The piano pedals are additions to the piano instrument that enhance a performance in various ways. There are three pedals, each with a separate and distinct function. These are attached to a panel reaching from just behind the keyboard on a piano to the floor, and are played with the pianist's foot. Starting from the left, there is the soft (more correctly una corda/una corde), sostenuto, and sustain (or damper; "forte"). The sostenuto pedal is not found on all pianos, and on others it serves an entirely different purpose than the function described below. Most piano pieces, including the vast repertoire of classics, only require use of the sustain pedal, but the una corda pedal is used occasionally. Very rarely the sostenuto is used, its popularity emerging with new composers utilizing its unique function. Although beginning piano players will not encounter much indication on when or where to use these pedals, they are essential to creating the sound so ubiquitously associated with the piano.
Playing the pedals
When playing classical repertoire, in most cases distinct instructions will be given. The pedals are played with your foot; the sustain with your right, soft with left. The middle pedal is, again, rarely used, but it replaces the function of the sustain pedal in a limited way, so it would be played with the right foot.
Place your foot flat on the floor when progressing through long passages without any pedal usage. When a pedal is meant to be played, put the heel of your foot on the ground directly in front of the pedal. Pivot downwards, pressing down the pedal with the broad ball of your foot. Your heel should not leave the ground while depressing a pedal.
The sustain pedal is the most often used pedal. A cursory observer of any pianist playing any song (composed after the invention of this pedal) will notice this is depressed quite often. It releases the strings of the dampers, felt-covered pieces of wood that deaden a string's vibration. This causes any sound produced by the hammers of a piano to continue vibrating even after the key activating that hammer is released. Used incorrectly, the pedal can cause notes to become confused and sound inarticulate. However, this pedal's function is necessary to execute most passages. The action of depressing and releasing the pedal should be clear and distinct. The pedal should either be depressed completely, or released all the way. Holding the sustain pedal halfway down creates a 'growling' sound as the vibrating strings are partially muffled by the felt. This convention is found in some compositions of Ravel's, but is not a common execution or use of the sustain pedal.
The 'new' marker is one indication of when to play the pedal. You would depress the sustain pedal at the moment in the music when the bracket (highlighted in orange) 'begins,' and release it when the bracket is closed. In this example, the sustain pedal should be held throughout the light red section, and released when the music passes the dark red rectangle on the right.
Classical repertoire uses a two-part marker to indicate when to depress the sustain pedal, consisting of an ornamental 'Ped.' to signal depression, and a large asterisk to indicate release. This is displayed on the left in the same context as the 'new' style above, and the pianist would play this particular section exactly the same as before. A drawback to this style was that it was not particularly clear what note the pedal marker was indicating, and thus was difficult to discern exactly when to release or depress.
The soft pedal is common in post-Classical works, such as compositions by Beethoven or Chopin. Its melodramatic tone enhances soft passages, but it is important to know the difference between playing with the dynamic marking piano and with the soft pedal. The soft pedal does not give you license to play harshly when depressing it, simply to sound soft. Piano is a dynamic marking to play quietly but with good tone. The soft pedal smooths out a note's attack, creating a very mellow texture. It is possible to play Forte with the soft pedal, just as possible as it is to play Pianissimo without the soft pedal.
The marker is the words una corda (or una corde). Depress the soft pedal from the beginning of the words until instructed to release, at the words tre corda (or tutte corde). In the examples to the right, the soft pedal would be held from the very beginning of the music until the dark red rectangle after the tre corda.
The middle pedal, called sostenuto, is rarely used, but is indicated in music with clear instructions. This pedal keeps the dampers up that were raised when it was depressed, enabling staccato play independent of the sustained note. It is sometimes used arbitrarily by pianists who cannot hold down a pedal tone. On smaller piano models (uprights, consoles, etc.) the sostenuto is usually replaced by the celeste or practice pedal. This pedal is indicated by a indentation next to the pedal's most depressed state, allowing the pianist to slide it into a continuously depressed position. The celeste is not used in standard performance, and was created for practical reasons. When depressed, all notes are softer than the una corda. Use this pedal (if your piano has it) if quietude is a necessity.