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Why are CRT's Better at Non-Native Resolutions?

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Anonymous
January 13, 2005 2:40:32 PM

Archived from groups: rec.video.desktop (More info?)

Why are CRT's better at "non-native" resolutions than LCD's?

The explanation is that CRT's don't have fixed pixel arrays,
but the shadow mask or aperture grill is fixed and so is the
array of phosphors on the CRT. So why is a CRT better?

I got interested in this because I must be the only person
who finds reading text on high-res LCD's difficult. I got
a nice 19" LCD for Christmas but went back to my old
NEC CRT after a few days.

More about : crt native resolutions

Anonymous
January 13, 2005 8:33:01 PM

Archived from groups: rec.video.desktop (More info?)

> Why are CRT's better at "non-native" resolutions than LCD's?

They're analog, so the aliasing is much better than the usual lot of
cheap converter algorithms built into most LCD panels. (continuous beam
wave from the tube vs. ON or OFF on the LCD)

> I got interested in this because I must be the only person
> who finds reading text on high-res LCD's difficult. I got
> a nice 19" LCD for Christmas but went back to my old
> NEC CRT after a few days.

you can easily do it!

1. never run a LCD except at the specified resolution!
2. start->settings-> control panel -> display -> last tab -> advanced
-> adjust the DPI setting up and down to get you a larger font.
3. press or select the AUTO adjust button on the LCD panel.

That's it! On almost all LCD panels made today, that'll give you a
super-tack sharp display with BIG fonts you can read at any distance.

---
Anonymous
January 13, 2005 8:33:15 PM

Archived from groups: rec.video.desktop (More info?)

bluepost22wrote ...
> Why are CRT's better at "non-native" resolutions than LCD's?

Short answer: There essentially is NO "native resolution" on CRTs.

> The explanation is that CRT's don't have fixed pixel arrays,
> but the shadow mask or aperture grill is fixed and so is the
> array of phosphors on the CRT. So why is a CRT better?

1) The RGB triads on a color CRT are MUCH smaller than
the pixels that are beint painted by the electron beams.

2) The RGB triads on a color CRT are "random" and are
not allocated to lines and pixels as they are on LCD or
plasma displays.

This means that you have a wide variety of sweep combinations
that can be painted on a CRT screen without any significant effect
from the actual triad geometry.

On LCD/plasma/LED, etc, the physical pixels are mapped 1:1
with the "native" resolution. Any other resolution requires the
picture to be converted to the "native resolution" and that involves
compromise in image quality, sometimes severe.

> I got interested in this because I must be the only person
> who finds reading text on high-res LCD's difficult. I got
> a nice 19" LCD for Christmas but went back to my old
> NEC CRT after a few days.

You should experiment with font sizes, etc, to optimize for
your selected new resolution before you give up on your
new LCD.
Related resources
Anonymous
January 14, 2005 12:34:19 AM

Archived from groups: rec.video.desktop (More info?)

On a sunny day (13 Jan 2005 11:40:32 -0800) it happened bluepost22@yahoo.com
wrote in <1105645232.941668.277010@z14g2000cwz.googlegroups.com>:

>Why are CRT's better at "non-native" resolutions than LCD's?
>
>The explanation is that CRT's don't have fixed pixel arrays,
>but the shadow mask or aperture grill is fixed and so is the
>array of phosphors on the CRT. So why is a CRT better?
>
>I got interested in this because I must be the only person
>who finds reading text on high-res LCD's difficult. I got
>a nice 19" LCD for Christmas but went back to my old
>NEC CRT after a few days.
>
My Samsung Syncmaster 950 p 19 inch CRT is
352 mm wide, and 264 mm high (real viewing area).
The CRT dot pitch is 0.22 mm hor, and 0.14mm vert.

So that gives (1 / .22 ) * 352 = 1600 pixels hor.
And (1 / .17) * 264 = 1552 pixels vert.

Samsung specifies:
H 1600 dots
V 1200 dots

I think your LCD is not anywhere near it!
Anonymous
January 14, 2005 5:35:17 PM

Archived from groups: rec.video.desktop (More info?)

On a sunny day (Thu, 13 Jan 2005 17:33:15 -0800) it happened "Richard Crowley"
<rcrowley7@xprt.net> wrote in <10ue8asplniq4de@corp.supernews.com>:

>2) The RGB triads on a color CRT are "random" and are
>not allocated to lines and pixels as they are on LCD or
>plasma displays.
Absolutely not.
First there is that Sony trinitron, that has actually vertical lines,
There are specific configurations for the 3 color pixels RGB for different
types of CRT, do a websearch.
The alignment is EXTREMELY regular, certainly not 'random'.

It is interesting, I have been trying to make some artificial holograms
(and then print to DVD as label), I found this software:
http://www.medcosm.com/MedCosm_CGHMaker.html
It is a java program, and should also run in windows.
Make a few diffraction gratings (sort of stripes), and display these
on you monitor.
You will learn about pixels, interference - aliasing- false colors etc..
REALLY QUICK hehe.
The holograms I printed do not meet my expectations.
The idea was to print on CDR, because I found that after using the fixing
spray the patterns I printed with the r200 became translucent (the whole
toplayer), so apart from the usual rainbow colors, the hologram should show
up.
Maybe I need higher resolution still, but ran out of memory on the java
program.
Also it was midnight work..... takes all a lot of time to get the hang of it.
Anonymous
January 14, 2005 9:09:32 PM

Archived from groups: rec.video.desktop (More info?)

> "Richard Crowley" wrote...
> > 2) The RGB triads on a color CRT are "random" and are
> > not allocated to lines and pixels as they are on LCD or
> > plasma displays.

Jan Panteltje wrote...
> Absolutely not.

Bad choice of words. I didn't mean "random" in the sense of
the distribution of stars in the night sky where the spacing
and distribution are uneven.

I meant "random" in the sense of paving stones where there
is a regular pattern, but it is not specifically designed around
the track (wheel spacing) of the vehicles that drive over it.

> First there is that Sony trinitron, that has actually vertical
> lines,

But even there, the triads of RGB stripes is signnificantly
FINER than the spacing of pixels for NTSC or PAL.

Note that there are still some video engineers that prefer to
NOT use a Trinitron picture monitor because the grille
shadow mask artifically enhances the percieved horizontal
resolution. i.e. it makes pictures look like they are in focus
even if they aren't quite focused in real life. Same reason
pro cameras continue to use black&white CRT viewfinders
instead of LCD or plasma. You can actually see the continuous
scan line and more accurately judge critical focus. Your picture
isn't broken up by the pixels in the display.

> There are specific configurations for the 3 color pixels
> RGB for different types of CRT, do a websearch.
> The alignment is EXTREMELY regular, certainly not 'random'.

You are correct. What I meant was that the triads of RGB
emission sites (whether dots, stripes, etc.) is generally
at a much smaller pitch than the pixels of the picture that
is painted on it. As contrasted with LCD/plasma displays
where there is an exact 1:1 correlation between display
pixels and the "native resolution" of the image that the
display is designed for.

> It is interesting, I have been trying to make some artificial
> holograms (and then print to DVD as label), I found this
> software:
> http://www.medcosm.com/MedCosm_CGHMaker.html
> It is a java program, and should also run in windows.
> Make a few diffraction gratings (sort of stripes), and display
> these on you monitor.
> You will learn about pixels, interference - aliasing- false
> colors etc.. REALLY QUICK hehe.

You will note that many LCD displays have an adjustment for the
sampling rate of analog signals so that if the pixel pitch is similar
to the LCD pixel pitch, you can eliminate the moiré pattern caused
by the near-match of image pixels and display pixels. You don't
need such an adjustment on CRT displays becuse the pixel pitch
is so much smaller than any video you are likely to shoot at it.
Anonymous
January 14, 2005 10:04:07 PM

Archived from groups: rec.video.desktop (More info?)

It also helps a lot (with Windows XP) to enable ClearType. For more info
see:
http://grc.com/cleartype.htm

Ule

David Chien <chiendh@uci.edu> wrote in
news:cs77gc$kfh$1@news.service.uci.edu:

>> Why are CRT's better at "non-native" resolutions than LCD's?
>
> They're analog, so the aliasing is much better than the usual lot of
> cheap converter algorithms built into most LCD panels. (continuous beam
> wave from the tube vs. ON or OFF on the LCD)
>
>> I got interested in this because I must be the only person
>> who finds reading text on high-res LCD's difficult. I got
>> a nice 19" LCD for Christmas but went back to my old
>> NEC CRT after a few days.
>
> you can easily do it!
>
> 1. never run a LCD except at the specified resolution!
> 2. start->settings-> control panel -> display -> last tab -> advanced
> -> adjust the DPI setting up and down to get you a larger font.
> 3. press or select the AUTO adjust button on the LCD panel.
>
> That's it! On almost all LCD panels made today, that'll give you a
> super-tack sharp display with BIG fonts you can read at any distance.
>
> ---
>
Anonymous
January 17, 2005 2:10:26 PM

Archived from groups: rec.video.desktop (More info?)

When I search the web on "triad spacing" the result seems
to be that CRT triad pitch is roughly equivalent to today's
pixel pitches. So CRT superiority at non-native
resolutions is due entirely to better analog scanning?

> . . . What I meant was that the triads of RGB
>emission sites (whether dots, stripes, etc.) is generally
>at a much smaller pitch than the pixels of the picture that
>is painted on it. As contrasted with LCD/plasma displays
>where there is an exact 1:1 correlation between display
>pixels and the "native resolution" of the image that the
>display is designed for.
Anonymous
January 17, 2005 2:58:34 PM

Archived from groups: rec.video.desktop (More info?)

bluepos...@yahoo.com wrote:
> When I search the web on "triad spacing" the result seems
> to be that CRT triad pitch is roughly equivalent to today's
> pixel pitches. So CRT superiority at non-native
> resolutions is due entirely to better analog scanning?
I will go out on a theory here, but imagine the bandwidth of the
amplifiers
that drive the CRT to be 'infinite' for a moment.
Now when the electron beam moves over the 'shadow mask' (that is the
screen
with little holes that forces it to land on the right color pixels),
then
NOTHING stops it say from switching on and off in the say 'green hole'
3 times.
So it could theoretically draw 3 green dots in the space of 1.
In reality the bandwidth is set by the pixel clock, and amplifier
rizetime.
But a LCD can never do this!
Again, this is a thery, for BW it is a fact...
What exactly the effect would be on the picture I dunno.
Anonymous
January 17, 2005 10:56:54 PM

Archived from groups: rec.video.desktop (More info?)

On a sunny day (17 Jan 2005 11:10:26 -0800) it happened bluepost22@yahoo.com
wrote in <1105989026.928184.58500@z14g2000cwz.googlegroups.com>:

>When I search the web on "triad spacing" the result seems
>to be that CRT triad pitch is roughly equivalent to today's
>pixel pitches. So CRT superiority at non-native
>resolutions is due entirely to better analog scanning?
I will go out on a theory here, but imagine the bandwidth of the amplifiers
that drive the CRT to be 'infinite' for a moment.
Now when the electron beam moves over the 'shadow mask' (that is the screen
with little holes that forces it to land on the right color pixels), then
NOTHING stops it say from switching on and off in the say 'green hole' 3 times.
So it could theoretically draw 3 green dots in the space of 1.
In reality the bandwidth is set by the pixel clock, and amplifier rizetime.
But a LCD can never do this!
Again, this is a thery, for BW it is a fact...
What exactly the effect would be on the picture I dunno.
Anonymous
January 25, 2005 4:18:39 PM

Archived from groups: rec.video.desktop (More info?)

On 13 Jan 2005 11:40:32 -0800) bluepost22@yahoo.com
wrote in part:
>Why are CRT's better at "non-native" resolutions than LCD's?
>
>The explanation is that CRT's don't have fixed pixel arrays,
>but the shadow mask or aperture grill is fixed and so is the
>array of phosphors on the CRT. So why is a CRT better?
I think it is driver/graphics card problems.
The drivers should be able to map the pixels of one resolution to
the pixels of another resolution with no problem other than
writing the code and the speed of the computer or graphics card.

The mapping happens automatically on CRTs due to the analog nature
of the beam position, so no computational load is added by mapping
pixels from one resolution to another.

I also note that some LCD drivers don't even support the easy mappings
like 960 by 600 on an LCD with 1920 by 1200 native resolution - this
is just laziness.

A projection display using 3 analog tubes with solid phosphors would
be able to beat CRTs and LCD's with no problem
!