The improvisational prelude in the 19th century could be regarded as a soundcheck in which the instrument and the acoustics are tested. While performing, it’s important to include the whole tonal range of the keyboard, from low to high pitches. This can’t be done using only harmonic progressions. During the evolution of the piano as an instrument the pedal becomes an important tool and the tonal range is increased from five to seven octaves, which allows many possibilities for exploring the keyboard. In the 19th-century tradition we mainly distinguish three techniques for exploring the keyboard:
scales and scale figures
By using and combining these three techniques, a chord progression can be spread out over the whole keyboard. This is the biggest step in entering the domain of preluding.
Moscheles' prelude nr.1 opus 73 contains these three main techniques:
Hummel's prelude in B major Op. 67:
arpeggio techniques / harmonizations
Piano methods throughout the 19th century offer countless examples of explorations in the form of exercises. These exercises formed the backbone of a pianistic training. The usual contents are scales, arpeggios, interval explorations and embellishments. It could be seen as a far echo of the use of 'diminutions', a Renaissance technique in which longer note values are replaced by a series of shorter ones. Among the most interesting publications of such exercises are those of Dussek, Adam, Montgeroult, Müller, Cramer, Hummel, Herz, Czerny, Moscheles, Zimmermann, Kullak and Liszt.
Although written for harpsichord or harp, the "Twelve flourishing movements arising from the diatonic scale and the common chord" provided by August Friedrich Christoph Kollmann (1756-1829) in the third lesson of An Introduction to the Art of Preluding (1792) offers many possibilities for exploring the keyboard.
More elaborated in a pianistic way are the examples of Philip Anthony Corri (1784-1832) in Original System of Preluding (1812), in which all main exploration techniques -- scale figures, arpeggios and embellishments -- are used in a balanced way.
EXERCISES FOR STUDYING
Since studying all the existing exercises may take more than a lifetime, it is a better choice to acquire the 'exploration' skills through a selection of specific exercises. Selecting the exercises is not easy as the different options can also be strongly influenced by personal taste. But some skills are so important that they are indispensable for moving freely in exploring within a tonal field.
A selection of these exercises, with explanation, is provided by clicking on the links below.