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Laser Printing

Users experience transitional problems when moving from a line printer to a laser printer because there are a few differences between the text processors nroff and troff. Nroff is used on line printers like a Printronix while troff is used on laser printers such as an Imagen or an Apple LaserWriter.

If you are used to redefining the page margins, then calling the MM macros with the line ".so /usr/lib/tmac/tmac.m" in your file, you might need to change a few things before running troff instead of nroff. For troff the number registers O, W, and L need to be specified in INCHES!

Nroff margin command: .nr O 15 \"set left margin to 1.5"

Troff margin command: .nr O 1.5i \"set left margin to 1.5"

With nroff, you may use the tbl and neqn pre-processors to do tables and equations. However with troff, you continue to use tbl for tables, but for equations you call the preprocessor, eqn. Troff also has a preprocessor that will draw pictures called pic, one that will draw graphs called grap, and one that will print drawings done in a "MACPAINT" style using the GREMLIN program, called grn.

The important thing to remember when calling these preprocessors is that they need to know what type of printer you are using to print the output. Thus, the -T printer device type has to be passed to troff and each preprocessor. The -Ti240 implies the device type Imagen 240 dots/inch laser whereas another laser device type might be -Tpsc, which implies a postscript device, like an Apple LaserWriter.

The differences between these preprocessors are of major importance to students preparing a thesis or technical report for publication. Documentation concerning nroff and troff can be located in ECN #330 DWB User's Guide and if you are beginning to think about writing your thesis, reading Sample Thesis below might prove beneficial.

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