By default, each page is scaled to reflect the image dimensions and resolutions stored in the file. The -x and -y options can be used to specify the horizontal and vertical image resolutions (lines/inch), respectively. If the -S option is specified, each page is scaled to fill an output page. The default output page is 8.5 by 11 inches. Alternate page dimensions can be specified in inches with the -W and -H options.
By default fax2ps generates PostScript for all pages in the file. The -p option can be used to select one or more pages from a multi-page document.
fax2ps generates a compressed form of PostScript that is optimized for sending pages of text to a PostScript printer attached to a host through a low-speed link (such as a serial line). Each output page is filled with white and then only the black areas are drawn. The PostScript specification of the black drawing operations is optimized by using a per-page dictionary of the most common horizontal move-draw operations required to fill the black regions on the page. This compression scheme typically results in a substantially reduced PostScript description, relative to the straightforward imaging of the page with a PostScript image operator. This algorithm can, however, be ineffective for continuous-tone and white-on-black images. For these images, it sometimes is more efficient to send the raster bitmap image directly; see tiff2ps(1).
The compressed PostScript description uses codes constructed from an extended alphabet of safe characters (i.e. those characters whose concatentation are unlikely to be interpreted as a PostScript operator or name). By default, this alphabet is comprised of upper-case alphabetics as well as some other printable characters. To restrict the alphabet to only upper-case alphabetics, the -a option may be used. To force fax2ps to include statistics about the effectiveness of the generated code dictionary in the output PostScript file, the -s option may be specified. (The statistics are included as PostScript comments.)
Various messages about badly formatted facsimile images may be generated due to transmission errors in received facsimile. fax2ps attempts to recover from such data errors by resynchronizing decoding at the end of the current scanline. This can result in long horizontal black lines in the resultant PostScript image.