Notation

This section will provide a clear overview of how to notate harmonics. Since harmonics on string instruments usually pitch differently than plucked or bowed notes played on the same point on the string one can easily get confused when reading notated harmonics.

I translated a section from the book Noter by Börje Tyboni (1996).

(My translation)

Natural harmonics are written as the sounding pitch with a small circle above the note head. The harmonic can also be written as a hollow rhombus which tells urs the point where the string is touched. In both cases the strings number or name should be written out. (Tyboni. 1996. p. 239)

The following example shows the natural harmonics notated on the G-string of the upright bass.

Tyboni continues:

Artificial harmonics are played by pressing down on the string with one finger and gently touching the string at another point with another finger (...) The harmonic then typically pitches two octaves above how the pitch would be if only the first action would be applied.

Artificial harmonics are written with two note heads on a common shaft. The lower is a regular filled or hollow note head which tells us the point the string should be pressed, the upper is a hollow rhombus specifying the point of the "touching finger".
Sometimes a thid note head is written to show the true pitch, which is unnecessary as notation with two note heads are completely unambigous. (Noter, Tyboni. p 240)

The note example below shows an example notated with the two note heads as described above.

It should be noted that the pitch gets higher the closer the interval. As seen above, The interval of a fifth gives a lower pitch than the interval of a third, as seen with example three above, pitch pitches G6.