has no real bearing on my statement. That is a strawman.
Why is it hard to verify that it is a good set?
If you had two sets having this issue then you should already know the odds are that it is NOT the set.
Spare us all the 'this is a possible plasma problem' rants please.
Not blaming Panasonic? What was "I've long passed my 30 day return policy and if this is an issue that Panasonic doesn't acknowledge, what's my recourse?"?
How about doing some actual troubleshooting and before screaming wolf, verify it by swapping out components until you resolve the problem.
If you have a bad set, ok. It's possible.
It doesn't take a rocket scientist to figure that out.

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post #33 of 772 Old 12-10-2006, 07:37 PM
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Do you see any purple ants in these?
LL
LL

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post #34 of 772 Old 12-10-2006, 08:15 PM
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Quote:
Originally Posted by Elemental1 View Post

You bring up an argument that has no real bearing on my statement. That is a strawman.
Why is it hard to verify that it is a good set?
If you had two sets having this issue then you should already know the odds are that it is NOT the set.
Spare us all the 'this is a possible plasma problem' rants please.
Not blaming Panasonic? What was "I've long passed my 30 day return policy and if this is an issue that Panasonic doesn't acknowledge, what's my recourse?"?
How about doing some actual troubleshooting and before screaming wolf, verify it by swapping out components until you resolve the problem.
If you have a bad set, ok. It's possible.
It doesn't take a rocket scientist to figure that out.

You clearly don't know what a straw man argument is. You might read up on it before you use it again.

I've explained why it's hard.

1. Before I purchased my set, I had never heard of this problem before.
2. I returned one set for another and it displayed the same problem.
3. Many people have said they have the same issue.
4. Others have said they do not have this issue.
5. I and others here have said that this appears on ALL inputs and after adjusting picture settings.

With those points, what do we deduce? Is it a problem that happens with some sets and not others? Is it something that happens with all 42" Pannys but some just don't see it(not likely)? If it happens with some, how do we get Panasonic to acknowledge this and either A)replace the set under warranty or B)issue a firmware update that fixes this? Again, no one is blaming Panasonic, we're looking for a solution from them or from each other by discussing it.

My statement, "I've long passed my 30 day return policy and if this is an issue that Panasonic doesn't acknowledge, what's my recourse?", was a what-if. Pay attention to the "if" right before "this is an issue". I don't know if it's an issue Panasonic doesn't acknowledge.

I really don't get your argument as to why this is being discussed and your elitist attitude that this should be an easy thing to figure out.
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post #35 of 772 Old 12-10-2006, 08:16 PM
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snakes on the m@#!f$#@!& plasma!

sorry, couldn't resist.
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post #36 of 772 Old 12-10-2006, 08:18 PM
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Quote:
Originally Posted by Elemental1 View Post

Do you see any purple ants in these?

Two screen caps without much gradient changes in them does not prove anything. Other than show that you don't know anything about the issue that's being discussed here.
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post #37 of 772 Old 12-10-2006, 08:45 PM
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Quote:
Originally Posted by Bareit View Post

Two screen caps without much gradient changes in them does not prove anything. Other than show that you don't know anything about the issue that's being discussed here.

Your last response was just too moronic so I just won't respond beyond this.
Gee....take coax, plug in to RF input. Check pic PQ. Bingo....yeah, that was hard.
Panasonic knows you are full of it just as I do.

Edit: Toned down the b****slap.

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post #38 of 772 Old 12-10-2006, 08:59 PM
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Quote:
Originally Posted by Elemental1 View Post

Your last response was just too moronic so I just won't respond beyond this.
Gee....take coax, plug in to RF input. Check pic PQ. Bingo....yeah, that was hard.
Panasonic knows you are full of it just as I do.

Edit: Toned down the b****slap.

What's moronic about it? Please, enlighten me with your wisdom. All you're doing is attacking people here and not adding anything constructive. I just told you, this is happening on ALL inputs, coax included. It has been checked and confirmed. Now that we know it's not just one input and not just one source, we're trying to figure out if it's something that Panasonic can help with. Why would they think that I or anyone else that's having this problem is "full of it". Are we all tripping on the same acid? Are we all out to get Panasonic? Do you think we all need to just jiggle our HDMI cable a little and the problem will be solved? Your comments are just so out of bounds and so far off the mark it's becoming absurd.
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post #39 of 772 Old 12-10-2006, 09:15 PM
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If you guys want to carry on your digs, could you please take if offline with PMs. The rest of us don't really care what you think of each other but do care that this thread isn't closed because of it.

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post #40 of 772 Old 12-10-2006, 09:26 PM
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Originally Posted by JimP View Post

If you guys want to carry on your digs, could you please take if offline with PMs. The rest of us don't really care what you think of each other but do care that this thread isn't closed because of it.

I regret that this has gone as far as it has but I don't see any reason why this thread would be closed for it.
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post #41 of 772 Old 12-10-2006, 09:30 PM
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Quote:
Originally Posted by flar View Post

OK, I created some ramp images - a gray ramp and an RGB ramp (with 3 separate ramps in R, G, and B stacked on top of each other). I created them as full color 640x480 PNG images to avoid JPEG compression artifacts, but then found that none of my image viewing devices connected to my A/V system could handle PNG (or even GIF) so I did 2 things. First I converted them to JPEG so that I could use A/V components to view them with and second, I connected my 15" Powerbook to the set using a DVI->HDMI cable so I could also view the non-lossy PNG images.

The set I have is a TH-42PX600U.

What I found:

Gray ramp JPEG from Roku looks pretty gray with little coloring - some very slightly magenta bands towards the middle grays.

Gray ramp JPEG from builtin SD card reader - about the same.

Gray ramp PNG from Powerbook - pretty gray.

RGB_ramp JPEG from Roku - some minor variations in the brightness of the 3 color ramps in some localized areas, but nothing major.

RGB_ramp JPEG from builtin SD card reader - a major difference in the green ramp - the greens go dark well before the red and blue. This would definitely cause some magenta bands towards the dark end of a gray ramp, but the gray ramp on the same source didn't show much deviation...?

RGB_ramp PNG from Powerbook - fairly even - like the Roku.

OK now, here's the rub - gray ramp PNG viewed on the Powerbook's LCD display which I generally feel to have very good color - I got lots of greenish and magenta-ish anomalies - almost more than on the plasma display. The same image on my PC's 20" Viewsonic LCD looked pretty accurately gray with almost no perceivable coloration.

The noticeably shorter green ramp that I saw when viewing the image on the set's SD card browser is a perfect example of the kind of mismatched response curves that could cause this magenta issue, but it's odd that the gray ramp on the same source did not show the problem as much as I've seen other places - like when viewing the Dell commercials off of digital cable.

Another possible source of the problem would be the 4:2:2 color sub-sampling in digital video. I would have thought that the JPEG images would have the same color sub-sampling problems, but it could be related to differences in MPEG vs. JPEG decompression software. The times I notice the effect (like on the Dell commercial) are when my Motorola 6412 is doing the MPEG decompression.

Great effort, Thanks!!!

Sounds like green cut in the service menu is set wrong.

Do you have a black and white movie (i.e. Sin City, Casablanca). That should be interesting to watch (magenta, and shades of black and white)

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post #42 of 772 Old 12-10-2006, 09:32 PM
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Originally Posted by Bareit View Post

I regret that this has gone as far as it has but I don't see any reason why this thread would be closed for it.

Moderators do it rather than take the time to delete individual post. They would rather you challange the information, not the person. Helps keeps thing civilized.

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post #43 of 772 Old 12-10-2006, 09:39 PM
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Ok, some constructive ideas:

Do a reset in setup menu or/and unplug from power for at least a few minutes.
Then, from a 'known' good source, check PQ. RF is best since it minimizes components.
If you still have this same issue then:

You don't have a good source.

or

You have a bad plasma set.

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post #44 of 772 Old 12-10-2006, 09:48 PM
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Originally Posted by JimP View Post

Moderators do it rather than take the time to delete individual post. They would rather you challange the information, not the person. Helps keeps thing civilized.

The reason it would be closed is if some certain whiners complained first.

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post #45 of 772 Old 12-10-2006, 09:51 PM
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Quote:
Originally Posted by JimP View Post

Great effort, Thanks!!!

Sounds like green cut in the service menu is set wrong.

Do you have a black and white movie (i.e. Sin City, Casablanca). That should be interesting to watch (magenta, and shades of black and white)

I never noticed the issue with Sin City or Schindler's List and skimming through them now, I don't notice them. Here's something interesting though. One movie that always showed them really well for me was Kiss Kiss, Bang Bang. The scene where Robert Downey Jr is sitting under the counter, in the bathroom, talking to Val Kilmer after he'd peed on the body. On the white wall, under the counter, the purple ants were on full march and changing the picture setting just moved them around the screen. I checked it now and they're gone. Completely. I recently changed some service menu settings which may have affected it.
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post #46 of 772 Old 12-10-2006, 09:54 PM
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Quote:
Originally Posted by Bareit View Post

I recently changed some service menu settings which may have affected it.

You mess with the service menu and then ask why there is a problem?

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post #47 of 772 Old 12-10-2006, 09:55 PM
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Quote:
Originally Posted by Elemental1 View Post

Ok, some constructive ideas:

Do a reset in setup menu or/and unplug from power for at least a few minutes.
Then, from a 'known' good source, check PQ. RF is best since it minimizes components.
If you still have this same issue then:

You don't have a good source.

or

You have a bad plasma set.

I've reset my set many times. I've used my HTPC on HDMI, my DVD on component, my HD cable box on both RF, composite, component, and HDMI, lastly, I've used some test patterns on an SD card and used the SD slot. All with the same results. But...read my previous post. This may have something to do with default service menu settings and not a defective set.
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post #48 of 772 Old 12-10-2006, 09:58 PM
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Quote:
Originally Posted by Bareit View Post

I've reset my set many times. I've used my HTPC on HDMI, my DVD on component, my HD cable box on both RF, composite, component, and HDMI, lastly, I've used some test patterns on an SD card and used the SD slot. All with the same results. But...read my previous post. This may have something to do with default service menu settings and not a defective set.

If you bought two sets that did the same thing and it is so bad, why not go buy a Pioneer for example?
Nobody in their right mind would accept that kind of performance OOTB.

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post #49 of 772 Old 12-10-2006, 09:58 PM
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Quote:
Originally Posted by Elemental1 View Post

You mess with the service menu and then ask why there is a problem?


No, I messed with the service menu AFTER I had the issue. Now it seems like it may have alleviated the issue in some places. I still have them but not in the places they were before. Maybe with some more tweaking they can be eliminated.
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post #50 of 772 Old 12-10-2006, 10:01 PM
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Originally Posted by Bareit View Post

No, I messed with the service menu AFTER I had the issue. Now it seems like it may have alleviated the issue in some places. I still have them but not in the places they were before. Maybe with some more tweaking they can be eliminated.

Did you realize that you can void your warranty by messing with the SM?

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post #51 of 772 Old 12-10-2006, 10:01 PM
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Quote:
Originally Posted by Elemental1 View Post

If you bought two sets that did the same thing and it is so bad, why not go buy a Pioneer for example?
Nobody in their right mind would accept that kind of performance OOTB.


Again with the attacks. Please stop this. The reason I accepted this was because it was an issue that didn't happen all the time. When it did, it was only for a few seconds. Other than that issue, the set was gorgeous, and I thought, for a while, that it may be something all plasmas do. The Pioneer, at the time, was out of my price range and the LG, Hitachi, Samsung, and Toshiba sets didn't look as good to me as the Panny.
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post #52 of 772 Old 12-10-2006, 10:03 PM
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Originally Posted by Elemental1 View Post

Did you realize that you can void your warranty by messing with the SM?

Yes, thanks.
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post #53 of 772 Old 12-10-2006, 10:12 PM
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Quote:
Originally Posted by Bareit View Post

I've reset my set many times. I've used my HTPC on HDMI, my DVD on component, my HD cable box on both RF, composite, component, and HDMI, lastly, I've used some test patterns on an SD card and used the SD slot. All with the same results. But...read my previous post. This may have something to do with default service menu settings and not a defective set.

There was one time when I got my set, I must have fed a bad (out of range possibly) signal through the VGA that had a similar effect. It freaked me out but it wasn't that way OOTB. After resetting the set, all was well. Maybe this is what is happening. I must say that the effect was as if the color pallete was hosed on ALL inputs.

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post #54 of 772 Old 12-10-2006, 10:27 PM
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Looking back at my original SM settings and the new settings, GCUT was not changed. BCUT was left unchanged too. RCUT was changed from 80 to 82, RDRV was changed from EE to F2, GDRV from EF to F2, and BDRV from 97 to 86.
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post #55 of 772 Old 12-10-2006, 11:02 PM
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Quote:
Originally Posted by Elemental1 View Post

There was one time when I got my set, I must have fed a bad (out of range possibly) signal through the VGA that had a similar effect. It freaked me out but it wasn't that way OOTB. After resetting the set, all was well. Maybe this is what is happening. I must say that the effect was as if the color pallete was hosed on ALL inputs.

This effect is much more subtle than that. It only happens under specific conditions - namely the scene has to have a subtle gradient in it and the gradient has to be at particular luminosity levels.

This is not a "plug it in and 'OHMYGOD what the heck is that!'" kind of issue. It's a "one out of 10 or 20 movies might have a scene or two where some will be observant enough to notice it and others might be more absorbed into the plot and miss it" kind of issue. I'm pretty sure that anyone would notice this problem if it occurred and someone pointed to it and said "Look at that". There are several reasons that only some are seeing it:
  • Response curves likely vary from set to set so the degree to which different sets exhibit the problem may vary a lot.
  • The amount of source material that can demonstrate the problem is small and not everyone watches movies prone to show the problem.
  • Not everyone may notice it - I didn't until someone pointed it out.
I'm fairly sure that if the set has some way to tune the response curves of the primary color components individually then this could be easily corrected. I've worked enough in computer graphics and seen problems like this long enough to know that you can adjust your algorithms and/or your gamma adjustment equations to reduce or eliminate problems like this. This isn't so much a "defective set" issue as it is an issue of either "too much variability" or "a poor choice of default values" for the response curves of the sets out of the box.

Bareit has had luck with reducing his problem by playing with the service menus which speaks well for this being a tunable issue. Whether it is something that mere mortals can do or whether it takes an ISF trained technician to get it right remains to be seen.
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post #56 of 772 Old 12-10-2006, 11:07 PM
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Quote:
Originally Posted by Bareit View Post

Looking back at my original SM settings and the new settings, GCUT was not changed. BCUT was left unchanged too. RCUT was changed from 80 to 82, RDRV was changed from EE to F2, GDRV from EF to F2, and BDRV from 97 to 86.

Have you tried looking at my grayscale and RGB ramp images (posted back on page 1 of this thread) and seeing how those are affected by these settings? You can burn them on an SD card and view them with the built in SD card browser...
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post #57 of 772 Old 12-10-2006, 11:58 PM
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Quote:
Originally Posted by flar View Post

This is not a "plug it in and 'OHMYGOD what the heck is that!'" kind of issue. It's a "one out of 10 or 20 movies might have a scene or two where some will be observant enough to notice it and others might be more absorbed into the plot and miss it" kind of issue.

Those screenshots don't look subtle to me.
It is hard with screenshots but that palette is terrible.
I can't find even an SD channel that looks that bad.
Just how many people are complaining about these 'few and far between' problems?
Approx what part of Kong is that shot from (minutes)? I would like to check it out.

Thanks.

Edit: Also, has anybody bothered to not test the cablebox and plug the RF in directly to the set?

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post #58 of 772 Old 12-11-2006, 01:35 AM
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Quote:
Originally Posted by Elemental1 View Post

Those screenshots don't look subtle to me.

They aren't meant to be subtle. They are closeups taken so that the problem becomes obvious. Unfortunately taking a digital photo of a plasma screen from that close up also introduces several other artifacts which make the photos look very ugly and also look like the screen is exhibiting problems that aren't really there in real life.

If you get your eyes within a few inches of a plasma it's not going to look pretty. You'll see the pixels, you'll notice that the plasma tubes flicker a bit because they are being driven by AC signals and by and large the colors will wash out as your eye loses a reference to compare them against. It won't be the pretty image that you are used to viewing from a few feet away.

If you put a digital camera within a few inches of a plasma it will look even uglier. A CCD sensor is not designed for the task at hand and will see not only the problems that your eyeball will notice that close, but others as well due to the nature of the sensor vs. what it is being fed. It will have trouble focusing, the CCD will be experiencing contrasts that are way outside of its intended usage, it won't be able to determine a good white balance, and it will be trying to capture it in a color space that doesn't match the light that is fed to it.

But, while all of those problems make the images look flat, blurry and washed out and make it look like the set has poor PQ, they are anomalies of the way that the images are captured and they are not the problem we are seeing and discussing here. We are talking about the bands of magenta that appear where they shouldn't in those pics.

If you look at the closeup on the forest, the one that looks like a lava lamp of green and yellow - it's ugly and that ugliness is an artifact of the image capture - but even through the ugliness you should only see shades of green and yellow in the ugliness. But instead there are patches of purple mixed in. Where did the purple come from? It came from a mismatch in the response curves of the primary colors.

If you look at the picture of the man standing against the forest background - sure he is out of focus and the colors aren't that great. But if you look off in the forest part of the picture you again see the purple. But at this distance it is harder to make out. Once you see it in the "green and yellow lava lamp" closeup of the forest, it will be easier to spot in that photo too.

Again, behind Kong there is a green patch on the background that should be all green, but has a strange band of purple in it. Sure, the shot on the whole doesn't have very good color, but that is because the lighting conditions weren't conducive to a good digicam shot. Either way, though, the purple hue is just plain out of place no matter what the exposure problems may have been.

Quote:


Edit: Also, has anybody bothered to not test the cablebox and plug the RF in directly to the set?

The magenta/purple patches of color appear regardless of source. It's related to what is in the image, not the quality of the signal. If the signal were improved or degraded then you'd just get a prettier or an uglier picture of the purple bands.

This isn't a "bad signal" problem and it isn't related to the fact that those screenshots, on a whole, look crappy. They are crappy pictures of a very real problem that becomes more subtle as you move away from the set. (Edit: I wanted to reiterate that the "crappiness" comes from the near impossible conditions of the shot, not from a failing of the photographer...)

Look, I work in digital imaging for a living. I've seen these color bands before. They happen when the display device you are using has odd response curves for the primary colors that you didn't notice or that you forgot to take into account when processing the image for display or when you tried to take them into account but got the parameters of the adjustments wrong.
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post #59 of 772 Old 12-11-2006, 03:13 AM
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I found some more test images in another thread:

http://www.avsforum.com/avs-vb/showt...&&#post8969085

With those images viewed from the SD card browser on my 600u they look pretty uniformly gray from my seating position, but if I get closer (2-3 feet) I can see some subtle coloration. On the image where the gray ramp sweeps circularly around the center I can see a slight magenta tinge around the 1:30 position and then an even more subtle tinge around 3:00 and 4:30.

I created a zip file with some resized versions of my gradient images (sized to 1920x1080 so they display full screen with the sets SD card browser) and attached it to this post.

 

TestRamps.zip 32.0927734375k . file
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post #60 of 772 Old 12-11-2006, 05:18 AM
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Quote:
Originally Posted by flar View Post

Have you tried looking at my grayscale and RGB ramp images (posted back on page 1 of this thread) and seeing how those are affected by these settings? You can burn them on an SD card and view them with the built in SD card browser...

Yes, they did not show the purple ants either. I have some other test patterns that displayed the problem before the SM change. I will try them out and report back.
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