My 19" LCD packed up the other night, and I thought I'd replace it with a
widescreen (20" or 21") LCD

I've heard good things about the BenQ 20" and about the LG monitors.

Anyone with personal experience with widescreen LCDs? It's going to be used
for graphics, movie watching (a little) and gaming.

I checked Tom's hardware, but all the LCD reviews I could see were last year

Post a reply to this message

"Gail Shaw" wrote:
> I've heard good things about the BenQ 20" and about the LG monitors.

I had a bad experience with an LG monitor, though it wasn't widescreen. I 
can no longer remember its name, but the problems were these two details:

1) The monitor used that technology (I've forgotten the name) where the 
brightness and colors are different depending on which angle you look at the 
monitor from. Most laptop monitors are like this too, but it was very 
uncomfortable for a stationary monitor, especially when working with 
graphics.

2) The monitor was not true 24-bit. Again, I have forgotten what it actually 
was, but it had fewer than 256 colors per channel, which were then 
interpolated. You couldn't see it most of the time, but when working with 
subtle gradient, like a blue sky, it was visible and annoying.

If you find an LG monitor that uses the angle-independent technology and is 
true 24 bit, then these observations don't apply of course.

Rune

Post a reply to this message

Rune escribió:
> 2) The monitor was not true 24-bit. Again, I have forgotten what it actually 
> was, but it had fewer than 256 colors per channel, which were then 
> interpolated. You couldn't see it most of the time, but when working with 
> subtle gradient, like a blue sky, it was visible and annoying.
> 
> If you find an LG monitor that uses the angle-independent technology and is 
> true 24 bit, then these observations don't apply of course.

Wow that sucks. I'm finding 256 colors per channel being not enough! 
(like on grayscale images :P)

Post a reply to this message

Nicolas Alvarez wrote:

> Wow that sucks. I'm finding 256 colors per channel being not enough! 
> (like on grayscale images :P)

That's... interesting. I'm fairly sure I read somewhere that for 
*greyscale* the human visual system can only distinguish about 16 
different levels. (Not sure whether that's *linear* though...)

Post a reply to this message

Orchid XP v7 escribió:
> Nicolas Alvarez wrote:
> 
>> Wow that sucks. I'm finding 256 colors per channel being not enough! 
>> (like on grayscale images :P)
> 
> That's... interesting. I'm fairly sure I read somewhere that for 
> *greyscale* the human visual system can only distinguish about 16 
> different levels. (Not sure whether that's *linear* though...)

Yeah, if I have 16 *consecutive* grayscale values (185, 186, 187, 188, 
189...) on an image, I can definitely distinguish them!

Post a reply to this message

Orchid XP v7 <voi### [at] devnull> wrote:
> That's... interesting. I'm fairly sure I read somewhere that for 
> *greyscale* the human visual system can only distinguish about 16 
> different levels.

  That's unusually easy to prove wrong. How many bars can you count in
this image? http://warp.povusers.org/images/grayscales.png

  The number you counted is the amount of grayscales you can distinguish
at least. (The true number is probably at least that times 10 or more.)

-- 
                                                          - Warp

Post a reply to this message

"Warp" wrote:
> Orchid XP v7 <voi### [at] devnull> wrote:
>> That's... interesting. I'm fairly sure I read somewhere that for
>> *greyscale* the human visual system can only distinguish about 16
>> different levels.
>
>  That's unusually easy to prove wrong. How many bars can you count in
> this image? http://warp.povusers.org/images/grayscales.png
>
>  The number you counted is the amount of grayscales you can distinguish
> at least. (The true number is probably at least that times 10 or more.)

While some cells in the eye may be able to distinguish that many colors, 
that doesn't mean that the visual system in the brain can. A lot of 
preprocessing is done in the eyes themselves before the visual data is sent 
to the brain.

For example, the eyes have an edge detecting layer I think, or something 
along those lines. This layer could find all the edges of the bars in your 
image and send information about these edges on to the brain, so that the 
brain can tell how many bars there are. The eyes also send the actual "raw" 
brightness info on to the brain, but this may be in a "low resolution" where 
no more than 16 different shades can be told apart. However, the brain can 
still count all the bars, becuase of the edges detected in the eyes.

I'm not saying it's like that; just that your image doesn't prove anything 
about the amount of gray scales the brain can tell apart. So it really comes 
down to what you mean by "human visual system" - the eyes or the brain.

Rune

Post a reply to this message

Warp escribió:
> Orchid XP v7 <voi### [at] devnull> wrote:
>> That's... interesting. I'm fairly sure I read somewhere that for 
>> *greyscale* the human visual system can only distinguish about 16 
>> different levels.
> 
>   That's unusually easy to prove wrong. How many bars can you count in
> this image? http://warp.povusers.org/images/grayscales.png
> 
>   The number you counted is the amount of grayscales you can distinguish
> at least. (The true number is probably at least that times 10 or more.)
> 
First two and last two look quite similar from some angles (damned LCD 
screen). Also, the black ones look all similar (damned gamma; the world 
would be a better place if screens had had built-in gamma correction 
since the beginning).

Post a reply to this message

Rune <aut### [at] runevisioncom> wrote:
> For example, the eyes have an edge detecting layer I think, or something 
> along those lines. This layer could find all the edges of the bars in your 
> image and send information about these edges on to the brain, so that the 
> brain can tell how many bars there are. The eyes also send the actual "raw" 
> brightness info on to the brain, but this may be in a "low resolution" where 
> no more than 16 different shades can be told apart. However, the brain can 
> still count all the bars, becuase of the edges detected in the eyes.

  I'm quite certain that if it was an animation where each frame is
completely filled by a shade of gray and was played eg. at 1 FPS, you
could clearly see the change.

-- 
                                                          - Warp

Post a reply to this message

Warp nous apporta ses lumieres en ce 2007/11/17 12:19:
> Orchid XP v7 <voi### [at] devnull> wrote:
>> That's... interesting. I'm fairly sure I read somewhere that for 
>> *greyscale* the human visual system can only distinguish about 16 
>> different levels.
> 
>   That's unusually easy to prove wrong. How many bars can you count in
> this image? http://warp.povusers.org/images/grayscales.png
> 
>   The number you counted is the amount of grayscales you can distinguish
> at least. (The true number is probably at least that times 10 or more.)
> 
I can count about 30 very distinct bands, monitor permiting.

-- 
Alain
-------------------------------------------------
A short cut is the longest distance between two points.

Post a reply to this message

"Warp" <war### [at] tagpovrayorg> wrote in message 
news:473f3242@news.povray.org...
> Rune <aut### [at] runevisioncom> wrote:
>> For example, the eyes have an edge detecting layer I think, or something
>> along those lines. This layer could find all the edges of the bars in 
>> your
>> image and send information about these edges on to the brain, so that the
>> brain can tell how many bars there are. The eyes also send the actual 
>> "raw"
>> brightness info on to the brain, but this may be in a "low resolution" 
>> where
>> no more than 16 different shades can be told apart. However, the brain 
>> can
>> still count all the bars, becuase of the edges detected in the eyes.
>
>  I'm quite certain that if it was an animation where each frame is
> completely filled by a shade of gray and was played eg. at 1 FPS, you
> could clearly see the change.

That might be one test, but it still makes it easy for the brain by showing 
transitions.

What if you had a test that didn't allow the eyes/brain to calibrate from 
frame to frame?

What if your vision was blanked for a time (eg. half-second or second) 
between each successive frame?  How many grey shades could you distinguish 
reliably?

Post a reply to this message

Brian Elliott escribió:
> What if your vision was blanked for a time (eg. half-second or second) 
> between each successive frame?  How many grey shades could you 
> distinguish reliably?

That wouldn't be a fair test. It's hard for humans to find differences 
between two images (even big differences) if the image blanks for a 
second before showing the other. I saw an example that swapped two 
images with a black screen in between, then did it again without the 
black screen and *then% I could notice the differences.

Anyway, I don't care about an accurate test of eye sensitivity. I just 
know that I can notice "color bands" on grayscale images, and more bits 
per channel would avoid that.

Post a reply to this message

Nicolas Alvarez escribió:
> I just know that I can notice "color bands" on grayscale images, and
> more bits per channel would avoid that.

Oh, and I remember a suggestion of converting a 48-bit image to 24-bit 
using dithering. I wonder how good that would look...

Post a reply to this message

Rune wrote:
> A lot of 
> preprocessing is done in the eyes themselves before the visual data is sent 
> to the brain.

You'd be amazed. :-)

> For example, the eyes have an edge detecting layer I think, or something 
> along those lines.

First a change detector layer, then from that a bunch of edge detectors, 
then object detectors, then motion detection, then ...

Before it leaves you're eyes, they already know there's something large 
coming towards you from the left. That info is hooked directly from eyes 
to neck muscles.

> This layer could find all the edges of the bars in your 
> image and send information about these edges on to the brain, so that the 
> brain can tell how many bars there are. 

True.

> The eyes also send the actual "raw" 
> brightness info on to the brain, but this may be in a "low resolution" where 
> no more than 16 different shades can be told apart. 

Well, it's an analog pulse train. Actually, I'm not sure how far up the 
pile before *you* decide it's no longer eyes and has become brain. I'm 
also not sure if the cells that actually sense light are integrated into 
anything at a higher level at all, or whether all their info is 
processed before getting to the "brain" part.

> However, the brain can 
> still count all the bars, becuase of the edges detected in the eyes.

> I'm not saying it's like that; just that your image doesn't prove anything 
> about the amount of gray scales the brain can tell apart. So it really comes 
> down to what you mean by "human visual system" - the eyes or the brain.

I think if you're picking out a monitor, you're worried about your 
brain's perception of it. :-)

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

Post a reply to this message

Nicolas Alvarez nous apporta ses lumieres en ce 2007/11/17 19:12:
> Nicolas Alvarez escribió:
>> I just know that I can notice "color bands" on grayscale images, and
>> more bits per channel would avoid that.
> 
> Oh, and I remember a suggestion of converting a 48-bit image to 24-bit 
> using dithering. I wonder how good that would look...
It can look very good, if the resolution is fine enough. The best would be to 
use something like "error diffusion" dithering. That's a random noise dithering 
technique. That's the way I got the best printing for smooth shades.

-- 
Alain
-------------------------------------------------
One tequila, two tequila, three tequila, floor.

Post a reply to this message

Darren New nous apporta ses lumieres en ce 2007/11/17 19:45:
> Rune wrote:
>> A lot of preprocessing is done in the eyes themselves before the 
>> visual data is sent to the brain.
> 
> You'd be amazed. :-)
> 
>> For example, the eyes have an edge detecting layer I think, or 
>> something along those lines.
> 
> First a change detector layer, then from that a bunch of edge detectors, 
> then object detectors, then motion detection, then ...
> 
> Before it leaves you're eyes, they already know there's something large 
> coming towards you from the left. That info is hooked directly from eyes 
> to neck muscles.
> 
>> This layer could find all the edges of the bars in your image and send 
>> information about these edges on to the brain, so that the brain can 
>> tell how many bars there are. 
> 
> True.
> 
>> The eyes also send the actual "raw" brightness info on to the brain, 
>> but this may be in a "low resolution" where no more than 16 different 
>> shades can be told apart. 
> 
> Well, it's an analog pulse train. Actually, I'm not sure how far up the 
> pile before *you* decide it's no longer eyes and has become brain. I'm 
> also not sure if the cells that actually sense light are integrated into 
> anything at a higher level at all, or whether all their info is 
> processed before getting to the "brain" part.
> 
>> However, the brain can still count all the bars, becuase of the edges 
>> detected in the eyes.
> 
>> I'm not saying it's like that; just that your image doesn't prove 
>> anything about the amount of gray scales the brain can tell apart. So 
>> it really comes down to what you mean by "human visual system" - the 
>> eyes or the brain.
> 
> I think if you're picking out a monitor, you're worried about your 
> brain's perception of it. :-)
> 
Processing steps for human vision:
- retina catch light
- Raw image processing by the retina itself
- More image processing between the retina and the optical nerve
- Still more processing by the optical nerve (maybe the only nerve that have 
actual processing capability)
- Final gross processing by the brain
- Pattern recognition and image reconstruction
- Visual memory cross references image completion
I may have missed/myss ordered some steps...

-- 
Alain
-------------------------------------------------
There will always be beer cans rolling on the floor of your car when the boss 
asks for a ride home from the office.

Post a reply to this message

Nicolas Alvarez wrote:

> First two and last two look quite similar from some angles (damned LCD 
> screen). Also, the black ones look all similar (damned gamma; the world 
> would be a better place if screens had had built-in gamma correction 
> since the beginning).

Wow... Having a color corrected screen does wonders. I can see all 32 
levels. I can also see I need to run the calibration tool on my CRT 
again (the lower 2 levels don't show, but they do on the LCD)

I've seen these grayscales used on photography sites occasionally to 
make sure brightness and contrast are optimal.

Post a reply to this message

Gail Shaw wrote:
> My 19" LCD packed up the other night, and I thought I'd replace it with a
> widescreen (20" or 21") LCD

My home monitor is a Samsung 22" widescreen (Can't remember the exact 
model number off-hand) The only drawback is if you get far enough 
off-axis the colors begin to distort, but it has good contrast ratio, 
and very fast response time.

One of my primary complaints about the monitor I have at work is if you 
scroll white text over a black background, it literally disappears. 
Doesn't happen on my Samsung.

Ah, here it is, the 226BW:

http://tinyurl.com/24544j

Post a reply to this message

And lo on Sun, 18 Nov 2007 00:10:30 -0000, Nicolas Alvarez  
<nic### [at] gmailisthebestcom> did spake, saying:

> Brian Elliott escribió:
>> What if your vision was blanked for a time (eg. half-second or second)  
>> between each successive frame?  How many grey shades could you  
>> distinguish reliably?
>
> That wouldn't be a fair test. It's hard for humans to find differences  
> between two images (even big differences) if the image blanks for a  
> second before showing the other. I saw an example that swapped two  
> images with a black screen in between, then did it again without the  
> black screen and *then% I could notice the differences.

Look up saccadic masking, our eyes blank out info when they're moving so  
you could have two screens with no intermission if they just in different  
places relative to a neutral background.

-- 
Phil Cook

--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com

Post a reply to this message

> Look up saccadic masking, our eyes blank out info when they're moving so 
> you could have two screens with no intermission if they just in different 
> places relative to a neutral background.

You mean like the attached images?  Which pair of squares are the same 
colour and which pair are different?  (I used colours from Warp's vertical 
bar image)

Post a reply to this message

Attachments:
Download 'grey test.png' (3 KB) Download 'grey test 2.png' (3 KB)

Preview of image 'grey test.png'

Preview of image 'grey test 2.png'

"Gail Shaw" <initialsurname@sentech sa dot com> wrote:
> My 19" LCD packed up the other night, and I thought I'd replace it with a
> widescreen (20" or 21") LCD
>
> I've heard good things about the BenQ 20" and about the LG monitors.
>
> Anyone with personal experience with widescreen LCDs? It's going to be used
> for graphics, movie watching (a little) and gaming.
>
> I checked Tom's hardware, but all the LCD reviews I could see were last year

My wife’s PC has a BenQ monitor. It is not a wide screen but the image quality
is quite good (acceptable to me) and it was quite cheap. But I found out later
that they use “slave labour”. Well under paid immigrant labout.

Stephen

Post a reply to this message

And lo on Mon, 19 Nov 2007 15:28:26 -0000, scott <sco### [at] laptopcom> did  
spake, saying:

>> Look up saccadic masking, our eyes blank out info when they're moving so
>> you could have two screens with no intermission if they just in  
>> different
>> places relative to a neutral background.
>
> You mean like the attached images?  Which pair of squares are the same
> colour and which pair are different?  (I used colours from Warp's  
> vertical
> bar image)

I was thinking more top-left, top-left plus bottom-right, bottom-right,  
reverse; so your eye would move from one to the other but not be able to  
have both colours up at the same time for any comparison. No transition  
flicker, no edge detection, just were those two colours the same.

-- 
Phil Cook

--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com

Post a reply to this message

Mike Raiford escribió:
> Nicolas Alvarez wrote:
> 
>> First two and last two look quite similar from some angles (damned LCD 
>> screen). Also, the black ones look all similar (damned gamma; the 
>> world would be a better place if screens had had built-in gamma 
>> correction since the beginning).
> 
> Wow... Having a color corrected screen does wonders. I can see all 32 
> levels. I can also see I need to run the calibration tool on my CRT 
> again (the lower 2 levels don't show, but they do on the LCD)
> 
> I've seen these grayscales used on photography sites occasionally to 
> make sure brightness and contrast are optimal.

The problem is that if your screen is perfectly color-corrected, 
everything looks weird, because the people who design websites, etc. 
work with non-color-corrected screens!

Post a reply to this message

"Gail Shaw" <initialsurname@sentech sa dot com> wrote:
> My 19" LCD packed up the other night, and I thought I'd replace it with a
> widescreen (20" or 21") LCD
>
> I've heard good things about the BenQ 20" and about the LG monitors.
>
> Anyone with personal experience with widescreen LCDs? It's going to be used
> for graphics, movie watching (a little) and gaming.
>
> I checked Tom's hardware, but all the LCD reviews I could see were last year

I have a  Hewlett Packard  "HP w20"

For graphics/rendering/3D-Modeling, videos/animations, DVD's the monitor is OK
For Office and development a wide-monitor is IMO generally better than
a 4:3-monitor.


"Gaming" - I can't say very much to this, because I'm using LINUX.


The monitor does have two horrible (and IMO absolutly useless)
integrated speakers. But this is not a specific problem of *this* monitor
the most integrated monitor-speakers  sounds terrible.
So I don't use them.

My conclusion:

I love this wide-monitor and never want back to a 4:3-monitor

Post a reply to this message

Nicolas Alvarez wrote:
> The problem is that if your screen is perfectly color-corrected, 
> everything looks weird, because the people who design websites, etc. 
> work with non-color-corrected screens!

I still keep Gamma at 2.2, since Windows apps are usually designed to 
that, and most websites created on the PC are designed to that. The D65 
whitepoint takes some getting used to, for a while everything looks too 
yellow, but colors look richer.

In an ideal world, people would use an image editor that has color 
management (Photoshop) and web browsers would have proper color 
management, which would eliminate the gamma and color issues. But using 
a proper color-managed workflow is tricky, especially when working with 
multiple outputs.

Post a reply to this message

"Meothuru" <nomail@nomail> wrote in message
news:web.47427b6b1d7416445a73e3b40@news.povray.org...
> My conclusion:
>
> I love this wide-monitor and never want back to a 4:3-monitor
>

I fell in love with the widescreen when I bought a 17" laptop. It's heavy,
but so nice to work on.

Post a reply to this message

"Mike Raiford" <mra### [at] hotmailcom> wrote in message
news:47418ced$1@news.povray.org...
> Gail Shaw wrote:
> > My 19" LCD packed up the other night, and I thought I'd replace it with
a
> > widescreen (20" or 21") LCD
>
> My home monitor is a Samsung 22" widescreen (Can't remember the exact
> model number off-hand) The only drawback is if you get far enough
> off-axis the colors begin to distort, but it has good contrast ratio,
> and very fast response time.

Not sure if there's space on the desk for a 22". The 20 is going to take
some squeezing. Will look at it.

Post a reply to this message

Gail Shaw wrote:

> Not sure if there's space on the desk for a 22". The 20 is going to take
> some squeezing. Will look at it.

Measure first. :) I originally had a 19" CRT that seemed to take up a 
lot of space on the desk, the 22" took up a little more space, but still 
  fit. if 20 or 21 is a squeeze, I'd definitely check dimensions before 
I purchased the screen.

Post a reply to this message

"Gail Shaw" <initialsurname@sentech sa dot com> wrote:
> I've heard good things about the BenQ 20" and about the LG monitors.


I recently bought an LG monitor, a 24" widescreen L246W and I'm pretty
happy with it. The type of panel is important if you're doing art with POV-Ray,
or anything that requires accurate colors. I compromised a bit with the L246W,
a lot less expensive than the more accurate panel types.

Lots of good info on monitors, including specific model recommendations, here:

http://hardforum.com/forumdisplay.php?f=78

The sticky thread on "TFT Technology Breakdown and Model/Panel Index" is
especially useful.

Mark

Post a reply to this message

"Renderdog" <slo### [at] hiwaaynet> wrote in message
news:web.4743e4ee1d741644fb72c6fc0@news.povray.org...
>
> http://hardforum.com/forumdisplay.php?f=78
>
> The sticky thread on "TFT Technology Breakdown and Model/Panel Index" is
> especially useful.

Thanks. I'll check that out.

Post a reply to this message