Classic Computer Magazine Archive COMPUTE! ISSUE 92 / JANUARY 1988 / PAGE 10

Computer Monitors: Making The Right Choice

Clifton Karnes and Randy Thompson

Whether you use your computer for word processing or world-class game playing, your monitor is the most essential component of your system. No matter what computer you own, this guided tour will help you choose a monitor that offers peak performance for your needs.

You'll use your computer's screen, its monitor, more often than anything else in your computer system. It makes sense, then, to take special care when selecting a monitor. The basic question: Do you want color or not?

Color is, of course, important if you plan to play games or work with graphics. On the other hand, all but the most expensive color monitors are harder to read than black-and-white (monochrome) monitors. Also, color monitors can cost anywhere from two to five times more. So, if you're mainly interested in word processing, spreadsheet work, or other text-intensive tasks, you might prefer the sharper and less expensive monochrome.

If you do choose color, but intend to use it often as a text display, you should be sure you will be comfortable reading text on it over extended periods of time. Is the image stable, or does it jitter? Is it sharp, or do the letters blur? There are two basic kinds of color monitors: composite and RGB. Composite, which is a lot like an ordinary color TV, is the least expensive. But, as you might expect, the more costly RGB features colors which are mixed more precisely and appear much sharper.

After you've decided whether or not you want color, your final decision about which monitor to buy will be strongly influenced by which computer you use. Atari ST owners, for example, must · use monitors made specifically for their computer by Atari. To help simplify the decision-making process, here's a list of the monitor options available, separated into computer-specific categories.


There are basically three types of video monitors that you can use with the Amiga: analog RGB, digital RGB, and composite. All Amigas come with RGB output. Most Amiga owners use analog RGB monitors because they provide the best picture and color quality. With the correct cable, you can use a digital RGB monitor like those used on the IBM PC or Commodore 128. These digital monitors, however, display only 16 colors instead of the Amiga's full range of 4,096.

The Amiga 1000 comes with composite color output as well as RGB. The tradeoff here involves image quality. Images that appear sharp on an RGB monitor can look fuzzy on a composite monitor.

Since there are more than 4000 colors available, Amiga 500 owners usually opt for RGB monitors. The Amiga 500 also comes with composite output, but is monochrome composite only. To make up for the lack of color, the monochrome composite output provides a gray scale that produces 4,096 different shades. If you wish, you may hook up a color composite monitor to an Amiga 500, but you'll get a black-and-white picture. Monochrome composite monitors provide a sharp image for text, but when you're using a computer capable of producing outstanding high-resolution graphics in over 4000 different colors, it's something of a waste to view only shades of black and white.

Composite video output is not standard on the 2000. If you wish to use a composite monitor, you must purchase the A2060 composite/RF modulator board.

One type of monitor worth considering is a long-persistence (sometimes called high-persistence) monitor. These monitors are available in both composite and RGB. Long-persistence monitors hold their picture longer than ordinary monitors, thus displaying a steadier image. This can be important when using the Amiga's special interlace modes. With a normal monitor, these extra high-resolution screens tend to jitter. Although more expensive, a long-persistent monitor can be worth the extra cost.

Apple II

With the exception of the Apple IIGS, which has RGB output, there is really only one choice for Apple IIe and Apple IIc owners: a composite monitor. The big decision here is color or monochrome. Monochrome offers a much more readable display when it comes to text, but if you do a lot of game playing, a color monitor might be worth looking into.

With an RF modulator, you can use your television as a video display. Although not the best quality, the family TV offers a tempting low-priced alternative to a dedicated monitor.

The digital RGB output on the IIGS provides a much clearer picture than its composite output. Because of the IIGS's color and graphics abilities, it's advisable to use an RGB monitor if you can afford one.

Atari (Eight Bit)

The Atari 800 family of computers can hook up directly to a TV or a composite monitor. (Atari 400s have TV output only.) Using the Atari's RF modulated output, you can view your computer's screen output via television channel 2 or 3.

To obtain the best picture, you should use a composite monitor. You may connect either a monochrome or color monitor to the composite output. But because the Atari is a color computer with a wide variety of colorful games available, you'll probably want to consider a color monitor.

Commodore 64

Commodore 64 users—like eight-bit Atari users—have three types of monitors from which to choose. First, with an RF modulator, you can use the family TV. The second choice is a monochrome composite monitor, and the third possibility is a composite color monitor.

A TV provides a display that is satisfactory for most applications, but for text-intensive work—like word processing or using spreadsheets—either a dedicated monochrome or color monitor is a must.

The 64's composite signal generates a good, clear monochrome display, but for those who want everything—crisp text and color—only a composite color monitor will do. The 64 has a special type of composite signal that separates chroma (color) and luma (intensity). When this signal—called separated composite—is fed into a monitor that accepts it (like Commodore's 1702/1802), the results are outstanding for a computer in the 64's class.

Commodore 128

The 128, in addition to its 40-column 64 and 128 video modes, has an 80-column color mode. Since a high-quality 80-column display demands a higher-resolution color signal than is possible with composite video—even separated composite—the 128 uses a special video chip (8563) to produce a digital RGB output for its 80-column color screen.

To take advantage of both of the 128's video modes—composite and digital RGB—you'll need either two monitors, or a monitor capable of displaying both signal formats. Be sure that any monitor you're planning to buy will display both composite and digital RGB signals before you make your purchase, since not every monitor is capable of displaying both types. The 128's RGB port is plug-compatible with the one on IBM's color/graphics adapter, so IBM-style monitors can be used with the 128.

The IBM Standards

The IBM PC's open architecture makes it possible to choose the type of video display you want to use. The computer's display circuitry is usually located—perhaps with other options—on an integrated circuit board called a card. (On some IBM compatibles, the video circuitry is built into the system's motherboard.) Video cards can usually be installed and removed without much fuss, so it's easy to change the type of display output you have and, thus, the kind of monitor you use.

Today, in the IBM world, the question of which monitor to use always begins with the question of which video card you have, or want to purchase. In the beginning, though, it was simple.

When IBM first introduced the PC, there were only two display adapters available—the IBM Monochrome Display and Printer Adapter (MDPA) and the IBM Color/Graphics Adapter (CGA). The monochrome adapter was intended for professional use. It produces a clear, easy-to-read text display, but no graphics. The CGA doesn't have as fine a resolution as the monochrome adapter, but as the name implies, it can display color and graphics.

With only two standards, monitor selection was easy. The monochrome card required a TTL monochrome monitor—which is fairly inexpensive—and the CGA card required a digital RGB color display—which is much more expensive. Things started to change when monochrome display users realized they needed graphics capability, too.

Enter Hercules, makers of the Hercules Graphics Card. The Hercules card has the same sharp text display as the Monochrome Adapter and it can produce super high-resolution monochrome graphics. Because of its early support by important products like Lotus 1-2-3, the Hercules card has become a monochrome standard—but one that IBM has never accepted.

Although IBM has introduced several other video standards, most PC or compatible buyers are faced with a decision between a Hercules (or Hercules compatible) card and a CGA. Let's look at both of these options in more detail.

The Hercules Card

The Hercules card has just two monochrome modes—text and graphics. The graphics mode has a resolution of 720 x 348. For applications that don't demand color, it is an excellent, and inexpensive, choice. Hercules-compatible cards are often sold for under $100 and the monitors that support this display can be found in the same price range.

Perhaps the biggest drawback to the Hercules card is that IBM's BASICA doesn't support its graphics, so you can't use BASICA's drawing commands. In addition, many games use graphics and expect a CGA card. One solution to these problems is offered by Chuck Guzis in a program called SIMCGA, which allows a Hercules card to emulate a CGA card. Your display is still monochrome, but you have CGA graphics compatibility.


The CGA card is capable of displaying text and graphics in seven different modes:

40-column monochrome text (320 X 200)
40-column 16-color text (320 X 200)
80-column monochrome text (640 X 200)
80-column 16-color text (640 X 200)
320 X 200 4-color graphics
320 X 200 monochrome graphics
640 X 200 2-color graphics

If you want to use color text, color graphics, or both on your PC, then a CGA card along with a digital RGB monitor is a good choice. The CGA card and the monitor it requires are more expensive than their monochrome counterparts, but the price of these components seems to be dropping almost daily, and once you've been seduced by color, it can be hard to return to monochrome.


In an attempt to combine several standards into one video card, IBM released its Enhanced Graphics Adapter (EGA) in 1984. The EGA was intended to replace the Monochrome Adapter, the CGA, and the Hercules card, and to add new video modes. To take advantage of the EGA's higher resolution you'll need a high-quality RGB monitor like IBM's Enhanced Color Display. The EGA's text modes offer higher resolution than the CGA's and the EGA has the following additional graphics modes:

320 X 200 16-color graphics
640 X 200 16-color graphics
640 X 350 monochrome graphics
640 X 350 64-color graphics

The first two modes offer more colors than the CGA, but at the same resolution. The monochrome graphics mode is IBM's answer to the Hercules card but it is not compatible with Hercules graphics. The last mode, 640 X 350 64-color graphics, requires IBM's Enhanced Color Display, or its equivalent. It combines exceptional resolution with a large palette of colors. As you might expect, EGA cards and EGA-compatible monitors are more expensive than their CGA counterparts, but the price of these products, too, is dropping.


IBM's new PS/2 line of computers offers a completely new video standard and a new video output—analog RGB—which requires an analog RGB monitor. The new adapters used in the new line are the Multicolor Graphics Array (MCGA) for the Model 30 and the Video Graphics Array (VGA) for Models 50, 60, and 80. Why has IBM introduced another video standard that requires a new kind of monitor?

IBM wanted the new PS/2 to have spectacular graphics, which means lots of colors and very high resolution. IBM's analog RGB output can display more colors than digital RGB. With IBM's new analog RGB monitors, each red, green, or blue dot can have any one of 64 different values. This means that 262, 144 colors are possible—quite a palette. No one is sure what the future of the new PS/2 system will be, but it's a good bet that the PS/2's graphics adapters will become a new standard.