I was almost overwhelmed with the responses to my "Double the Fun with Multiple Monitors" article in TidBITS-421. It seems that many people use multiple monitors, and those people who have several screens are as addicted to them as I am.
Finding Another Monitor -- Several people bemoaned the cost of using multiple monitors. I sympathize with the problem and agree that it's not easy to find video cards and monitors for free; however, with an inexpensive monitor adapter most Macs can use most PC monitors. It's best to use a multisync monitor, but even a straight VGA monitor should work. [In addition, Marc Zeedar
It's almost impossible to buy new grayscale monitors these days, but the fact that many consider them outdated may prove helpful in finding a cheap used one. You can use it for situations where color isn't important (such as network monitoring, email, or word processing).
A few people commented that if you have an AV Mac with video-out capabilities, you can use a television as an additional monitor. The resolution isn't great, and you may need extra VRAM, but it's a decent way to preview Web pages at 640 by 480.
Running Interference? Many readers asked about interference between monitors pushed close together, resulting in waviness or color shifts on one or both monitors. I'd forgotten about this problem since upgrading to my Apple 21-inch monitors, since they don't suffer interference problems. However, here are some suggestions for eliminating interference.
Move the monitors apart until the interference goes away. This is what I did with one set of monitors long ago, and although I didn't like the inch of space between them, it was acceptable. Tonya solves the problem by cocking her monitors so the fronts touch but the backs are several inches apart.
Make sure the interference isn't caused by video or power cables overlapping each other. Geoff had this problem after his kittens redecorated behind his desk.
Set monitors so they run at the same refresh rate, if possible. You can see and choose the rate in the Monitors & Sound control panel; the rate appears as the number listed after the resolution, as in the "67" in "640 x 480, 67 Hz."
Use newer, low-emission monitors, which are generally better shielded than older screens.
Check for sources of emissions nearby. I've noticed problems if AC power adapters are plugged into the same power strip as my monitors.
Place metallic shielding between the monitors. I've heard a couple of suggestions for the metal to use, ranging from steel to tin to lead, but if anyone can offer a definitive explanation and shielding solution, please let me know.
Other Uses for Multiple Monitors -- Probably the most commonly suggested use for a secondary monitor was to store the many palettes used by desktop publishing and graphics applications. Putting those palettes on a cheap 13-inch monitor frees up space on the primary screen, which is often an expensive 21-inch color monitor running at 24-bit color. Victor Gavenda
"It's important that the two monitors are closely matched in color, so when you pick a color from the color palette it looks the same in your image. For this reason I always specify Trinitron monitors and make sure they're set to the same color temperature and gamma. I find it best to pick resolutions for the two monitors that give you the same or nearly the same "pixels per inch" (not necessarily the largest supported resolution); so that type, for example, appears the same size on either monitor. It's easy to check this by choosing a desktop pattern that features an obvious repeating pattern, or by dragging a small window so it straddles the monitors, and see if the edges line up."
Those who work in Macromedia Director also benefit from multiple screens. Max Heim also noted that when he did Director work, he used three monitors: a 20-inch color monitor for the Paint and Cast windows, a 20-inch grayscale monitor for the Score window, and a 13-inch color screen for the Stage.
Web designers chimed in loudly in favor of using multiple monitors so you could write HTML on one screen and preview it on another. Inexpensive monitors running at 640 by 480 are popular, since they provide a least common denominator reality check. Finally, a few mentioned using three monitors for previewing in both Netscape Navigator and Internet Explorer. Web designers doing double duty as network administrators also found secondary monitors useful for keeping network status windows open.
Programmers also claimed a special need for multiple monitors to keep a debugger open on one screen while an application runs on the other. I'd also encourage programmers to use multiple monitors to make sure their applications behave properly on multiple monitors. Some applications don't zoom properly on a secondary monitor, and I once saw an application that actively prevented you from moving its window to the secondary monitor.
Several folks who use either SoftWindows, Virtual PC, or PC Compatibility cards noted that it's easier to work back and forth between the two operating systems if each has its own monitor. I've certainly found this when controlling my PC via Timbuktu.
Finally, the gaming crowd strongly recommended ParSoft Interactive's A-10 Attack and GSC's F/A-18 Hornet 2.0 - a pair of flight simulators that use multiple monitors for additional views (though reportedly, subsequent versions of F/A-18 Hornet dropped multiple monitor support when the program went cross-platform).
Utilities -- A number of people passed on utilities that they found useful when working with multiple monitor setups. For those not running Mac OS 8, several readers suggested the Secret Finder Features extension, which enables the Command-Delete keyboard shortcut for sending selected files to the Trash, a great time saver when the icons in question are far from the Trash. Similar features are available in the equally unauthorized Hidden Finder Features control panel.
Another popular utility, WestCode's OneClick, can be scripted to reposition windows automatically for poorly behaved applications that don't properly remember window positions. In addition, there's a Load/Save Desktops button for OneClick that can restore Finder icons to a pre-assigned configuration, which is useful if you do anything that confuses the desktop layout. If you're just concerned about Finder windows, Brookline Software's Window Set Manager can be useful for opening and positioning sets of windows for a particular project.
For those who just can't afford a second monitor, Martin Sweitzer recommends Virtual, a $10 shareware utility that provides a larger virtual screen as well as several virtual screens. Virtual might also be useful for those of us who still use SE/30s as servers, since occasionally I run across software that simply requires a larger screen.
PowerBook Users -- Finally, a number of readers wrote that the only reason they weren't upgrading to a new PowerBook was the lack of multiple monitor support. However, at least PowerBook 1400 users have some hope. John W. Fox