Purple Snakes, Magenta Banding on Panasonic Plasmas - Page 4 - AVS Forum
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Old 12-12-2006, 04:51 PM
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Quote:
Originally Posted by TakeFlight View Post

Rarely do I not see this problem at least a few times every time I sit down to watch something on the TV over the course of several hours. Luckily, I'm sitting 11 feet from this TV so most of the time it's not that noticeable. Other than this problem and some more traditional looking false contouring the picture is great on this TV. But, these flaws do creep in from time to time to spoil things.

A properly set up Panasonic does not have these problems.

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Old 12-12-2006, 05:23 PM
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Nobody else finds it significant an LCD with no out of box modifications exhibits the same problem? The screenshots posted in here of the defective sets are identical to what I see. Is there a common term for this that all TV's exhibit? If so, what causes it aside from improper calibration? (In my case, I find it highly suspect calibration can cause sporadic visual anomalies on identical content.)
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Old 12-12-2006, 05:27 PM
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Quote:
Originally Posted by TakeFlight View Post

I too have seen this problem. I have the 42px60u being fed via HDMI from a Comcast/Motorola 6412 DVR. I don't remember the exact screen settings (not in front of the TV right now) but it's somewhere close to this...

Standard Mode
Brightness +7
Contrast +10
Color -4
Tint -6
Sharpness -25
Dark Enhancement: Light
Color Management: On
NR/MPEG etc. are all off

No service menu changes
Latest firmware
Manufactured in Sept. 06

Rarely do I not see this problem at least a few times every time I sit down to watch something on the TV over the course of several hours. Luckily, I'm sitting 11 feet from this TV so most of the time it's not that noticeable. Other than this problem and some more traditional looking false contouring the picture is great on this TV. But, these flaws do creep in from time to time to spoil things.


I have never seen this problem. I am going to take your settings and see if it creates the porblem at home. One quick thing I see I have color management off and firmware 1.21
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Old 12-12-2006, 05:48 PM - Thread Starter
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Elemental,

What do you mean by properly set up? Did you have yours calibrated? Or do you just mean the basic menu settings?

Is yours the 42 inch?
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Old 12-12-2006, 06:03 PM
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Quote:
Originally Posted by SteveK123 View Post

I have never seen this problem. I am going to take your settings and see if it creates the porblem at home. One quick thing I see I have color management off and firmware 1.21


seems like everyone on this thread with problems has the 42" and have their contrast and brightness fairly high

I have the 50" with 1.25 firmware, and have never seen anything like this. My color has been fine. Slightly on the green side, but very good all in all. I haven't seen any type of color banding or colored artifacts

my set has not been calibrated professionally but is adjusted to:

Normal
pic - (10)
bright - (6)
color - 0
tint - (-2)
sharpness -15
black enhancement - light
mgep nr - on
color mgmt - off
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Old 12-12-2006, 06:39 PM - Thread Starter
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Supposedly this doesn't affect the 50 inch. Just the 42 and 37.
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Old 12-12-2006, 06:53 PM
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Here is what I found about this problem:

I tested 5 42PX60U with Harry Potter Goblet of Fire and they were ALL affected by this problem to a certain level. I used cinema mode and tried every input including the HDMI using my PC. Build date were March (2), August (2) and October (1). Firmware version were 1.03, 1.21, 1.25. On the five TV tested only one was showing really big purple snakes but it was still unacceptable on others sets.

I also tested 2 50PX60U and everything was just fine. Gradient were smoother and the picture in general seems better. I finally, exchange my third 42PX60U for a 50PX60U. So far, I haven't noticed any purple snakes effect on the 50.

Hope it can help.
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Old 12-12-2006, 07:10 PM
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I've seen the purple banding before but last night was the first time I noticed the "purple ants." I was watching Letterman's Late Show in HD and it looked as if the edge of his white shirt's cuff was magenta. When he moved it was gone. This caused my attention to peak.

Looking in the background where there's that model cityscape I saw the "purple ants" for the first time. They were all over the cyan-green horizontal sections of the model bridge that permeates the Late Show backdrop. I guess it's supposed to look like oxidized copper or something. Anyway, they're there and anybody (I'm lookin' at you, Elemental1) can use this show as a reference because it comes on a network channel every night.

Of course, the banding and ants change, move, or disappear depending on your picture and brightness settings. I've just passed my 100hr breakin and still have my settings set rather modestly until I can purchase a calibration DVD.

I'm watching the Late Show on cable HD with a DVI->HDMI cable carrying the signal from the STB to the display in cinema mode with Picture set for +5, Brightness set for +6, Tint at -4, and the rest 0 except for sharpness at -10. Black level is set for Light.

Elemental1, you need to tone down the argumentativeness and defensiveness in your posts. It's not simply the users' inability to set up their TVs. Some people are rather educated about electronic displays and home theater and still experience this problem with Panasonic displays. It's no slight against the manufacturer, just an appeal to an esteemed community for support and insight.


edit: ok, Letterman's on right now and the green thing in the backdrop that exhibits the "purple ants" is the model railing/fence on the bridge. Also, they appear in Warm and Normal color temp, but not Cool. So check your color temperature if you can't get them to show up (for testing purposes only, of course).
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Old 12-12-2006, 08:13 PM
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Quote:
Originally Posted by parrspen View Post

Elemental,

What do you mean by properly set up? Did you have yours calibrated? Or do you just mean the basic menu settings?

Is yours the 42 inch?

When I say not set up properly, I am not meaning these people are idiots. It happens and there could also be bad sets since moving assembly to Mexico.
Here is a better shot of Potter and it is easy to see this source film is of low quality. I bet just about any display will have trouble with it to some degree.

This is a 50PX500u and it has had no ISF calibration.
LL

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Old 12-12-2006, 08:55 PM
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New TH-50PX60U owner here. No signs of this issue (yet). Crossing my fingers that it does not appear.
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Old 12-12-2006, 09:25 PM
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Quote:
Originally Posted by cno View Post

seems like everyone on this thread with problems has the 42" and have their contrast and brightness fairly high

I have the 50" with 1.25 firmware, and have never seen anything like this. My color has been fine. Slightly on the green side, but very good all in all. I haven't seen any type of color banding or colored artifacts

my set has not been calibrated professionally but is adjusted to:

Normal
pic - (10)
bright - (6)
color - 0
tint - (-2)
sharpness -15
black enhancement - light
mgep nr - on
color mgmt - off


mines a 42px60u and do not see this issue i even tried takeflights settings and nothing. are people seeing this on sd content or hd content?
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Old 12-12-2006, 11:19 PM - Thread Starter
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We have noticed the problem much more with DVD and XBOX 360. I do see it on SD sometimes, but don't watch much HD programming. Can't Comment on HD-DVD until Christmas ;0)

In my first post I said that the problem does not seem to affect the 50 inchers. It seems like that is still holding true.
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Old 12-13-2006, 12:46 AM
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Quote:
Originally Posted by Odoyle View Post

Looking in the background where there's that model cityscape I saw the "purple ants" for the first time. They were all over the cyan-green horizontal sections of the model bridge that permeates the Late Show backdrop. I guess it's supposed to look like oxidized copper or something. Anyway, they're there and anybody (I'm lookin' at you, Elemental1) can use this show as a reference because it comes on a network channel every night.

Here is Letterman. Please excuse the blurring.
I didn't see any issues, BTW.
LL
LL
LL

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Old 12-13-2006, 03:51 AM
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I think in the UK thread they have already come to the conclusion the 50" versions are free of this problem.
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Old 12-13-2006, 05:11 AM
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Looks like problems with the 42" and 37"! I have this problem on a UK 42PX600. Via internal DTT tuner, XBox360 DVD player and normal Sony DVD player. I have varying viewing distances in my house, from 5ft to 14ft so if get the crap seat, I don't really want to notice it. I have contacted Panasonic UK, and they said they know the problem and are in contact with their engineers or somehting along those lines. Also the Japenese PX60s have the same problem!
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Old 12-13-2006, 05:43 AM
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I have a brand new 37PV60EH (European version with analog tuner). Same problems, also with Xbox 360 connected via VGA.
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Old 12-13-2006, 06:47 AM
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Ah, thanks for the caps, Elemental1. Your third image is the scene I'm talking about. It's hard to tell because of the variety of colorspace conversions from display to camera to display plus exposure variables in the camera, but looks like your colortemp on the display is set to Cool? The "ants" don't show up on my 42" 6U in that colorspace, but they look something like what I drew in the attachment in Normal and Warm. I highlighted the infested area and drew in some simulated ants for effect
LL
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Old 12-13-2006, 08:44 AM
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Quote:
Originally Posted by parrspen View Post

We have noticed the problem much more with DVD and XBOX 360. I do see it on SD sometimes, but don't watch much HD programming. Can't Comment on HD-DVD until Christmas ;0)

In my first post I said that the problem does not seem to affect the 50 inchers. It seems like that is still holding true.


ok I watched a bunch of different content last night dvd SD HD changed settings to takeflights above, and don't see the snakes. mine is a 42" model not a 50" so I'm wondering if its some setting.
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Old 12-13-2006, 09:35 AM
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Quote:
Originally Posted by parrspen View Post

We have noticed the problem much more with DVD and XBOX 360. I do see it on SD sometimes, but don't watch much HD programming. Can't Comment on HD-DVD until Christmas ;0)

In my first post I said that the problem does not seem to affect the 50 inchers. It seems like that is still holding true.

Have you, or any of the others who have witnessed the problems on their sets, observed the problems with OTA HD content. If it shows up on such content that would seem to indicate that it is something that is not been caused by cables or connectivity issues, aside from having the OTA Antenna in play.
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Old 12-13-2006, 09:37 AM
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Quote:
Originally Posted by Odoyle View Post

Ah, thanks for the caps, Elemental1. Your third image is the scene I'm talking about. It's hard to tell because of the variety of colorspace conversions from display to camera to display plus exposure variables in the camera, but looks like your colortemp on the display is set to Cool? The "ants" don't show up on my 42" 6U in that colorspace, but they look something like what I drew in the attachment in Normal and Warm. I highlighted the infested area and drew in some simulated ants for effect

No problem.
The plasma is set to nomal pic mode with warm color temp for TV.
For DvD, it is Cinema and also warm (dark level set to light).
I did not see any issues there in those shots (I did look where you highlighted).
The screenshots really don't show exactly what it looks like.

My HT

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Old 12-13-2006, 09:37 AM
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I hope I can help:
I've got a Panny DLP (Yes, I know, hold your horses..) that was displaying a similar problem, red(purple) banding in low-light, low-contrast scenes. Fog, clouds, indoor lights, etc. The local service guy told me it was "normal" for DLPs.

Obviously, that's a load of BS.

I arranged for an ISF calibration, thinking it could be handled by a color pro, much better than a board-swapping monkey (Factory authorized or not.)

Randy Thomlinson of "The Perfect Vision" came out and tweeked my colors to perfection. However, he noticed the problem as well, and was able to isolate it by displaying a grey ramp with low brightness (sorry for the non-tech description) and it was very obvious: a distinct red tint on one grey bar, and a distinct green tint in another.

It's also possible to reproduce this by turning the "color" adjustment all the way down in scenes with fog, dimly lit skintones, etc. Even with the set displaying "only" B&W, red and green bands will be visible.

It's an all inputs, all resolution, all settings (cinema, normal, etc..) From his $10,000 color generator, and any other source.

Several calls to Panasonic were fruitless.

Recently, a ran across a posting here, from a Panny DLP owner who managed to get his service guy to ADMIT there was a problem, and FIX it. It entailed replacing a board (TNP2AA185S: search on that term here for the history, if you like).

This is a problem with the color decoding, plain and simple. It is fixable (at least on the DLP). Keep after Panny until they address it.


I can't speak to the ants or snakes. I don't have either.

Good luck.

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Old 12-13-2006, 09:46 AM
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Quote:
Originally Posted by spindoctor View Post

This is a problem with the color decoding, plain and simple. It is fixable (at least on the DLP). Keep after Panny until they address it.
I can't speak to the ants or snakes. I don't have either.

Good luck.

It would be ironic if that were the cause since my Panasonic is 8th Gen and actually has a decreased palette and black levels over these new 9th gen panels.

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Old 12-13-2006, 10:00 AM
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A color decoding problem explains why this issue isn't limited to Panny plasmas and I experience it as well. I'm sure nobody cares, but after I talk to the Samsung tech about my problem I'll post the results here.
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Old 12-13-2006, 11:30 AM
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Quote:
Originally Posted by Elemental1 View Post

A properly set up Panasonic does not have these problems.

I could get argumentative over that comment. But, I'll just assume you mean a properly set up Panasonic from the factory. My feeling is, regardless of the display settings, you should never see this display flaw. If you saw this flaw in person, you would understand what I mean. This isn't something that should creep in just because you have the contrast, brightness, tint or color (or whatever) set a certain way. My opinion is that this problem is either fixable via the service menu or it won't be fixable at all (short of a hardware fix).

I have no problems going into the service menu to make a few adjustments if someone comes up with a conclusive fix. But, I'm probably not going to be that person that starts playing around with settings hoping to find a fix.

My dad is getting the 50" model. It will be interesting to compare to my 42" plasma.
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Old 12-13-2006, 11:49 AM
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Quote:
Originally Posted by TakeFlight View Post

I could get argumentative over that comment. But, I'll just assume you mean a properly set up Panasonic from the factory.

If you read the earlier post, there is no need to assume.
Also, I bet your Motorola STB has no option for passthru. It is converting everything.

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Old 12-13-2006, 12:38 PM
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Quote:
Originally Posted by Elemental1 View Post

Also, I bet your Motorola STB has no option for passthru. It is converting everything.

You are correct that there is no way to pass through with the Motorola. However, it is essentially passing through the signal if it's the same as what the box is set to. I have my box set to 1080i. So, it's only converting networks that are 720p (which are few).

However, this (purple snaking, magenta banding) problem has been reported enough times in this thread and others (particularly with the panny 37" and 42") that we are beyond the source being the problem. There's no question the source can exacerbate the problem, but the source isn't causing the problem.
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Old 12-13-2006, 12:41 PM
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Quote:
Originally Posted by Elemental1 View Post

If you read the earlier post, there is no need to assume.

But I'm not sure where you are going with that comment. I can agree with you that a properly configured TV (from the factory) shouldn't exhibit this problem. In fact, you'd be hard-pressed to find someone that does not agree with that. My issue is I'm not sure how that comment is helping. Of course I believe the TV shouldn't have this problem from the factory. But clearly it does. And so clearly it wasn't configured properly from the factory. Hence this forum thread.
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Old 12-13-2006, 01:16 PM
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Quote:
Originally Posted by TakeFlight View Post

But I'm not sure where you are going with that comment. I can agree with you that a properly configured TV (from the factory) shouldn't exhibit this problem. In fact, you'd be hard-pressed to find someone that does not agree with that. My issue is I'm not sure how that comment is helping. Of course I believe the TV shouldn't have this problem from the factory. But clearly it does. And so clearly it wasn't configured properly from the factory. Hence this forum thread.

I am not sure how much some of your posts are helping either.
My response to that particular post of yours was to let owners know that it is not a 'normal' thing and should not be accepted like you were implying.

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In the words of English philosopher Edmund Burke, ÂAll that is necessary for the triumph of evil is that good men do nothing.Â
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Old 12-13-2006, 02:48 PM
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Quote:
Originally Posted by spindoctor View Post

I hope I can help:
I've got a Panny DLP (Yes, I know, hold your horses..) that was displaying a similar problem, red(purple) banding in low-light, low-contrast scenes. Fog, clouds, indoor lights, etc. The local service guy told me it was "normal" for DLPs.

Obviously, that's a load of BS.

I arranged for an ISF calibration, thinking it could be handled by a color pro, much better than a board-swapping monkey (Factory authorized or not.)

Randy Thomlinson of "The Perfect Vision" came out and tweeked my colors to perfection. However, he noticed the problem as well, and was able to isolate it by displaying a grey ramp with low brightness (sorry for the non-tech description) and it was very obvious: a distinct red tint on one grey bar, and a distinct green tint in another.

It's also possible to reproduce this by turning the "color" adjustment all the way down in scenes with fog, dimly lit skintones, etc. Even with the set displaying "only" B&W, red and green bands will be visible.

It's an all inputs, all resolution, all settings (cinema, normal, etc..) From his $10,000 color generator, and any other source.

Several calls to Panasonic were fruitless.

Recently, a ran across a posting here, from a Panny DLP owner who managed to get his service guy to ADMIT there was a problem, and FIX it. It entailed replacing a board (TNP2AA185S: search on that term here for the history, if you like).

This is a problem with the color decoding, plain and simple. It is fixable (at least on the DLP). Keep after Panny until they address it.


I can't speak to the ants or snakes. I don't have either.

Good luck.


What you describe is not a color decoding issue, but a grayscale non-linearity issue. If you were to look at a Grayscale RGB Ratio Plot it would show (based on what you describe) a deviation in the Red and a deviation in the Green making them non-linear. They appear as a bump or dip on the graph/chart that corresponds with the area where the artifact is present in the grayscale. On my set (Tosh DLP), when I had the grayscale calibrated, there was not enough flexibility in the service menu to completely smooth out the grayscale for all three primaries. As a result there was a hump in the red at 40 IRE and a dip in the red at 20 IRE. Aside from that the three primaries were in alignment across all IRE at 100%. This deviation shows itself when viewing some source material where the grayscale transitions through the 40 IRE range and the 20 IRE range. It becomes even more obvious if you use a calibration image such as a gray ramp. There is a colorful banding artifact visible, not coincidentally, where 40 IRE and 20 IRE would fall on the ramp.

It sounds like (just a guess) some of the Panny plasma guys could be describing sets with varied grayscale settings out-of-the-box. If you're lucky, you get one thats pretty dialed in. If you're not, then the person who eye-balled it on the assembly line didn't do a very good job and you get to see the result. My understanding of these sets is that they calibrate well (or at least the older models?) so it may just be a case of getting the grayscale in line to get rid of the artifact it causes.
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Old 12-13-2006, 02:50 PM
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Quote:
Originally Posted by Elemental1 View Post

I am not sure how much some of your posts are helping either.
My response to that particular post of yours was to let owners know that it is not a 'normal' thing and should not be accepted like you were implying.

You seem to be missing the point of this message thread. This isn't a thread singing the praises of all that plasma TVs can be and the blissful owners who are watching these flawless displays. This thread is here to address a specific issue that multiple (dare I say many) people are having with specific Panasonic plasmas. Are you trying to say that each person that posts to this thread saying they are having this problem should put a disclaimer at the end of each message saying that this is not normal behaviour and YMMV? The whole point of the thread is to address a specific issue. I don't feel the need to keep reminding people of that. Why do I need to let owners know this is not a normal thing? Of course it's not normal, that's why this thread exists!!

And I was not implying that anybody should accept this problem. I was simply contributing my experience as well as my screen settings. I wasn't trying to solve the problem with one message post nor tell people to ignore it. When troubleshooting, you never know what information may lead to the solution. Hence, I was offering my own take on the issue and was willing to follow up with whatever other info people needed in hopes of finding a fix to the problem.
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