Reading in a key

The sharps or flats printed right after the clef are the key signature. They are not notes. They are a standing instruction: every note on that letter is sharpened, or flattened, for the whole piece.

So with a sharp on the F line, a plain note on the F line means F sharp. Nothing is written in front of it, and it is still sharp. That is what makes a signature worth having: it is written once instead of on every note.

It applies to the letter, not the position. If the signature sharpens F, then every F is sharp, high or low, either clef.

You do not need to know which key it is to read it. Look at which lines the signs sit on, and apply them.

a sign in the signature = every note of that letter, always

Two sharps at the front. Both of these plain notes are sharp: F sharp and C sharp.

Practise this in the trainer — it opens with this lesson the first time the concept comes up.