PDF Optimizer

Fonts

Optional. Enable any of these values by adding it to the profile and setting it equal to ON.

subset-embedded-fonts Subsetting fonts removes unused characters from font files embedded in the PDF.

It is a best practice when working with PDF documents to embed all of the fonts used in that document into the document itself. That way, the viewing tool (like Acrobat) does not have to look for a font on the local system, or choose a substitute. But embedding font files in a PDF document can make the PDF quite large, especially if the PDF has embedded a font file for an Asian language, such as Mandarin, with tens of thousands of characters.  To avoid this, a subset of the characters in the font can be saved in the PDF document. The subset font only includes the characters you expect to need when rendering the pages of that document. This often leads to a much smaller PDF.

Note that with a subset font the reader of the PDF file might not be able to edit the file, such as by using the Adobe Acrobat editing tools. This is because some new characters that the reader may use might not be included in the subset font. 

consolidate-duplicate-fonts Remove multiple copies of the same font file.

Fonts are commonly embedded in a document to make sure that the PDF can be rendered on any platform, as described above.  The fonts travel with the PDF, so the file will open and display properly whether the same fonts are installed on the local machine or not. It is also possible to save space by including a subset of a font in a PDF document.  Sometimes, however, PDF documents are created with multiple copies of the same font, either as multiple subsets or multiple, fully embedded copies of a font file. When multiple copies of the same font appear, they may be merged into a single font.

Sometimes different versions of a font in a PDF document share the same name. In this event these named fonts are not merged.

unembed-standard-14-fonts Remove the standard set of Base 14 fonts.  Defaults to on. The Base 14 fonts are five typefaces installed with Adobe Acrobat and commonly used with PDF documents:

  • Times Roman: standard, bold, italic, bold/italic
  • Helvetica: standard, bold, italic, bold/italic
  • Courier: standard, bold, italic, bold/italic
  • Symbol: mathematical and special purpose characters
  • ZapfDingbats: small printer ornaments, like check marks and pointers

When these standard fonts are embedded in a PDF document they can make the file considerably larger. By default, this value is turned on, to automatically unembed these standard 14 fonts. Then, when the optimized PDF document is opened in a viewing tool like Adobe Acrobat, the viewer will look for (and probably find) the same fonts installed on the local machine instead.

resubset-subset-fonts Allows already subset fonts to be re-subset if possible (see “subset-embedded-fonts” above). Subsetting can significantly reduce the size of the PDF document if a font features thousands of glyphs, such as Mandarin. By re-subsetting a subset font in a PDF document, you are replacing it with a subset that will only contain the glyphs in currently use in the document.

Suppose you have a long PDF document that uses Mandarin characters. You decide to create a summary version of this file by deleting all but the first two pages. After re-subsetting, the Mandarin characters that no longer appear in the document are removed.