Before you begin, check your printer driver to see if printing in poster format is an option. It will save you a lot of time and effort. Big thanks to the aware Karel Jansens for the printer driver tip.
Step 1: Save your Word Document as a TIFF file
1. On the File menu, click Print.
2. In the Name list in the Print dialog box, click Microsoft Office Document Image Writer.
3. Click Properties.
4. In the Microsoft Office Document Image Writer Properties dialog box, click the Advanced tab.
5. Under Output format, select the TIFF - Monochrome Fax option, Superfine 300 DPI and then click OK.
6. In the Print dialog box, click OK.
7. In the Save as dialog box, select the View Document Image check box, and any additional options you want, and then click OK.