The Accidentals

Those in parentheses are precautionary ones; they serve to remind that a note has returned to its "natural" state after being altered. Obviously, this applies across the barline and not within the same...

The basic rule states that the added alteration applies only to the measure in question and the relative pitch, so in theory, once the measure is finished, parentheses shouldn't even be used (e.g., they are not used in jazz). However, in a harmonic context, where besides the single pitch the momentary tonal framework also matters, it is good practice to indicate them until tonal clarification occurs (usually within 1-2 measures).

They are also used in the case of a chord with the presence of a double alteration on the same note name (e.g., in the diminished seventh B-D-F-Bb that resolves to Ab, the B would be indicated as natural if you want to use parentheses).

There are authors where the concept of a note without alteration does not exist, so every natural note has a natural sign in front... perhaps some contextualization is needed.

Are we talking about classical, dodecaphonic, jazz repertoire, etc., or what?

Nowadays, it is necessary to read the composer's introductory notes (in reality, this is always true), where often everyone defines their own criteria for ease of reading, in the sense that abandoning a tonal logic can lead to many difficulties in reading if it becomes cumbersome, in my opinion like Berg did (for example, a composer who falls into the category described by Marta), where every note is preceded by a natural sign.

As is also the case, having an alteration followed by a natural sign and vice versa without tonal references is a delirium... so I agree as well, what are we even talking about?

As usual, one can never find a clear and unambiguous answer; it is certainly the fault of the question and my fault for being a beast who doesn't understand an "H" at a theoretical level... so my music stops short... my problem.

Dlet's say a context that is "normal" to me is when I have a key signature and I can say that a song, a piece, is an E-... for example

Giove wrote:

As usual, one can never find a clear and unique answer; it is certainly the fault of the question and my fault for being a beast who doesn't understand an "H" at a theoretical level... so music stops at a certain point... my problem.

Diciamo un contesto che per me è "normale" è quando in chiave ho un armatura e riesco a dire che una canzone, un brano è un mi-...ad esempio

Look, based on the examples I have found—examples of compositions by Mozart, Schumann, etc.—I have tried to simplify everything, and I hope this can be a way (already used, moreover) to allow for as simple and clear a reading as possible of what I write:

very similar to what has already been written above, when I have an altered note, for example, I am in C major and in the same measure two Fs appear, one of which is #; for example, in a piece for piano, in the lower staff there is F#, and in the upper staff the F is natural; in that specific case (within the same measure), [I specify] that the F is natural by placing the natural sign before the note.

In the case, however, of an F# before a specific note in a measure, and in the following measure the same F is natural, I specify it only if it is in the same position (vertical) as the previous F; I consider the other Fs to be natural, just as when you have accidentals in the key signature—for example, if you are in Bb major, you have Bb and Eb; if in one measure you play the E natural, so you place the natural sign before it, for instance placing the Eb on the 2nd empty space from the top down on the staff of the bass clef (of the bass), when the note reappears:

- in the same measure (and it is flat) you can insert the flat symbol in parentheses.

- then (staying always in the same measure), you have this E with the natural sign before it, still on the bass staff; perhaps here it is better that (being in the same measure) I put in parentheses (if there are any) the other Es that remain unchanged, i.e., with the flat.

- in the following measure, in theory, it should be the same, always the symbol b in parentheses, but for the other Es (at other pitches) it is not necessary because you already have the flat in the key signature, provided that you do not want to use it without the flat, i.e., natural.

The problem is, when this E is naturalized (with the natural sign) and the same note, therefore in the same vertical position, reappears after 5/6 measures, should it be specified or not?

Or is it taken for granted that (also based on the harmonic progressions of the piece, if it is clear that one is always in that key, or in its relative minor (G minor), or another of the nearby major keys, Eb major (Bb-Eb-Ab all flats, and relative minor C minor, with B natural, if altered)) at that point the E has returned to being flat without specifying its state through the use of the symbol in parentheses?

To define everything, we are in a tonal context.

Sometimes they are even found in small groups.

A useful book can be: Manuale di scrittura musicale by Lorenzo Ferrero (EDT)

Giove wrote:

Let's say a context that for me is "normal" is when I have a key signature and I can say that a song, a piece, is in E-... for example

Perfect: let's follow this example and try to be practical. If you are in E minor, it means that in the key signature you have only one alteration, namely F sharp. Let's say your piece modulates and ends up in C major, passing through G. In C major there are no alterations, so obviously the F natural must be indicated (and NOT in parentheses, obviously). Alterations in the conventional notation system apply to the entire measure, so if you indicate the F natural once, it will be sufficient in that measure (on all Fs at that pitch, not on all Fs in the measure, pay attention). Let's assume the piece returns "home" (very likely, moreover): returning to E minor we will have the F sharp again and, in theory, nothing would need to be done, but "just in case", especially if the modulating section has been long enough to consolidate the F natural (I am speaking of the specific case, obviously), it is better to indicate, only once and when an F appears, the alteration, in parentheses, just to...

Finally some practical interventions, thank you. Now the matter is clearer

Frank wrote:

A useful book could be: Manuale di scrittura musicale by Lorenzo Ferrero (EDT)

Darn, an entire book just to tell the story of Carlos's 5 lines ...

Piccinesco wrote:

The problem is, when this is naturalized (with the natural sign) and the same note, therefore in the same vertical position, reappears after 5/6 measures, should it be specified or not?

Or is it taken for granted that (also based on the harmonic progressions of the piece, if it is clear that one is always in that key, or in its relative minor (G minor), or another of the nearby major keys, Eb major (B-E-A all flats, and relative minor C minor, with B natural, if altered)) at that point the E has returned to flat without specifying its state through the use of the symbol in parentheses?

To define everything, we are in a tonal context.

Examples too advanced for me. Can you post something? An image, an attachment?

Giove wrote:

Damn, an entire book just to tell the story of Carlos's 5 lines ...

Probably that book, which I am not familiar with, addresses the issue in a very comprehensive way, going all the way up to the present day and not limiting itself to the use of accidentals. I preferred to start with a practical example to help even you, if you still need it, to ask what you want to know.

Who knows why there is always someone who understands instantly, even if they don't know the book, ... and someone who understands less

It seems to me that the answer can be found in any basic theory book such as Luigi Rossi, who dedicates a small paragraph of 15 lines to the subject ... another thing is the treatment of a text dedicated to musical notation in its entirety, not understood from a compositional point of view but merely of the notation

And everything cannot be extinguished in 15 lines

Ferrero doesn't only talk about accidentals.. down here you can find a bit of preview http://books.google.it/books/about/Manuale_di_scrittura_musicale.html?hl=it&id=iY7Md4_3B-8C

Ok, thanks again