http://pixels.homestead.com/HowTo.html

Dead Pixel: a pixel that reads zero or is always off on all exposures. This
state produces a black pixel in the final image.

Stuck Pixel: a pixel that always reads high or is always on at maximum
intensity on all exposures. This produces a white pixel in the final image.

Hot Pixel: a pixel that reads high on long exposures and can produce white,
shades of red/orange or green pixels. These pixels become more evident with
longer exposures.

Testing for Dead or Stuck pixels

The best way to test for Dead or Stuck pixels is to use a pure white and a
pure red card. Take a picture of each card under normal lighting conditions.
If the pixel is dead it will show up on the picture of the white card as a
black pixel. If the pixel is stuck, it will show up as a white pixel on the
picture of the black card

A common mistake in testing for Dead or Stuck pixels is to cover the lens
with the lens cap, set the camera to a slow ISO speed such as 80 and taking
a long exposure. This produces some red, greenish and sometimes white
pixels.This is a normal state and it is referred to as Christmas Tree
artifacting. The color is caused by the RGB and CMY colored filters of the
CCD. In addition, a dead pixel is dead all the time and would not show up
with this test since the pixel is black.

http://computers.sympatico.ca/viewz/guides/monitor4.html

How to check for dead pixels

When your monitor arrives you need to check it from top to bottom. It's
a bad sign if the styrofoam packing inserts are broken or dented. Damage
caused during shipping can result in a cracked or skewed frame around
the screen or an unstable or distorted image. The real test will be
viewing the monitor under working conditions. If there is a problem,
contact your vendor immediately. A mainstream manufacturer will have a
customer support system you can contact.

A problem to watch out for with LCDs is dead pixels. This refers to
pixels that are either always "on" or "off." After you hook your monitor
up, run a totally white screen and look for stray black dots then switch
to a black screen and check for white or coloured dots. You'll be able
to live with a few dead pixels but you don't want to have a cluster in
the middle of your screen. Warranties differ on how many dead pixels
constitute a defective screen.

One of the best ways to evaluate a monitor is to run diagnostic software
like DisplayMate. You can download free demo versions of some programs
or test your monitor online. The software is designed to help you
optimize contrast, brightness and image size. It provides test patterns
like those you see on TV that test focus, colour and geometry. Running
test programs will help you identify potential problems like
pincushioning (lines tend to curve inward towards the center of the
screen) or misconvergence (coloured halos around objects).

The monitor controls should be able to correct noticeable distortions,
if not there might be a defect in the monitor or the controls. Although
most monitors have the same basic panel of controls, not all monitors
controls are easy to use or effectively adjust the screen. Most users
won't be tinkering with the screen very often, but you can find out
which models are user friendly by reading reviews.

http://www.mitsubishi.ie/releases/10Qs%20re%20monitors_.pdf

10 Issues to Raise When Buying an LCD Monitor
1. Pixel Failure

Pixel failures are the most common complaints in LCD panels, often
occurring in the middle of the screen. Displays certified with
ISO13406-2 guarantees the product will not have more than 3 dead pixels
across its entire screen.

2. TCO99, Energy Star, Energy 2000, TUV Ergonomie, and TUV GS Ratings

These represent the criteria to achieve basic standards for health and
safety and environmental requirements.

3. sRGB Compatibility

SRGB ensures that the colour displayed on the screen is the actual
colour of the product being displayed. If the product does not have
sRGB, the colour shown may not be true to life.

4. Viewable Screen and Bezel Size

Consider overall size, and not just the screen viewing size. Look for a
bezel width of no more than 20mm all around the screen.

5. Viewing Angle

A wide viewing angle prevents washed-out images when viewing the monitor
from the side. Look for a minimum of 120 degree angle on a 15 inch
screen.

6. Detachable Power Cable

Low cost LCDs may feature integral power cables. If there is a fault
with your cable, you will have to return the complete unit.

7. Capability to Maximise Scalable Fonts

Moving from one resolution to another results in abnormal or
inconsistent size fonts. Professional products will offer solutions such
as Portraits Liquid View? to maximise font sizes and ensure uniformity.

8. VESA Mounting Plate

A VESA compatible mounting face allows the stand to be removed and the
panel fixed to a mounting arm, thereby saving space.

9. Brightness

Ensure the minimum brightness is 250cd/m2 for a crisp bright display.

10. Warranty

Warranties should be at least 3 years including the backlight with
preferably an onsite service with a replacement monitor offered should
your monitor need repairing.


http://www.pcmag.com/article2/0,4149,76251,00.asp

# Digital versus analog input.

Though digital and analog connections are supported by both types of
displays, the debate about which is better applies more to LCDs than to
CRTs. The standard VGA-compatible connection takes the digital display
information, which is stored in the graphics adapter's frame buffer.
This data is then sent to the display. If that display is an analog
monitor, the data is sent to a digital-to-analog converter (DAC) and
then out the VGA connector as analog signals. If the receiving monitor
is an LCD, the analog data must be converted back to digital. Because
LCDs are digital, the quality of the signal may diminish as it's
converted from digital to analog and back again. Also, some LCDs have
difficulty synchronizing correctly to an analog signal, resulting in
pixel jitter. A digital signal addresses each pixel directly, so there
is no jitter. Most displays that accept digital signals use the DVI
(Digital Video Interface) connector, but digital inputs are becomi


*  Native resolution. The

actual number of pixels displayed is the panel's most important
specification. Most LCD monitors allow you to scale images of other
resolutions, but you'll get the sharpest result if you stick to the
native resolution.


* Auto-adjust.

If the LCD monitor uses an analog signal, it must synchronized to be
sized and positioned correctly. The best models have a single button on
the front panel that lets you initiate an automatic synchronization
process.


* Viewing angle.

With some LCD panels, viewing the image from an alternative angle can be
difficult to impossible. If you need to see the image when you're not
directly in front of the display, look for a design with a wider viewing
angle. There are different technologies used to achieve this, but you
should be able to view the image at up to 80 degrees off the axis in any
direction.


* Pivoting display.

Some LCDs pivot, so the screen orientation can change from landscape
mode-where the image is wider than it is tall-to portrait mode. Software
rotates the image and reformats it for the new orientation. This feature
lets you view an entire letter-size page in full size on a 15-inch LCD.


* Mounting-arm compatible.

One of the most attractive features of an LCD is that it takes up less
space than a CRT. Many are designed to attach to arms that conform to a
VESA mounting standard, so they can be mounted on a wall, saving even
more space.


* Antitheft lock.

LCDs are fairly expensive and relatively small, making them attractive
targets for theft. Some models include security features, such as
support for a Kensington lock, which can deter pilfering.

* USB hubs.

Some manufacturers build hubs into their displays, and others offer them
as extras for an additional cost. These hubs are little more than a
convenient place to plug in USB devices and are not a particularly
valuable feature. They are valuable only if you have USB devices that
you can't conveniently plug into your computer. Very few monitors use
the USB connection to allow access to the monitor's controlling
circuitry. This would let you adjust the monitor from your keyboard
instead of using the monitor's buttons.


* LCD backlight warranties.

The backlight is a fluorescent lamp that transmits light through the LCD
panel. In some cases, the warranty for this particular feature can be
shorter than for the display as a whole. This means that you may have to
buy a whole new monitor, because backlight coverage has run out. It's
easier to repair or replace the backlight in some LCD monitors than in
others, so if you plan to use this display for a long time, check on the
backlight coverage.


* Dead pixels.

This applies to LCDs only; individual liquid crystal cells may be
permanently stuck on or off, creating a tiny colored dot that is always
on (and often white or black). Many LCDs have flaws, and they may not be
covered by the warranty. You have to expect a certain number of these
pixel defects on an LCD; if manufacturers were to guarantee perfect
panels, the price per display would have to be much higher. Fortunately,
pixel defects are less noticeable on higher-resolution displays. If
you're concerned about this, check the pixel-defect policy before you
buy.


* Speakers.

Some display manufacturers offer speakers as standard or optional items.
The advantage is that they attach to the display and do not require
additional desk space. This is usually a waste of money, because the
quality of the speakers tends to be rather poor, especially when
compared with standalone speakers of similar cost. If you do get a
monitor with attached speakers, make sure there is a quick-mute button
on the monitor panel, or at least an easily accessible volume control.


* SXGA aspect ratio.

Almost all standard display resolutions are based on a 4:3 aspect ratio;
this means that the shorter dimension is three-quarters as long as the
longer dimension. This is the case for VGA (640-by-480 pixels), SVGA
(800-by-600), XGA (1,024-by-768), and UXGA (1,600-by-1200). This is not
the case, however, for SXGA, which is 1,280-by-1,024, or a 5:4 aspect
ratio. If you have an LCD monitor with an SXGA native resolution and
scale images from other resolutions to fill it, circles will appear
squashed. Similarly, if you display SXGA images on a CRT designed with a
4:3 aspect ratio and adjust the image to fill the screen, circles will
not be round. This is not a problem for most users, but if you're doing
precision work, such as drafting or desktop publishing, this could cause
problems.

# Check the warranty. Most manufacturers offer three-year coverage, so
don't settle for less.


# Make sure you can return the display easily if it's flawed. There can
be a lot of variation among individual units of the same model, so you
may be surprised when you open the box.


# If you're buying an LCD, find out about the exchange/return policy
terms regarding pixel defects.


# The only thing likely to wear out on an LCD is the backlight;
investigate if and how it can be replaced.

tuning contrast and brightness

http://www.inforamp.net/~poynton/PDFs/Brightness_and_Contrast.pdf