+This also could be implemented as a music function, in order to
+restrict the modifications to a single music block. Notice how
+@code{ly:context-pushpop-property} is used both as a
+@code{\temporary@tie{}\override} and as a @code{\revert}:
+
+@lilypond[quote,verbatim]
+desaturate =
+#(define-music-function
+ (parser location music) (ly:music?)
+ #{
+ \applyContext
+ #(lambda (context)
+ (define (desaturate-grob grob)
+ (let* ((grob-def (ly:context-grob-definition context grob))
+ (color (ly:assoc-get 'color grob-def black))
+ (new-color (map (lambda (x) (min 1 (/ (1+ x) 2))) color)))
+ (ly:context-pushpop-property context grob 'color new-color)))
+ (for-each desaturate-grob '(NoteHead Stem Beam)))
+ #music
+ \applyContext
+ #(lambda (context)
+ (define (revert-color grob)
+ (ly:context-pushpop-property context grob 'color))
+ (for-each revert-color '(NoteHead Stem Beam)))
+ #})
+
+\relative g' {
+ \override NoteHead.color = #darkblue
+ \override Stem.color = #darkblue
+ \override Beam.color = #darkblue
+ g8 a b c
+ \desaturate { d c b a }
+ g b d b g2
+}
+@end lilypond