If you're planning to buy a computer monitor, the first thing to consider is how it will be used. If you use desktop applications such as word processing, email, programming, etc., an LCD (Liquid Crystal Display) monitor will probably be an acceptable choice, but if you perform photographic color correction and need accurate color a CRT (Cathode Ray Tube) monitor is likely the better option. What follows is a discussion of how monitors work and what to look for when buying a monitor.

If you're into high-end photographic work, CRT's are still the better choice, but they've become quite expensive and are more difficult to find. Recent advances in the LCD technology are improving the contrast ration and viewing angle, while also reducing the price.

If you need high-end results, the CRT still remains the best option, but its biggest shortcomings are its size and weight. Like it or not, a CRT can take up a lot of room on the desktop, unlike an LCD monitor which will be much smaller, lighter and thinner.

How a CRT Monitor Works

A CRT monitor is made up of a large (and heavy) glass tube which contains an electron gun at one end and a thick glass screen coated with phosphors at the other end. In a color monitor, there are three electron guns (red, green and blue).

Note: Part of the reason that these tubes are so heavy is that they contain a vacuum - if the tube becomes physically damaged it can implode).

As electrons are fired, magnetic coils direct the electrons to hit the correct point on the screen. With a color screen, the phosphors are in a triad formation. As the electron strikes the corresponding dot, it glows with light. The screen is redrawn multiple times a second, so if you have a setting of 60 Hz, the screen is redrawn 60 times.

How a LCD Monitor Works

The acronym LCD is short for Liquid Crystal Display. Essentially, LCD displays are made up of liquid crystals and the manufacturing of these devices is much more involved than for a CRT display. The LCD uses a matrix of crystals that make up a film for the display. The colors in the display are turned on or off when an electrical current is applied to them. Behind the film is backlight which illuminates it so it can be seen under any lighting condition.

Differences between CRT and LCD Monitors

Essentially the pros of CRT monitors are durability, multisync capability, variable refresh rates and a wide color range. CRT monitors offer a contrast ratio of 700:1, meaning that darker colors may appear as black, a hindrance to graphics professionals and gamers.

The cons of CRTs are that they tend to be large, heavy, they use large amounts of electricity, they create energy fields that can be harmful to users and they generate a lot of heat. Other issues: soft focus flaws that create blurred edges and screen flicker, though the latter can be eliminated by setting the screen refresh rate to a higher setting, such as 85Hz (your video card will need to have this option available).

With an LCD display, the most obvious pros are that they occupy a relatively small amount of space, they're lightweight, energy efficient, there are no flicker issues and they reduce eye fatigue.

The cons are expense, few resolution options (images not at native resolution tend to be blurred), fragility, screen refreshes are slow (creating blur with fast moving images), image quality changes when viewed from different angles and the LCD panels have poor color contrast (see above). Another issue concerns dead pixels, a common problem with LCD screens. If you have more than a couple and they annoy you with their placement on the screen, take the monitor back.

Tips for Buying a CRT Monitor

Generally, the best overall purchase is with a 19 inch flat screen monitor, with a dot pitch of .26 or less (the distance between two dots on the screen) and power saving options. Be aware that if you decide to go to a 21 inch monitor the size and cost jump considerably.

CRT resolution is adjustable and can go as high as 1600x1200 or more, but in order to take full advantage of these resolutions your video card needs to have that capability as well. An anti-glare coating is recommended as it makes images clearer, reduces eyestrain and is a must for a CRT monitor.

When considering a monitor, the viewing area (measured diagonally) is important. As a case in point, a 17 inch monitor refers to the entire screen and frame, but the actual viewing area might only be 15-16 inches across. If in doubt, take a tape measure with you. Also, measure your desk space in advance. It will save you the hassle of having to return a monitor later.

Warranties vary from 1-3 years. Additional warranties that you can purchase onsite are another option and may be a good idea. When your monitor warranty expires it's a good idea to find out who will service it.

Tips for Buying an LCD Monitor

LCD monitors use a fixed matrix of cells for image display and this is the resolution that offers the best result. If you reduce the resolution, only a portion of the pixels are used, resulting in a blurry image. Make sure that the native resolution matches the one you use regularly.

Dead pixels are a problem with LCD screens. To see if your screen has them, look at a completely white screen and see if you can spot any black dots, then change the screen to black and see if any white or colored dots appear. Having two or three might not be much of an issue, unless their placement is in a critical location. If that's the case, take the monitor back. The worst part about dead pixels is that they're not easily fixed. Before you plunk down your hard earned dollars, check the warranty and see what it offers/excludes. Find out how many dead pixels your screen has to have before it can be replaced. In some case that's eight; which is too much, in my opinion. If necessary, consider purchasing an extended warranty.

As mentioned earlier, the contrast ratio is an important issue. If the contrast is too low, the screen could produce dull, flat colors and darker color shades could appear as black. Look for a contrast ratio 400:1 or better. If it's lower than that, colors may wash out at higher brightness settings. Be aware that higher contrast ratios are good only so far. Anything over 600:1 isn't likely to offer an advantage.

Note: These days most LCD monitors have a contrast ration of 700:1 or better. If in doubt, check the specifications. The viewing angle needs to be as wide as possible, preferably 120 degrees or greater. This important if color manipulation and working with digital images.

Check the response time (if listed), which is the time it takes for an individual pixel to glow white, then black and glow white again. Traditionally, that referred to the time it takes for the crystals in the panel to go from an on to off state, but now refers to a gray to gray rating. This is creates a shorter time than the traditional reponse times. These days, LCD monitors have a response time of 8 ms or less.

While you can use an analog connection to your computer from the LCD panel, you'll get a sharper image if you use a DVI (Digital Video Interface) connection. You'll need to find a monitor that offers DVI, a video card that uses it as well and the corresponding connectors.

As with a CRT, the viewable area varies from manufacturer to manufacturer. If in doubt, measure it.

Conclusion

How do you decide what monitor is right for you?

If you're a graphics professional the CRT still displays more accurate color than an LCD monitor, but that gap is closing. If you're into high-end work, the CRT still holds the lead, but if not, a high-end LCD could work for you. If you work in professional graphics space you're likely to want a dedicated system, meaning that the graphics platform is kept in an environment where the light can be controlled. In that situation, portability is not likely to be an issue. Finally, monitors tend to have a long life on the average and it's possible to use the same one for many years, unlike your computer, which becomes obsolete very quickly. I recommend you spend as much as your budget allows; you'll appreciate it later.

Hardware Calibration

An important option is to get a hardware calibrator for your monitor so you can configure it for your space. Controlling the environment is important. If you can't, your color results will be unpredictable.

© Nathan Segal.