Font embedding and substitution
A font can be embedded only if it contains a setting by the font vendor that permits it to be embedded. Embedding prevents font substitution when readers view or print the file, and ensures that readers see the text in its original font. Embedding increases file size only slightly, unless the document uses CID fonts. a font format commonly used for Asian languages. You can embed or substitute fonts in Acrobat or when you export an InDesign document to PDF.
You can embed the entire font, or just a subset of the characters used in the file. Subsetting ensures that your fonts and font metrics are used at print time by creating a custom font name. That way, for example, your version of Adobe Garamond®, not your service provider’s version, can always be used by the service provider for viewing and printing. Type 1 and TrueType fonts can be embedded if they are included in the PostScript file, or are available in one of the font locations that Distiller monitors and are not restricted from embedding.
When a font cannot be embedded because of the font vendor’s settings, and someone who opens or prints a PDF does not have access to the original font, a Multiple Master typeface is temporarily substituted: AdobeSerifMM for a missing serif font, and AdobeSansMM for a missing sans serif font.
The Multiple Master typeface can stretch or condense to fit, to ensure that line and page breaks in the original document are maintained. The substitution cannot always match the shape of the original characters, however, especially if the characters are unconventional ones, such as script typefaces.
