Changing Printers

[Fred Ridder]

Paul Findon wrote:
 
> With Mac FrameMaker, changing the printer made no difference to 
> FrameMaker in regard to fonts. With Windows FrameMaker, however, 
> changing the printer causes FrameMaker to display the following 
> somewhat worrying message: "The font information for your system has 
> changed. This change may affect the format and output of your 
> documents."
> 
> Can someone please explain what's actually occurring here, how to 
> avoid any pitfalls, etc?
 
On a Windows system, the font metrics (the precise width and height
dimensions of each and every glyph and space) are part of the printer
driver. When you change from one printer to another, you are also
inevitably changing to a different set of font metrics data, which may
or may not be different in a significant way. If you are switching between
two different PostScript printers of similar resolution, any differences 
should be small enough to be insignificant. But if you are switching 
between PostScript and non-PostScript (e.g. PCL or "clone-script")
printers or between printers of very different resolutions, the tiny 
differences in character-by-character dimensions can add up to a
large enough degree that it can affect a few of your line breaks. And
changes in a line break or two can affect the length of a paragraph;
and changes in the length of a paragraph or two can affect the page
breaks; and changes in page breaks can affect the length of a chapter;
and any change in the length of a chapter can affect the pagination
for a large part of your document and render the page numbers in your
generated files inaccurate. 
 
FrameMaker has no way of knowing whether any of these cascading 
changes have actually occurred when the font metrics were changed, 
but warns you that such changes *might* have occurred.
 
Fred Ridder