Flat Monitors [OT]

[Dean S. Messing]

Robin Laing wrote:
: Dean S. Messing wrote:
: > Tim wrote:
: > : Where I work, in television, where they do buy horrendously expensive
: > : monitors, they will not touch LCDs for anything other than monitors that
: > : aren't paid close attention to.
: > 
: > That's because studio people are notoriaously over-conservative.  (I
: > worked with them extensively at Tektronix.  Trying to get them to use
: > digital scopes in the beginning was like pulling teeth.  At one point
: > we had to put a circuit into one of our products to make the noise
: > floor "look analogue".  It was entirely artificial but it made the
: > studio engineers happy.)
: 
: I will agree with you.  They prefer tools that they are familiar with. 
: Don't like change.  Heck, some would still be using U-matic recorders if 
: they could get a new portable one.  :)

And claim that they have better recording charateristics in A/B tests than modern
digital recorders!  

: > 
: > : CRTs far exceed them in all the things
: > : you just mentioned.
: > 
: > This is simply false.   You don't appear to have looked at
: > the specs in a while.
: 
: I have looked at the specs as I am trying to purchase a new computer 
: system for my work.  I have yet to see a LCD monitor that provides all 
: the specifications that meet the present CRT that I am using.  The 
: killer is the static contrast.  I have seen a few that promote 5000:1 or 
: 8000:1 contrast but when you read the fine print, this is only for 
: dynamic contrast.  Some of them have static contrasts in the 300:1 to 
: 500:1 range.  Pretty low for working on static images.

For computer monitor grade panels this is correct.  But for the next
generation modulated LED backlit displays the static contrast is very
large, as is the max cd/m^2.  That's because in dark areas the
backlight is off so very dim so there's no leakage thru the pixels.
These won't be available as Joe Sixpack computer monitors for some
time, but for studio quality, or home theatre quality viewing they are
right around the corner.  As I've said already, their specs (as
carefully measured by trained metrologists) exceed the best CRTs,
despite what certain people on this list want to believe.  And we
are not talking about specsmanship and fooling around with special patterns
to get the best numbers.  We are talking worst case static C.R.

But (again) these are for spendy applications, not the average desktop
monitor.  (However even for reasonably priced LCDs, CRT specs are now
exceeded in several categories: gamut, brightness, and MTF (moducation
transfer function, not mean-time-to-failure) being three. That's why text
on an LCD with a given native resolution looks so much sharper than
on a CRT scanning at the same resolution. 

It is important that the LCD be operated at the native resolution (so
called "dot-on-dot") or text and images will look poor.

: > : The contrast range of the LCD is inferior, and
: > : that's the basis of all the other measurements.  With a poor contrast
: > : range, you can't get the full colour gamut.
: > 
: > Again, you don't appear to have looked at the specs recently.  At the
: > last CES, I saw LC displays with contrast ratios exceeding 10000:1 made
: > by every major manufacturer except Phillips.
: 
: I have yet to see one LCD monitor that provides a static contrast of 
: 1000.  

I have three in our lab that spec out at 50000:1, one with max brightness
that approaches outdoor daylight. Have a look at:
<http://www.dolby.com/promo/hdr/technology.html>

: The high contrasts specified are all dynamic contrasts done by 
: changing the intensity of the backlight.  

On cheap panels that advertise 5000:1 you are correct.
For high-end stuff, with modulated backlight, it's static.

: Can you provide one 
: manufacturer that makes a high contrast (Static) LCD monitor?  I may be 
: interested in purchasing it.

I gave you a link above.  But you are not interested in purchasing it :-)
But in about three years they will be available.

On the other hand, the LCD has so many other advantages, like high brightness,
colour gamut, and MTF that I wouldn't live w/o one.  I have a high quality
Panasonic CRT and high-end LCD with a KDE desktop spanning them.  Whenever
I look at text on the (well-adjusted) CRT, I feel like squinting because it
is so blurred compared to the LCD.  That's due to the Gaussian Spot profile of the CRT
compared with the pixel profile of the LCD.

There's also a type of sampling that's called subpixel subsampling
that gives about 1.5 times more horizontal resolution on a striped
pattern LCD.  This type of sampling will not work on any CRT.

Also, 1920x1080 (so-called "full HD") LCDs are now common and
relatively inexpensive.  What's the current price of an HDTV CRT?

There's much more that I could say (about new sampling geometries,
multiprimary displays, white subpixel displays, etc).


: 
: > The best CRTs (measured in a dark room) don't usually don't exceed
: > 6000:1.  And a new generation of LCD is already being introduced by
: > nearly every manufacturer that uses so-called dynamic backlight
: > modulation. These have contrast ratios exceeding 100K:1
: 
: I need high contrast in static images for my work.  This dynamic 
: backlight is useless when comparing individual frames from highspeed 
: cameras looking for a subtle change in the contrast to see shock fronts.

Why don't you tell me more offline? Your application sounds
interesting.  I'm happy to discuss it with you.  You may be
misunderstanding "dynamic backlight."  An old technology merely dimmed
the backlight as a function of the luminance histogram.  That's not to
what I'm referring.  Image an array of LEDs (and appropriate diffusion
screens) behind the LCD that is spatio-temporally modulated.  In dark
areas of the image the LEDs are dimmed below their average, in
highlights, they are brightened above their average. If the LEDs are
RGB, this can be done in each colour plane to not only increase
luminance contrast but chrominance contrast as well.  That's what is
now called "dynamic backlight" or "area active" backlight.  With very
bright LEDs (as in the link above), 16 bits of dynamic range are
achievable.

: I think it is useful to allow others to learn.  There are some people 
: that can learn from these discussions.  Marked OT is a good idea though.
: 
: In this thread I have learned about RGB LED backlights.
: 
: FWIW, I just read a forum post about laser driven monitors that are 
: supposed to be shown in January.  Could be even better than OLED or SED.
: 

Ok. I'll wait to see if anyone screems about cluttering up the Fedora
list with irrelevant junk. :-)

Dean