You've got to make a big presentation and preparation has carried over into your personal time. So you bring work home. Problem is, your home printer isn't capable of reading the commands required of your laser printer at the office. The two printers' outputs are mismatched; since the printers use different typefaces and spacing, line length and page breaks vary considerably.

What do you do? Delete all the laser printer commands at home and re-input them when you get back to the office? Run out and buy an expensive laser printer to replace your not nearly as expensive but perfectly capable dot matrix printer? Neither.

The solution is printer-emulator software, which can make a low-cost printer behave like a laser printer. You'll still want to print the final copy on a laser printer, but your low-cost printer will work fine for layout and proofing.

The most sophisticated laser printers use a page-description language called PostScript. PostScript emulation software lets you process the language on a microcomputer at minimal cost. Your computer must have at least a megabyte of memory to run the program, and even at that expect printing to be slow.

UltraScript (from QMS Inc., 800-635-3997) is the leading software emulator for PostScript. It's available for IBM PCs and compatibles (with at least an 80286 processor) and Macintosh computers. UltraScript comes in two versions; a $140 version that includes basic typefaces and a $275 version that comes with more typefaces. UltraScript supports many printers, including models that sell for less than $200. For the best results -- short of a laser printer -- try the Hewlett-Packard DeskJet (for the IBM PC, $600) or DeskWriter (for the Mac, $800).

Hewlett-Packard's LaserJet printers are the most popular laser models for IBM PCs. Since some LaserJets now sell for less than $1,000, LaserJet emulation has been less important than for PostScript printers, which are higher priced. Nevertheless, LaserTwin (Metro Software Inc., 800-621-1137) software enables a wide range of printers to emulate a Hewlett Packard LaserJet series II printer. It sells for $250 including typeface package. All prices quoted are approximate retail prices.