Why text in Zapf-Chancery-Medium-Italic font become smaller when printed via pdf conversion ?

Your hunches may be correct!

There are many cases in which the printer-resident fonts matching the name of a host computer font may have different designs, different metrics, or even different character sets yielding even worse issues than you report.

At Adobe, we obviously can't comment on or for that matter assist with Windows/GhostScript software, but based on what could happen with Acrobat Distiller, we are fairly confident that similar issues occur with any conversion of PostScript to PDF. Note that if your non-Adobe PostScript to PDF software has “resident” fonts, they are very likely knockoffs of the standard Adobe PostScript printer resident fonts and all bets are off.

The idea of “printer-resident fonts” dates back to the earliest laser printers where communication speeds between the host computer and the printer were very low and most if not all computers did not have scalable type for display (at best, finely tuned bitmaps were used to approximate the printed results for WYSIWYG word processors, layout programs, and graphics software.

Today's printers are most often connected via wired or wireless Ethernet or at worst, USB — all of which are much faster than the RS232, AppleTalk, and parallel ports of day long gone. The time to download fonts for each job is miniscule.

However, for both Windows and MacOS, for PostScript printers, if the font used in your work is printer-resident (as determined by an entry in the printer's PPD file), then the driver (or application) will typically avoid downloading the font within the PostScript stream and defer to the font definition in the printer. (Some applications do have options in their print dialog to always download PPD fonts – if your application has such an option, use it!)  Note that all recent vintage versions of Acrobat / Adobe Reader never, repeat never rely on printer-resident fonts; they use the fonts embedded in the PDF file itself or if the font is not embedded, the equivalent or a replacement font installed on your system.

One way to trick your applications and/or driver into not using printer-resident fonts is to edit the PPD file and eliminate all the font entries except for Courier. At Adobe, we strongly recommend that you do such edits! Note that if you are editing a live .PPD file under Windows, save a copy of the file first, and after you finish the edit, delete the corresponding .BPD file. A reboot would not hurt!

          - Dov