Hardware, Software Gains Enhance Printing, Plotting

Date: December 7, 1992 More and more, the technological line that distinguishes printers from plotters is blurring. And this convergence in functionality- -enhanced by advances in both hardware and software--is good news for scientists. Hardware has advanced to the point that, in most situations, there is no longer a need for separate output devices for handling text and graphics. While there are still a few drawbacks to this one-device-does-all output approach, especially when both large-size and color output are necessary, many researchers will find these new output units versatile enough to meet most of their publication and data-presentation needs. Moreover, scientists can also enjoy further ease of use thanks to the development of increasingly sophisticated output software-- especially that associated with device drivers. As a result of this development, say vendors and others, scientists will find that the actual connection of computer and output device has become much simpler (see accompanying story). Nowadays, while many researchers can do well with a single output device, a lab's need to work with large-size documents or to present data in color output may still require a separate plotting unit. Any discussion of printers and plotters in the past had to include at least some mention of device drivers--the software routines that convert computer data to languages used by printers and plotters. Today, less needs to be said about device drivers, not because they are no longer needed, but because in newer computer operating environments, such as Windows and Macintosh, device drivers have evolved to the point that users don't have to give them much thought. This aspect of device-driver evolution--becoming transparent to the end user--was advanced primarily by the Apple Macintosh, and is a definite plus for those who want computing to be as hassle- free as possible. But device-driver evolution has taken off in another direction, as well. Device drivers are growing more sophisticated and more powerful as they are refined over the years. This is important for people with older computer systems, as well as those with custom applications or special output needs. In the past, users with older systems "could be hung out to dry" when it came to device drivers, according to Kevin Spangler, marketing representative for Hewlett-Packard Co. in Palo Alto, Calif. Because older operating systems require device drivers that are specific to both the software and the output device, a separate driver is needed for each software application. For example, if you run a word processor, spreadsheet, and database on an older version of DOS, you need three device drivers, one for each of those programs, even though you send output to the same printer. This type of driver works at application level and is usually supplied by the vendor of the application software. "At one point, Lotus had something like 180 drivers available," says Spangler. Now, by contrast, in an operating system such as Macintosh or Windows, only one device driver is needed for all software applications running in that environment. This type of driver is referred to as a "system-level" driver and is supplied by the computer maker or by the printer or plotter manufacturer. If you buy a Macintosh and an Apple LaserWriter, the driver is part of the computer. "Macintosh users don't even know what we're talking about when we talk about device drivers," Spangler adds. "They're spared all of that." On the other hand, if you buy a non-Apple printer to use with a Mac, you get a device driver from the printer manufacturer and install it once on the20computer. The printer can then generate output from all applications running on that Mac. Says Spangler: "Now, instead of every software vendor writing a driver for every device each time they come out with a new package, the onus is off the software vendor and onto the computer or printer vendor." For both users and software developers, this move toward system- level drivers is a definite improvement. But it's also better for the manufacturer of the output device, according to Spangler. "One of our plotters has 84 commands, but the majority of device drivers were supporting something like 10 to 12 of them," he says. "Users were frustrated because they expected more functionality from the plotter, but the device drivers were treating it like it was an Etch-A-Sketch. Now that HP provides the driver, it's done by a team of people who know our products and how to get the most out of them." Device drivers are also not static pieces of software. "They evolve over a period of years. Someone writes one for one application, someone uses that as a shell for something else. They keep getting added to," explains Harvey Lieberman, a software consultant based in Yardley, Pa. As a result, there is some impressive functionality available in device drivers that can be used to "retrofit" older output devices to give them greater utillity, or to handle a custom application or output device. "Device drivers can be as simple as just turning text into italics, or they can be as complex as making a dot-matrix perform like a plotter," Lieberman says. How can a scientist with a particular output need find the appropriate device driver? You can't just walk into the computer store and ask to see the shelf of device drivers. "Calling the vendor [of the output device] is your best shot," Lieberman suggests. "They may have something they support, or they might be a business partner with somebody who has what you need. After that, you could look at network bulletin boards, but if you download anything, you have to worry about viruses." Lieberman also suggests looking in professional journals and talking to others who use similar equipment. --C.P. "I had someone come up to me at a trade show and ask for `one of those printer/plotters,' " says Bill Hart-stein, division manager at Roland Digital Group, Irvine, Calif., a company that makes plotters. But, he notes, "there's still a distinction between the two," pointing out that the difference is particularly relevant when the user requires large-format output. By convention, printer and plotter manufacturers use the letters A through E to represent the range of document sizes. A-size is the familiar 8 1/2" x 11" letter format; E-size documents are nearly three feet by four feet. Says Hartstein: "To get D- or E- size drawings, you're still talking about a plotter." For smaller documents, it's hard to know what to call the newer generation of desktop device that generates text, charts, chromatographs, overheads, and just about any other output imaginable. Is it a printer, because it handles text, including all the fonts now available with desktop publishing software? Or is it a plotter, because it generates graphics? To understand how one output device can handle both text and graphics, and to differentiate among the output options now available, it helps to understand the difference between vector and raster output technology. Vector devices, which have been available for decades, create output in much the same way a human being would. They put down a pen or pencil, draw a continuous line, then pick up the pen or pencil. A vector plotter draws a single line from end point to end point no matter where it goes on the page. Then it draws another complete line, then another, and so on. A pen plotter is a classic vector device. Watching a pen plotter work, one gets a sense of furious activity. Depending on the model, either the paper or the pen is moving back and forth, up and down, as the plotter completes each line of the output. By contrast, the newer raster output devices simply print a matrix of dots. A fax machine producing a message is an example of a raster device in action. Line by line, individual dots are either turned black or left white until the entire page is complete. By making the page's matrix of dots either black or white (in the example of a fax), a raster device can re-create text, graphics, handwriting, and so on. To the device, it doesn't matter what is being produced; dots are either marked or left blank. A raster output device doesn't convey the same sense of furious movement that a pen plotter does; it just emits a quiet hum. Desktop output devices that print both text and graphics use raster technology. Although vector technology has been around longer and still has some advantages over raster, its drawback has always been its relatively slow speed (in spite of the appearance of hyperactivity of pen or paper). The deficiencies of vector devices primarily have to do with their plotting and replotting speeds, says Scott Harlin, vice president of Wilshire Newport Inc., Burbank, Calif., a marketing company specializing in high-technology products. Says Harlin: "These shortcomings set the stage for change--the growing acceptance of raster output devices." Adds Hartstein, "In five years, raster will dominate." The growing acceptance of raster printers has already brought their price down dramatically. They run from several hundred to several thousand dollars. And not only are they affordable, but also their output quality--expressed in dots per inch (dpi) resolution--is very good. Most raster devices generate presentation-quality, 300-dpi documents, and a few are breaking into the 600-dpi league. Laser, ink-jet, direct-imaging, and thermal-transfer plotters are all types of raster output devices. Although many scientists may be content with the A-size, monochrome raster output that has become the staple of the business world, technical professionals can benefit from other features, such as large-format output and color. Large-format output comes in handy for poster presentations, for example, and color is a plus whenever there's a need to convey complex information. Large-format output and color output are not new to raster plotters, but they are finally becoming affordable. For example, Hewlett-Packard Co., Palo Alto, Calif., has a raster printer called the PaintJet that generates color, offers B-size output, and retails for $3,495. For C-size, monochrome documents, Summagraphics Corp., Austin, Texas, offers the HI JetPro. The two JetPro models sell for $1,995 and $2,995. Both the HP PaintJet and HI JetPro are good examples of output devices that could be called either printers or plotters. "They're a hybrid," says Ruth Rhoades, product manager at Summagraphics. "We like to think of the JetPro as an all-in-one solution." For output larger than C-size, raster technology options decrease and pen plotters remain the more affordable, albeit slower, option. "You can get large-format raster devices, but they are expensive," says Hewlett-Packard marketing representative Kevin Spangler. "A large-format electrostatic plotter is fast, but it costs about $20,000. And if you want color, it's more like $40,000." In contrast, E-size pen plotters can be had for under $5,000. These cost estimates, like prices for everything high-tech, will probably drop as the technology is refined and competition for sales increases. Already, for just under $10,000, there is an E- size color ink-jet plotter available from a company call EnCAD, in San Diego. In many lab applications, color is not necessary; but for those who need to convey complex concepts, color is a must. "If the data is complex, or the user is trying to represent a lot of information in one graph, color makes it more understandable," says Rhoades. "Pen plotters are better for this." If there is one area in which vector pen plotters still have an edge over raster models, it is the ability to produce high- quality color output. "You can get color from a raster plotter, but the quality of the color is not as bright as that from a pen plotter," says Hartstein of Roland Digital Group. "I would buy an ink-jet plotter unless I had to have very bold, color-dense charts with extremely high resolution," adds Spangler. "A pen plotter gives bolder lines. You won't get that out of a raster printer, unless you get thermal wax transfer, which is still quite expensive." Color output is useful for more than presenting complex data. In applications such as positron emission tomography and magnetic resonance imaging, a color image provides the best way to interpret results. Here, raster color output devices are better than pen plotters for two reasons. They are not limited to producing lines, arcs, and circles, and they can produce an entire spectrum of colors instead of only the 12 to 14 colors available from pen plotters. At the Brain Imaging Center at the University of California, Irvine, for example, a CalComp thermal transfer color printer generates hard copy of full-color scanned brain images. "It wasn't too many years ago that we were using a 35-millimeter camera to do the work this printer is doing now," says Chuck Tang, software and hardware supervisor at the center. "This actually offers better color for distinguishing various brain structures." For a lab, a raster "printer/plotter" makes a good work horse, especially if the lab's output needs are primarily letter- and legal-size documents that contain a mixture of text and graphics. At the price, the speed and versatility of a raster device are unbeatable. When output needs include large-format documents, the cost- effectiveness of a raster device goes down. Large-format raster plotters are more expensive than pen plotters of similar size. They are significantly faster than pen plotters, however, so a lab generating a high volume of large documents should not rule out a raster device. Although raster ink-jet and thermal-transfer devices provide acceptable color, they cannot yet match the vivid, high- resolution color of pen plotters. Color raster plotters, however, are better than pen plotters for output applications that require color gradients or shades of different colors. Caren D. Potter is a freelance writer based in Trinidad, Calif.

Hardware, Software Gains Enhance Printing, Plotting

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