I was trying to describe a scale of musical notes on the piano to a friend and I did not know how to say it correctly. The scale of musical notes start on a black key and then moves on to higher notes in the series. I know that when you raise a note with a semitone you get a sharp and when you lower a note with a semitone you get a flat but I have not yet raised/lower it because its the starting point. So I was wondering how to write/say a black key as a starting point in my scale of notes? Is it dependent on whether its ascending or descending?
You can start a scale on any note, whether it is a white key or a black key. You will then need to ascend with the correct sequence of tones and semitones depending on the type of key that you want e.g. tone, tone, semitone, tone, tone, tone, semitone for a major key (you should now be back on the starting note).
You probably know that the black keys can be called sharp or flat. E.g. the one between F and G could be called F sharp or G flat. You could use either name and build a scale on it but you will find that some choices will be simpler than others. With the wrong choice, you may need to use double sharps or double flats. Even if this is not required, usually one choice will be simpler.
Db will require 5 flats rather than 7 sharps for C#.
Eb will require 3 flats. D# would require double sharps.
F# requires 6 sharps and Gb requires 6 flats so that is a dead heat.
Ab requires 4 flats. G# would require double sharps.
Bb requires 2 flats. A# would require double sharps.
So, for major keys, you could always use the flat names for the starting point of keys.
For minor keys, the answer will be different. C# minor will preferable to Db minor .
It could be either. But to make life a little simpler, with fewer sharps or flats to spell each correctly, the following are the usual key names.
Bb rather than A#. Only has 2b.
Eb rather than D#. Only has 3b.
Ab rather than G#. Only has 4b.
Db gives 5b, C# gives 7#.
F# gives 6#, Gb gives 6b, so it's the same.
If you know which key you can say it's a scale in that musical key. A major scale starting on Bflat is described as a 'Bflat major scale'.
It doesn't really matter which name for the black key you choose to use, in the end, except that the scale might be easier to think about from one perspective than another.
In truth, you have the same problem with white keys. A scale starting on C could be called B#, but it's just not commonly done. It's much easier to think about it as a C scale.
Summary: Use a letter and the word "sharp" or "flat" to name your first note if the first note is played by a black key. The fact that it is the first note you play is irrelevant. But you may want to consider what other notes are in your sequence in order to decide which name to use (the "sharp" name or the "flat" name) for the first note.
In modern Western music, in each octave there are seven notes with the names C, D, E, F, G, A, and B. These are the natural notes, and they are played by the white keys on a piano.
Notes can also be named by adding the words "sharp", "flat", "double-sharp", or "double-flat" to one of the seven letters that name the natural notes.
The name of a note says what the pitch of the note is, and you can use it to find out which key on the piano will play that note. The sharps and flats are relative to the natural notes, not relative to any tune or sequence of notes you want to play. There is absolutely no reason you cannot use "sharp" or "flat" in the name of the first note in your sequence.
Each note generally has more than one possible name. E sharp is another name for F, because F is one half-tone above E. Another name for F is G double-flat, because F is two half-tones below G. The note between D and E has three names: D sharp, E flat, and F double-flat.
To name one of the "black key" notes you will have to use one of the terms "sharp", "flat", "double-sharp", or "double-flat". All of the names of those notes include those terms. So that's that.
As other answers have pointed out, however, often one name will be better than another, depending on what other notes you intend to play. When we play a sequence of notes close together and going up, we prefer their names to include an "ascending" sequence of letters. If you want to play three notes starting with the note between D and E, then the note played by the F key, then the note played by the G key, you could name them "E flat, F, G." Or you could decide to name them "D sharp, E sharp, F double-sharp," which is technically correct (and sometimes does occur in published piano music), but I don't have any reason to think you would want to do that. (When I see a "double-sharp" note name, it seems there's always a reason beyond just the desire to play a simple sequence like this.) Technically, you could even say "F double flat, G double flat, A double flat," but I don't think I have ever seen music written that way.
If you start with the note between D and E, then play the note named E, and then the note between F and G, "D sharp, E, F sharp" would be a good way to name them. You could also say "E flat, F flat, G flat," though the first way is usually how I'd say it. But if you name the first note F double-flat, you put yourself in a bad spot, because the next note is either F flat (same letter) or E (going "down" in the alphabet while the music is going "up").