In a music theory exam, you might be asked to change an open score (4 staves) into a close score (2 staves), or vice versa. A close score can also be called a “short” score.
Mostly this is just about copying out the notes correctly and neatly, but watch out for the following:
In a vocal or piano close score, the tenor part is written in the bass clef, but in an open score, it normally uses the octave treble clef. (The notes in the octave treble clef sound an octave lower than in normal treble clef). Make sure the tenor notes are in the correct register. These two Ds are the same pitch:
In a close score, the top part on the stave always has its stems pointing upwards, and the lower part has is stems pointing downwards. In an open score, the stem direction depends on the position of the note on the stave – if a note is below the middle line, its stem goes up, and if it is on or above the middle line, its stem goes down.
Notes must line up correctly vertically. Notes that are played or sung at the same time should all line up together in a straight line. Copy the alignment carefully from the original.
Sometimes both parts on one stave might share a note. In this open score, the alto and soprano both have the same G here. In short score, you should write the note only once, but give it two stems – an upward stem on the right for the soprano and a downwards one on the left for the alto.
If two parts share notes of different values, then you will need to write the note twice, one after the other. Write it so that the stems meet in the middle.
When two parts have notes that are an interval of a second apart, put the lower part to the right of the higher part, and make sure the stems meet in between the notes. Any accidentals should go on the left, and not between any notes played at the same time.
In an open score, rests are written in the normal way. In a short score, a rest might only apply to one of the parts on the stave. To make it clear which part it belongs to, write the rest higher or lower down on the stave, out of the way of the part it doesn’t belong to. (If both parts share the same rest, you can write a single one in the normal position).