CNET Editors' monitor buying guide
Judging image quality
Image quality, the most important feature of a monitor, is also the hardest to judge. Good is a subjective term, so relying on the judgment of reviewers (such as
CNET) may not get you exactly what you want. Further, like a snowflake,
every monitor is unique. There can be significant differences from one
monitor to another--even among the same make and model. It's
unrealistic to expect to run a comprehensive diagnostic on a monitor
before you buy it, but here are some of the most important qualities to
look for when choosing a CRT or an LCD. We've also included a few
simple tests you can do in the store to assess image quality.
Quality control:
LCDs: What to look for |
Tips and tricks: Assessing LCD image quality |
CRTs: What to look for |
Tips and tricks: assessing CRT image quality
LCDs: What to look for
Choose a monitor that automatically adjusts to the timing of an
analog (VGA) signal. You want to see stable gray and patterned images
with no pixel jitter.
Find a monitor with good viewing angles. Colors and brightness
should not change in the corners of the screen, where the viewing angle
is the greatest.
Pick a monitor that looks uniformly bright when viewing both dark and light images.
Tips and tricks: Assessing LCD image quality
Check for dead pixels, ones that are always off. It's not uncommon
for monitors to have one or two defective pixels--especially larger
models--but you want as few as possible. Open Internet Explorer, in the
address line type about:blank, and press Enter. Then press the
F11 key to make it full-screen. Look for small black specks that are
not dust or debris on the screen. (Press F11 again to see the Explorer
toolbars.)
Check for stuck pixels, which are always on. Right-click the
Windows Desktop, pick Properties, then choose the Screen Saver tab.
Choose Blank from the list of screensavers, then hit the Preview
button. Look for any glowing red, green, or blue spots. (Press any key
to return to the Display Properties window.)
CRTs: What to look for
Find a monitor with good convergence (clean white lines with no colors on the edges), as this increases image sharpness.
Choose a monitor with good screen geometry, especially if you intend to use it for design or drawing tasks.
Pick a monitor with good image regulation; you want an image that
does not change its dimensions or distort when the content of the image
changes. Poor image regulation can be a problem with lower-priced
models and displays that are operated at the upper limits of their
specifications.
Tips and tricks: Assessing CRT image quality
Check the convergence
of the display. Open Windows Paint and start a new image. Choose Image,
then Attributes, and change the size of the image to the same number of
pixels as the current resolution (to check the resolution, right-click
anywhere on the desktop, select Properties, then choose the Settings
tab). Use the Fill tool to fill the screen with black. Then choose the
Rectangle tool, set the drawing color to white, and draw a box that
fills the screen, starting in the upper-left corner. Scroll to the
bottom-right corner of the image and draw another box that fills the
screen. Now choose View, then View Bitmap to see the image on the full
screen. You should see a black screen with two intersecting white
rectangles. Check the white lines closely; you should not see any areas
where the lines separate into colored lines. A slight color tinge along
the edges of a line is acceptable, but a pure white line is best.
Display convergence.
Check the screen geometry.
Look to see that the lines drawn in the previous step are straight. You
can also draw a circle in the center of the image using the Circle tool
(hold Shift down to draw a perfect circle), then copy and paste the
circle in the corners and along the edges. Look to see that they are
round--not squashed or egg-shaped.
Good geometry.
Bad geometry.
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