+@lilypond[verbatim,quote,fragment]
+ \clef treble
+ c'1
+ \clef treble
+ c'1
+ \set Staff.forceClef = ##t
+ c'1
+ \clef treble
+ c'1
+@end lilypond
+
+@noindent
+To be more precise, it is not the @code{\clef} command itself that
+prints a clef. Instead, it sets or changes a property of the
+@code{Clef_engraver}, which then decides by its own whether to
+display a clef or not in the current staff. The @code{forceClef}
+property overrides this decision locally to re-print a clef once.
+
+When there is a manual clef change, the glyph of the changed clef
+will be smaller than normal. This behaviour can be overridden.
+
+@lilypond[verbatim,quote,fragment]
+ \clef "treble"
+ c'1
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+ \override Staff.Clef.full-size-change = ##t
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+ \revert Staff.Clef.full-size-change
+ \clef "bass"
+ c'1
+ \clef "treble"
+ c'1
+@end lilypond
+
+@snippets