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PLEASE HEPL - Screen Door Effect on my Panasonic 36" CRT H..

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December 28, 2004 12:09:33 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Hello,

I have been struggling to find the correct terminology for what I think
I am observing on my recently purchased Panasonic CT-36HL44 TV. I
believe what I am experiencing is "Screen Door Effect". Essentially, I
can see a slight, black grid pattern when I am watching. I realize
that when you are very close to the screen this grid can be seen, but I
also observe it when I am sitting 7+ feet away. I also notice it
during motion with hues (i.e. faces or a grass football field) where it
seems like the picture pauses and goes out of focus ever so slightly
and only momentarily. Also, when there is a large area of lighter
color, I swear I can see the grid across it. I notice this with both
my regular cable (haven't upgraded yet) as well as my progressive scan
DVD. Also, I did the course calibration for the picture in accordance
with "Digital Video Essentials" DVD. My questions...

1. Is this "screen door effect"?
2. Is there anything that can be done to clarify or reduce it?
3. Do all CRTs have this?
4. What about 42" plasmas?
Any advice and input is greatly appreciated. Thanks.

MR
December 28, 2004 7:32:41 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Art

Thanks for the reply? A few clarifying questions.

1. I can see low source quality with the cable, but are you saying the
signal from the DVD is also low enough to cause this?

2. Would you expect the same or better performance relative to this
condition from a plasma?

3. Does this have anything to do with the "black grid" of the screen?
Thanks.

MR
Anonymous
December 28, 2004 8:13:53 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Possible pixilation or artifacting in the picture due to the compression of
the signals. Probably will be visible on other display devices pending on
source quality.
"MR" <guyinmyst2@yahoo.com> wrote in message
news:1104210573.321603.101440@f14g2000cwb.googlegroups.com...
> Hello,
>
> I have been struggling to find the correct terminology for what I think
> I am observing on my recently purchased Panasonic CT-36HL44 TV. I
> believe what I am experiencing is "Screen Door Effect". Essentially, I
> can see a slight, black grid pattern when I am watching. I realize
> that when you are very close to the screen this grid can be seen, but I
> also observe it when I am sitting 7+ feet away. I also notice it
> during motion with hues (i.e. faces or a grass football field) where it
> seems like the picture pauses and goes out of focus ever so slightly
> and only momentarily. Also, when there is a large area of lighter
> color, I swear I can see the grid across it. I notice this with both
> my regular cable (haven't upgraded yet) as well as my progressive scan
> DVD. Also, I did the course calibration for the picture in accordance
> with "Digital Video Essentials" DVD. My questions...
>
> 1. Is this "screen door effect"?
> 2. Is there anything that can be done to clarify or reduce it?
> 3. Do all CRTs have this?
> 4. What about 42" plasmas?
> Any advice and input is greatly appreciated. Thanks.
>
> MR
>
Related resources
Anonymous
December 28, 2004 8:05:16 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

1: Very dependent on how the DVD is connected, the quality of the DVD and
actual information on the DVDs. Pending just how much the video is actually
being compressed. Seen way too many customers hook up a very nice
progressive DVD to composite (yellow, red, white), not even using S-Video,
and complain about pixilation, artifacting, etc.

2: Generally stated: Plasma Display should produce a better reproduction,
again, very dependent on the actual quality of the supplied signals.

3: The Panasonic still has the shadow mask type of CRT in their direct view
sets. Possible in the later, flat CRTS they might be using the aperture
grill type of shadow mask, similar to what SONY has used for quite a while.
Really do not think that will affect the reproduction per your symptom.
Happy New Year to all
"MR" <guyinmyst2@yahoo.com> wrote in message
news:1104237161.127864.94020@z14g2000cwz.googlegroups.com...
> Art
>
> Thanks for the reply? A few clarifying questions.
>
> 1. I can see low source quality with the cable, but are you saying the
> signal from the DVD is also low enough to cause this?
>
> 2. Would you expect the same or better performance relative to this
> condition from a plasma?
>
> 3. Does this have anything to do with the "black grid" of the screen?
> Thanks.
>
> MR
>
Anonymous
December 29, 2004 1:24:44 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

MR wrote:

> I have been struggling to find the correct terminology for what I
> think I am observing on my recently purchased Panasonic CT-36HL44
> TV. I believe what I am experiencing is "Screen Door Effect".
> Essentially, I can see a slight, black grid pattern when I am
> watching. I realize that when you are very close to the screen
> this grid can be seen, but I also observe it when I am sitting 7+
> feet away.

Does this grid become steadily clearer as you get nearer to the screen?
It may be caused by the tube's grid of color spots, and if so then
when you're close enough to make out the individual spots, you'll see
how the spots make up those lines. CRT televisions vary considerably
in how fine that color grid is. My cheap Samsung has a coarse grid,
and it makes a vertical striping pattern that is visible within six
feet. Pricier brands may have a grid that is much much finer, and
quite invisible from three feet. It also helps the grid show a lot
less if it's hexagonal, rather than in vertical columns. If you are in
fact seeing the color-spot grid, then there is no cure except to get a
more expensive TV set.

The motion-related issue is something else entirely, which probably
reflects much more on the quality of signal being sent to you than on
the quality of your TV set.
December 29, 2004 8:10:19 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Thanks to all for the replies - very informative. I am struggling
with a decision on this TV. Seems like the other technology out there
will catch up soon (1-2 years) on standardization, correcting issues
and price. So, struggling with whether to return this set and wait a
few years, or, based on my new understanding, live with the few issues
discussed which aren't that awful for 5-6 years. At any rate, again, I
appreciate the information.

MR
!