# pdflatex: Handling of fonts when including other pdfs

I was curious about one fact: How will pdflatex deal with fonts embedded in pdfs it includes?

For example: When I include 100 pdf-files (e.g. using \includegraphics) will the generated output file contain the embedded fonts a hundred times (one complete set for each file included)?

Or is it smart enough to recognize that it already has the requested fonts and allow therefore file size reduction?

It is smart enough but sometimes this can lead to problem. See e.g. Ligatures in figures and pdftex and other answers about \pdfinclusioncopyfonts