-Internally, this sets the @code{fontSize} property. This in turn
-causes the @code{font-size} property to be set in all layout
-objects. The value of @code{font-size} is a number indicating the
-size relative to the standard size for the current staff height.
-Each step up is an increase of approximately 12% of the font size.
-Six steps is exactly a factor of two. The Scheme function
-@code{magstep} converts a @code{font-size} number to a scaling
-factor. The @code{font-size} property can also be set directly,
-so that only certain layout objects are affected.
-
-@lilypond[verbatim,quote,relative=2]
-\set fontSize = #3
-c4.-> d8---3
-\override NoteHead #'font-size = #-4
-c4.-> d8---3
-\override Script #'font-size = #2
-c4.-> d8---3
-\override Stem #'font-size = #-5
-c4.-> d8---3
+The @code{fontSize} value is a number indicating the size relative
+to the standard size for the current staff height. The default
+@code{fontSize} is 0; adding 6 to any @code{fontSize} value
+doubles the printed size of the glyphs, and subtracting 6 halves
+the size. Each step increases the size by approximately 12%.
+
+The scheme function @code{magnification->font-size} is provided
+for convenience since the logarithmic units of the
+@code{font-size} property are not entirely intuitive. For
+example, to adjust the musical notation to 75% of the default
+size, use:
+
+@example
+\set fontSize = #(magnification->font-size 0.75)
+@end example
+
+The scheme function @code{magstep} does the opposite: it converts
+a @code{font-size} value into a magnification factor.
+
+The @code{fontSize} property will only affect notational elements
+that are drawn with glyphs, such as noteheads, accidentals,
+scripts, etc. It will not affect the size of the staff itself,
+nor will it scale stems, beams, or horizontal spacing. To scale
+stems, beams, and horizontal spacing along with the notation size
+(without changing the staff size), use the @code{\magnifyMusic}
+command discussed above. To scale everything, including the staff
+size, see @ref{Setting the staff size}.
+
+Whenever the @code{fontSize} @i{context property} is set, its
+value is added to the value of the @code{font-size} @i{grob
+property} for individual layout objects, before any glyphs are
+printed. This can cause confusion when setting individual
+@code{font-size} properties while @code{fontSize} is already set:
+
+@lilypond[verbatim,quote,fragment]
+% the default font-size for NoteHead is 0
+% the default font-size for Fingering is -5
+c''4-3
+
+\set fontSize = -3
+% the effective font size for NoteHead is now -3
+% the effective font size for Fingering is now -8
+c''4-3
+
+\override Fingering.font-size = 0
+% the effective font size for Fingering is now -3
+c''4-3