Section 16.1. CRT Monitors

16.1 CRT Monitors

Like a television set, a monitor comprises a cathode ray tube (CRT) and supporting circuitry that processes the external video signal into a form that can be displayed by the CRT. Monitors use a different video interface than televisions, have much higher bandwidth, and can display much finer detail. In fact, with the proper adapter, computer video signals can be displayed on a standard television, but only at low resolution. Conversely, a monitor can be used to display television video at very high quality, although doing so requires using a video card with TV input, a tuner, and other electronics that are built into television sets but not monitors. The quality of the CRT and supporting circuitry determines the quality of the image a monitor can display. Because of their higher bandwidth and resolution, computer monitors cost much more than televisions with equal screen sizes.

Monitors comprise the following major elements:

CRT

The CRT is essentially a large glass bottle, flat or nearly so on one end (the screen), tapering to a thin neck at the back, and with nearly all air exhausted. The inside of the screen end is covered with a matrix of millions of tiny phosphor dots (or stripes). A phosphor is a chemical compound that, when struck by electrons, emits visible light of a particular color. Phosphors are organized by groups of three, collectively called a pixel. Each pixel contains one phosphor dot that emits each of the additive primary colors, red, green, and blue. By choosing which dots to illuminate and how brightly to illuminate each, any pixel can be made to emit any one of thousands or millions of discrete colors. For example, 24-bit color allocates a full 8-bit byte to each of the three primary colors, allowing that pixel to be set to any of 256 levels of brightness. Three colors, each of which can be set to any of 256 brightness values, provides a total color palette of 2563 colors, or about 16.7 million colors. The distance between nearest neighbors of the same phosphor color on adjacent rows is called the dot pitch or stripe pitch. A smaller pitch results in a sharper image and the ability to resolve finer detail.

Electron guns

The phosphor dots are excited by one or more electron emitters, called electron guns, located in the neck at the back of the monitor. A gun comprises a heated cathode, which emits electrons, and circuitry that focuses the free electrons into a thin beam. Most CRTs use three separate guns, one for each primary color. Sony Trinitron CRTs use only one gun. There has been much debate about the relative display quality of single-gun versus triple-gun CRTs, both of which have theoretical advantages and disadvantages. In practice, we find the images indistinguishable. The quality of the electronics used to control the shape and positioning of the electron beam is very important to image quality, because the relative position of pixels to electron gun varies with the position of the pixel on screen. Pixels near the center of the screen are oriented at 90 degrees to the gun, and are struck dead-on by the beam. Conversely, pixels near the corners of the screen are struck by the beam at an angle, which, in the absence of correcting circuitry, causes the beam to assume an oval rather than circular shape. High-quality guns correct this problem by changing the shape of the beam according to the position of the pixel being illuminated. Lower-quality guns used in inexpensive monitors do a much poorer job of adjusting the beam, resulting in images blurring near the edges and corners of the tube.

Deflection yoke

The deflection yoke is located around the tapered portion of the CRT, between the guns and the screen. This yoke is actually a large electromagnet, which, under the control of the monitor circuitry, is used to steer the electron beam(s) to impinge on the correct phosphor dot at the correct time and with the correct intensity.

Mask

The mask sits between the electron guns and the phosphor layer, very close to the latter. This mask may be a sheet of metal with a matrix of fine perforations that correspond to the phosphor dot triads on the screen, or a series of fine vertical wires that correspond to phosphors laid down in uninterrupted vertical stripes. The perforations or stripes permit properly aimed electrons to impinge directly on the phosphors at which they are aimed, while blocking excess electrons. This blocking results in a cleaner image, but blocked electrons heat the mask. To prevent differential heating from distorting the mask, it is often constructed of Invar (an alloy with an extremely low coefficient of thermal expansion) or a similar material. Although the mask improves image sharpness, it also dims the image, because areas blocked by the mask cannot emit light, so design efforts focus on minimizing the percentage of screen area blocked by the mask.

In practice, and despite the marketing efforts of manufacturers to convince us otherwise, we find that the mask type makes little real difference. Good (read expensive) monitors produce good images, regardless of their mask type. Inexpensive monitors produce inferior images, regardless of their mask type. Monitors from the best makers Hitachi, NEC-Mitsubishi, and Sony produce superb images using different masking methods. That said, however, there's no substitute for looking at the monitor yourself. You may have a strong preference for the type of picture produced by one of the following mask types:

Aperture grill

The Sony Trinitron television tube appeared in the 1960s as the first alternative to standard shadow mask tubes and has since been used in most Sony monitors. Rather than using the standard dot triads, aperture grill monitors use uninterrupted vertical stripes of phosphors, alternating red, green, blue across the width of the screen. Masking is done by an aperture grill, which consists of a series of very fine vertical wires covering the full width of the tube, and corresponding to the phosphor stripes. In any given vertical phosphor stripe, no mask separates individual pixels vertically, so the top and bottom of each pixel must be delimited by the accuracy of the scanning electron beam. The advantages of the aperture grill are that it allows more electrons to pass than any other masking method, which makes for a brighter, saturated, high-contrast image on screen, and that the absence of hardcoded vertical boundaries on pixels allows using any arbitrary vertical resolution. A minor disadvantage is that the fine vertical wires that comprise the grill are easily disturbed by mechanical shock such as bumping the monitor, which results in a shimmering effect that may take a few seconds to stabilize. Also, the vertical wires are supported by one fine horizontal wire in 14" and smaller Sony monitors, or two such wires (which divide the screen roughly in thirds) on 15" and larger Sony monitors. These horizontal damper wires cast a shadow that some users find objectionable, particularly when they are visible on a light background. The Mitsubishi Diamondtron tube, used in their midrange and high-end monitors, uses similar technology.

Shadow mask

The shadow mask is a perforated sheet of metal whose holes correspond to dot triads, groups of three colored phosphors, which may be arranged in various ways. Three distinct variants of this masking technology are used.

The standard shadow mask is still used, particularly in inexpensive generic monitors and in the "value" models from name-brand manufacturers. The standard shadow mask is a perforated sheet of metal whose circular holes correspond to dot triads, groups of three circular colored phosphor dots arranged at the apexes of an equilateral triangle. The advantages of the standard shadow mask are that it is inexpensive and provides a reasonably sharp image. The disadvantage is that it blocks more screen real estate than other methods, resulting in a noticeably dimmer image, lower color saturation (muddy colors), and less contrast. Also, its triangular pixel arrangement means that vertical lines may show noticeable "jaggies." Standard shadow mask monitors are suitable for casual use, but are not the best choice for intensive use.

The slotted mask, developed by NEC, is a hybrid that combines the stability and sharpness of the standard shadow mask with most of the brightness, contrast, and color saturation of the aperture grill. The slotted mask is essentially a shadow mask in which the small round holes are replaced by larger rectangular slots. Like a standard shadow mask, the slotted mask uses discrete phosphor trios, although they are arranged as rectangular stripes and cover more of the screen surface. The slotted mask design is physically more stable than an aperture grill, while the larger slots allow many more electrons through than does a standard mask. The resulting picture is brighter than a standard shadow mask monitor, but less so than an aperture grill monitor.

The latest masking technology, Enhanced Dot Pitch (EDP) from Hitachi, improves on the standard shadow mask by increasing the size of the phosphor dots and changing their geometry from an equilateral triangle to an isosceles triangle. The larger phosphor dots result in a brighter image with more contrast and color saturation, and the changed geometry provides a better image that resolves finer detail. For example, a standard shadow mask monitor with a 0.28 mm diagonal dot pitch actually uses a 0.14 mm vertical pitch and a 0.24 mm horizontal pitch. A corresponding Hitachi EDP monitor uses a 0.27 mm diagonal dot pitch with a 0.14 mm vertical pitch and a 0.22 mm horizontal pitch. The smaller overall dot pitch renders finer detail, and the smaller difference between vertical and horizontal pitch results in subtle but very noticeable differences in image quality.

16.1.1 Monitor Characteristics

Here are the important characteristics of monitors:

Screen size

Screen size is specified in two ways. The nominal size the size by which monitors are advertised and referred to is the diagonal measurement of the tube itself. However, the front bezel of the monitor conceals part of the tube, making the usable size of the monitor less than stated. Various consumer lawsuits have resulted in monitor manufacturers also specifying the Viewable Image Size (VIS), which is the portion of the tube that is actually visible. Typically, VIS is an inch or so less than nominal. For example, a nominal 17" monitor may have a 15.8" VIS. Small differences in VIS, e.g., 15.8" versus 16", make little practical difference. The smallest monitors commonly available are 15", although a few 14" models can be found. 17" models are currently the most popular, but the rapidly falling prices of 19" models means they may soon overtake 17" models in popularity. 20" and larger monitors are still quite expensive, and are used primarily by graphics artists and others who require huge displays. Table 16-1 lists monitor size and resolution combinations that most people with 20/20 vision find optimum. (++ optimum; + suitable; - generally unsuitable; - - completely unsuitable)

Table 16-1. Suitability of monitor size and resolution

	Monitor size
Resolution	15"	17"	19"	21"
640 X 480	+	-	- -	- -
800 X 600	++	+	-	- -
1024 X 768	-	++	+	-
1152 X 864	- -	++	+	-
1280 X 1024	- -	-	++	+
1600 X 1200	- -	- -	+	++

People with less-than-perfect vision often use the next size larger monitor (e.g., running 800 x 600 on a 17" monitor or 1024 x 768 on a 19" monitor), but we recommend instead using the optimum settings listed and configuring Windows and applications to display larger-than-normal fonts (e.g., set Display Properties to use the "Windows Standard (large)" or "Windows Standard (extra large)" scheme; set Internet Explorer font size to "Larger" or "Largest"; set Word to display text at 150% or 200%, and so on). Using high resolution provides finer-grained images, which are easier on the eyes.

Dot/stripe pitch

Dot pitch or stripe pitch is measured in millimeters, and specifies the center-to-center distance between the nearest neighboring phosphor dots or stripes of the same color. Smaller pitch means a sharper image that resolves finer detail. Unfortunately, dot pitch, which is used to describe shadow mask monitors, cannot be compared directly to stripe pitch, which is used to describe aperture grill monitors. For equivalent resolution, stripe pitch must be about 90% of dot pitch. That is, a 0.28 mm dot pitch monitor has resolution similar to a 0.25 mm stripe pitch monitor.

Maximum resolution

Maximum resolution specifies the maximum number of pixels that the monitor can display, which is determined by the physical number of pixels present on the face of the tube. The maximum resolution of many low-end monitors is identical to the optimum resolution for that monitor size. For example, 1024 x 768 is optimum for 17" monitors, so many low-end 17" monitors provide 1024 x 768 maximum resolution. Conversely, midrange and high-end monitors may have maximum resolutions higher than practically usable. For example, a high-end 17" monitor may support up to 1600 x 1200. There is no real benefit to such extreme resolutions, although it can be useful to have one step higher than optimum (e.g., 1280 x 1024 on a 17" monitor or 1600 x 1200 on a 19" monitor) available for occasional use for special purposes.

Synchronization range

The synchronization range specifies the bandwidth of the monitor, which determines which combinations of resolution, refresh rate, and color depth can be displayed. Synchronization range is specified as two values:

Vertical Scanning Frequency (VSF)

The inverse of the time the monitor requires to display one full screen. VSF (also called refresh rate) is measured in Hz and specifies the number of times per second the screen can be redrawn. To avoid screen flicker, the monitor should support at least 70 Hz refresh at the selected resolution. Within reason, higher refresh rates provide a more stable image, but rates beyond 85 or 90 Hz are necessary only for specialized applications such as medical imaging. Most monitors support a wide range of refresh rates, from very low (e.g., 50 Hz) to very high (e.g., 120 to 160 Hz).

Horizontal Scanning Frequency (HSF)

The inverse of the time the monitor requires to display one full scan line. HSF is measured in KHz, and specifies the overall range of bandwidths supported by the monitor. For example, a monitor running 1280 x 1024 at 85 Hz must display 1024 lines 85 times per second, or 87,040 scan lines per second, or about 87 KHz. In fact, some overhead is involved, so the actual HSF for such a monitor might be 93.5 KHz.

Resolution and refresh rate are interrelated parts of synchronization range of an analog monitor. For a given resolution, increasing the refresh rate increases the number of screens (and accordingly the amount of data) that must be transferred each second. Similarly, for a given refresh rate, increasing the resolution increases the amount of data that must be transferred for each screen. If you increase resolution or refresh rate, you may have to decrease the other to stay within the HSF limit on total bandwidth.

Note that manufacturers often specify maximum resolution and maximum refresh rate independently, without consideration for their interrelatedness. For example, specifications for a 19" monitor may promise 1600 x 1200 resolution and 160 Hz refresh. Don't assume that means you can run 1600 x 1200 at 160 Hz. 160 Hz refresh may be supported only at 640 x 480 resolution; at 1600 x 1200, the monitor may support only 70 Hz refresh.

Resolution and refresh rate alone determine the required bandwidth for an analog monitor. Color depth is immaterial, because the color displayed for a given pixel is determined by the analog voltages present on the red, green, and blue lines at the time that pixel is processed. Therefore, at a given resolution and refresh rate, an analog monitor uses exactly the same bandwidth whether the color depth is set to 4, 8, 16, 24, or 32 bits, because the video card converts the digital color data to analog signals before sending it to the monitor. For purely digital monitors, such as flat-panel units, greater color depth requires greater bandwidth, because color information is conveyed to a digital monitor as a digital signal.

Tube geometry

Monitors use one of three geometries for the front viewing surface. Spherical tubes are used in older monitors and some inexpensive current models. The viewing surface is a section of a sphere, rounded both horizontally and vertically, which results in apparent distortion at normal viewing distances. This geometry keeps the center and corners of the screen close to the same distance from the electron guns, allowing the use of less expensive shadow mask materials and less sophisticated and cheaper electronics. Cylindrical tubes, first introduced with the Sony Trinitron, use a section of a cylinder as the viewing surface, and are vertically flat but horizontally rounded. This keeps the distance from gun-to-center and gun-to-corners similar, while reducing apparent distortion of the viewing area relative to a spherical tube. Flat-square tubes (FST) are actually spherical in section, but from a sphere with a radius so large that they appear nearly flat. The advantage to FST is that the image area is effectively flat, minimizing viewing distortion. The disadvantage is that the electron guns are much farther from the corners than the center, which in turn demands a relatively costly Invar mask and more expensive electronics to provide even coverage. Other than some "value" models, all current monitors, including Sony Trinitrons, use an FST. Don't consider buying a monitor that is not FST.

Controls and stored settings

All monitors provide basic controls brightness, contrast, horizontal/vertical image size, and centering. Better monitors provide additional controls for such things as screen geometry (pincushion and barrel distortion adjustments), color temperature, and so on, as well as an on-screen display of settings. Changing display settings such as resolution and refresh rate may also change the size and position of the image. If you frequently change resolution, look for a monitor that can store multiple settings so that you will not have to readjust the monitor manually each time you change display settings.

Neck length

As 19" monitors become increasingly mainstream, monitor depth also becomes an increasing problem. Historically, most monitors were about as deep as their nominal screen size. With 15" monitors, depth was usually not a problem. With 17" monitors, depth began to be an issue, and with 19" monitors many people found that their desks are not deep enough to allow using a 19" monitor. Manufacturers have responded by producing reduced-depth or "short-neck" monitors. A short-neck 17" monitor is about the depth of a standard 15" monitor, and a short-neck 19" monitor is about the depth of a standard 17" monitor. That shorter neck involves some trade-offs, however. Foremost is the fact that achieving that shorter depth requires changing the deflection angle from the standard 90 degrees to 100 or even 110 degrees. Increasing the deflection angle requires more expensive electronics to compensate and results in reduced image quality. In effect, you pay twice for a short-neck monitor, because it both costs more and provides an inferior image.

16.1.2 Choosing a CRT Monitor

Use the following guidelines when choosing a CRT monitor:

• Remember that a monitor is a long-term purchase. Even with heavy use, a high-quality monitor can be expected to last five years or more, whereas inexpensive monitors may fail within a year or two. We have several 17" monitors here that were purchased with one system and have been moved to two or three successor systems over the years. Good large monitors are inexpensive enough now that it makes sense to buy for the long term.

• Make sure the monitor is big enough, but not too big. Verify that your desk or workstation furniture can accommodate the new monitor. Many people have excitedly carried home a new 19" or 21" monitor only to find that it literally won't fit where it needs to. Check physical dimensions and weight carefully before you buy. Large monitors commonly weigh 50 lbs. or more, and some exceed 100 lbs. That said, if you find yourself debating between buying one monitor and another that's the next size up, go with the larger monitor. But note that if your decision is between a low-end larger monitor and a high-end smaller one for about the same price, you may well be happier with the smaller monitor. A $200 17" monitor beats a $200 19" monitor every time.

• Avoid reduced-depth monitors whenever possible. Space constraints may force you to choose a short-neck model. Just be aware that you will pay more for such a monitor, and its image quality will be lower.

• Stick with good name brands and buy a midrange or higher model from within that name brand. That doesn't guarantee that you'll get a good monitor, but it does greatly increase your chances. The monitor market is extremely competitive. If two similar models differ greatly in price, the cheaper one likely has significantly worse specs. If the specs appear similar, the maker of the cheaper model has cut corners somewhere, whether in component quality, construction quality, or warranty policies.

  Deciding which are the "good" name brands is a matter of spirited debate. Our opinion, which is shared by many, is that Sony makes the best monitors available, although they sell for a significant premium. Hitachi and NEC-Mitsubishi are very close to Sony. EIZO/Nanao, ViewSonic, and (lately) the better Samsung models are well thought of by many. You're likely to be happy with a monitor from any of these manufacturers, although we still recommend choosing one from the first group of three.

  Further down the ladder are "value" brands like Mag Innovision, Princeton, Optiquest, and others. Our own experience with value brands, albeit limited, has not been good. A Princeton monitor we bought died a month out of warranty, as did an OEM Mag Innovision model that we bought bundled with a PC. Two Mag Innovision monitors developed severe problems after only a year or two of use. In our experience, which covers many hundreds of monitors purchased by employers and clients, the display quality of the value brand monitors is mediocre, and they tend not to last long. The same is generally true of monitors bundled with systems. Although there are exceptions, bundled monitors tend to be low-end models from second- and third-tier makers. If you purchase a computer system from a direct vendor, we recommend you order it without a monitor and purchase a good monitor separately. You may be shocked by how little you are credited for the monitor, but that indicates just how inexpensive a monitor is typically bundled with systems. Also, make sure to request that the shipping cost be reduced accordingly. Direct vendors typically charge about $100 to ship the system and monitor, and perhaps $35 less to ship only the system unit. However, some credit the shipping only if you request it.

• Buy the monitor locally if possible. You may pay a bit more than you would buying mail order, but, after shipping costs, not as much more as it first appears. Monitors vary more between examples than other computer components. Also, monitors are sometimes damaged in shipping, often without any external evidence on the monitor itself or even the box. Damaged monitors may arrive DOA, but more frequently they have been jolted severely enough to cause display problems and perhaps reduced service life, but not complete failure. That makes the next point very important.

• If possible, test the exact monitor you plan to buy (not a floor sample) before you buy it. If you have a notebook computer, install DisplayMate on it (the demo version is adequate and can be downloaded from http://www.displaymate.com/demos.html) and use it to test the monitor. If you don't have a notebook, take a copy of DisplayMate with you to the store and get permission to run it on one of their machines. In return for the higher price you're paying, ask the local store to endorse the manufacturer's warranty that is, to agree that if the monitor fails you can bring it back to the store for a replacement rather than dealing with the hassles of returning the monitor to the manufacturer. Mass merchandisers like Best Buy usually won't do this (they try to sell you a service contract instead, which you shouldn't buy), but small local computer stores may agree to endorse the manufacturer's warranty. If the monitor has hidden damage from rough handling during shipping, that damage will ordinarily be apparent within a month or two of use, if not immediately.

• Most mainstream monitor manufacturers produce zero or one 15" model (there's no profit in them), and usually three Good, Better, and Best models in 17", 19", and 21". In general, the Good model from a first-tier maker corresponds roughly in features, specifications, and price to the Better or Best models from lower-tier makers. For casual use, choose a Good model from a first-tier maker, most of which are very good indeed. If you make heavier demands on your monitor such as sitting in front of it 8 hours a day you may find that the Better model from a first-tier maker is the best choice. The Best models from first-tier makers are usually overkill, although they may be necessary if you use the monitor for CAD/CAM or other demanding tasks. Best models often have generally useless features like extremely high resolutions and unnecessarily high refresh rates at moderate resolutions. It's nice that a Best 17" model can display 1600 x 1200 resolution, for example, but unless you can float on thermals and dive on rabbits from a mile in the air, your vision is not likely to profit from that resolution. Similarly, a 17" monitor that supports 115 MHz refresh rates at 1024 x 768 is nice, but in practical terms offers no real advantage over one that supports 85 or 90 MHz refresh.

• Decide which makes and models to consider (but not the specific unit you buy) based on specifications. Any monitor you consider should provide at least the following:

  Controls

  Power; Degauss (if not automatic); Contrast; Brightness; Horizontal Size; Horizontal Position; Vertical Size; Vertical Position; Pincushion/Barrel Distortion Adjustment. Better monitors may add some or all of the following: On-Screen Display; Focus; Individual Red, Green, Blue Color Control (or Color Temperature); Tilt; Align; and Rotate.

  Warranty

  Inexpensive monitors often have a one-year parts and labor warranty (although 90-day warranties, particularly on labor, are not unheard of). Better monitors usually warrant the tube for two or three years (often excluding labor after the first year) with one-year parts and labor on the remaining components. Warranties on high-quality monitors may be for three years parts and labor. In reality, the value of a long warranty on a good monitor is less than it might seem. The few times we've seen a good monitor fail, it's either been soon after it was taken out of the box or after many years of use. Conversely, a two- or three-year warranty on an inexpensive monitor would be useful indeed, because such monitors frequently fail after a couple of years. That's why you seldom find a good, long, comprehensive warranty on a cheap monitor.

  Other specifications vary according to monitor size. Note that shadow mask dot pitches are not directly comparable with aperture grill stripe pitches. A 0.28 mm diagonal dot pitch corresponds roughly to a 0.25 mm stripe pitch. Also, not all dot pitches are specified in the same manner. Some manufacturers specify the diagonal dot pitch. Others, such as Hitachi, specify individual horizontal dot pitch and vertical dot pitch. A monitor specified as having a 0.22 mm horizontal dot pitch and 0.13/0.15 mm vertical dot pitch corresponds roughly to a monitor with a 0.27 mm diagonal dot pitch. The minimum specifications are listed, with preferable values in parentheses:

  15"

  13.8 " viewable image size (VIS); flat-square tube (FST); 0.28 mm diagonal dot pitch; maximum resolution 1024 x 768 (1280 x 1024); 75 Hz (85 Hz) refresh rate for standard 800 x 600 resolution. Automatically synchronize at 31 to 69 KHz (31-80 KHz) horizontally and 55 to 120 Hz (50-130 Hz) vertically. As of June 2002, a high-quality, brand-name 15" monitor can be purchased for $125.

  17"

  15.6" (15.8") VIS; flat-square tube (FST); 0.28 mm (0.27 mm) diagonal dot pitch; maximum resolution 1280 x 1024 (1600 x 200); 85 Hz (100 Hz) refresh rate for standard 1024 x 768 resolution, and 75 Hz (85 Hz) refresh rate at 1280 x 1024. Automatically synchronize at 31 to 69 KHz (31-95 KHz) horizontally and 55 to 120 Hz (50 to 160 Hz) vertically. As of June 2002, a high-quality, brand-name 17" monitor can be purchased for $150.

  19"

  17.8" (18.0") VIS; flat-square tube (FST); 0.28 mm (0.27 mm) diagonal dot pitch; maximum resolution 1600 x 1200 (1920 x 1440); 85 Hz (100 Hz) refresh rate for standard 1280 x 1024 resolution, and 75 Hz (85 Hz) refresh rate at 1600 x 1200. Automatically synchronize at 31 to 94 KHz (31-110 KHz) horizontally and 55 to 160 Hz (50 to 160 Hz) vertically. As of June 2002, a high-quality, brand-name 19" monitor can be purchased for $300.

  21"

  19.8" (20.0") VIS; flat-square tube (FST); 0.28 mm (0.27 mm) diagonal dot pitch; maximum resolution 1600 x 1200 (2048 x 1536); 85 Hz (100 Hz) refresh rate for standard 1600 x 1200 resolution, and 75 Hz (85 Hz) refresh rate at 1856 x 1392. Automatically synchronize at 31 to 96 KHz (31-125 KHz) horizontally and 55 to 160 Hz (50 to 160 Hz) vertically. As of June 2002, a high-quality, brand-name 21" monitor can be purchased for $1,000.

• Choose the specific monitor you buy based on how it looks to you. Comparing specifications helps narrow the list of candidates, but nothing substitutes for actually looking at the image displayed by the monitor. For example, monitors with Sony Trinitron tubes have one or two fine horizontal internal wires whose shadows appear on screen. Most people don't even notice the shadow, but some find it intolerable.

• Make sure the monitor has sufficient reserve brightness. Monitors dim as they age, and one of the most common flaws in new monitors, particularly those from second- and third-tier manufacturers, is inadequate brightness. A monitor that is barely bright enough when new may dim enough to become unusable after a year or two. A new monitor should provide a good image with the brightness set no higher than 50%.

It's worth expanding a bit on what we consider "good" brand names, because that's one of the most frequent questions we get from readers. When we talk to representatives of the various display manufacturers, we always ask them the same question: "Other than your own company, which two or three companies make the best displays?" We hear the same names over and over, and our own experiences and reports from readers confirm which display makers are top-tier.

In the first edition of this book, the Big Four were (alphabetically) Hitachi, Mitsubishi, NEC, and Sony. Since then, NEC and Mitsubishi have merged their monitor operations and a couple of new names have appeared on our list. For CRT displays, we now regard the Big Four as Hitachi, NEC/Mitsubishi, Sony, and ViewSonic, with Samsung close on their heels.

In the past, most ViewSonic models were actually relabeled OEM monitors made by various Pacific Rim manufacturers in bid lots. But when ViewSonic acquired Nokia's monitor operation, in addition to acquiring production facilities they also acquired some serious engineering talent, and their recent models reflect that. When we wrote the previous edition, Samsung was a solid second-tier maker, but they have since devoted significant resources to improving the quality of their displays. Recent Samsung models are, if not quite first-tier, very high second-tier.

Sony has always made excellent monitors, although they were quite expensive relative to other first-tier models, but Sony has finally started reducing the price premium on their monitors. They're still more expensive than comparable models from other first-tier makers, but the premium is smaller than in the past. NEC has become quite aggressive on price, particularly on entry-level models. What's surprising is that they don't appear to have cost-reduced their monitors, so at least for now their construction quality is as good as ever. The fact that NEC monitors still have the three-year parts and labor warranty that is standard for top-tier models bears this out.

In short, there's never been a better time to buy a CRT monitor. Prices are low, quality remains high (at least in models from top-tier makers), and you have several companies to choose among. We'd be comfortable buying a CRT display from Hitachi, NEC/Mitsubishi, Sony, ViewSonic, or Samsung, although we admit to preferring NEC monitors in the entry-level segment and Hitachi models for everything else.